A 33-year-old otherwise healthy man presented with a recurrent nodule above and slightly to the left side of the gluteal cleft (“butt crack”) (Figure 1). This lesion would occasionally drain serosanguineous fluid. The patient complained that it waxed and waned but never healed for the past 2 years. He denied any associated fevers, chills, night sweats, malaise or weight loss. On physical examination, there was an approximately 3x3 cm reddish brown nodule with central ulceration and drainage, above and slightly to the left side of the gluteal cleft. An excisional biopsy was performed.
WHAT IS YOUR DIAGNOSIS?
To learn the answer, go to page 2
{{pagebreak}}
Diagnosis: Pilonidal Sinus
Pilonidal sinus disease (PSD) describes an often painful cutaneous lesion that typically occurs in the natal cleft of the sacrococcygeal area (Figure 1). A pilonidal sinus is sometimes referred to as pilonidal cyst, and when localized to the interdigital area it is referred to as barber’s interdigital pilonidal sinus. Herbert Mayo first described a pilonidal sinus in 1833 as a hair-containing sinus,1 but the term “pilonidal” was coined in 1880 by R.M. Hodges to suggest a nest of hair (Latin: pilus = hair and nidus = nest). During World War II, this condition commonly occurred in jeep drivers due to repeated chafing, leading to the nickname “jeep seat disease.”
PSD occurs in about 0.7% of the population, with an incidence of 25 in 100,000. Peak age of presentation ranges from 15 to 30, with the mean age being 20.2 This condition affects males twice as much as females, with 80% of the afflicted patients being male.3 This condition is also more common in Caucasians than African Americans or Asians due to differences in characteristics and growth patterns of hair.4 Men are at a higher risk due to their more hirsute nature.5 Other risk factors for PSD include thick skin, obesity, deep gluteal cleft, sedentary occupation and local irritation or trauma.6,7
Etiology and Pathogenesis
Understanding of this condition has been filled with controversies, particularly related to the etiology. PSD was initially thought to be a congenital condition and classified as a dermoid cyst. This theory suggests that the lesion developed from an infection of an epithelialized tract along the natal cleft, which occurs from the absence of primitive ectoderm fusion.7
In contrast, the acquired theory is more widely accepted as the pathogenesis of PSD. Several hypotheses have been proposed to explain the etiology, all accounting for the particular characteristics associated with the anatomic region, such as the pressure effects and shearing force.
The current view of PSD starts with a keratin plug in the natal cleft hair follicle resulting in an infection, which increases its risk of becoming distended and obstructed. These dilated follicles rupture in the subcutaneous tissues, producing an acute or chronic inflammation along with the development of an abscess or a tract (Figure 2). The hair follicle and cellular debris that accumulate in the skin could further enhance the inflammatory reaction by acting as a foreign body.8,9 The material accrued can become infected with bacteria, which has 2 important impacts. First, toxins from the bacteria can break down proteins and liquefy tissues. Second, as part of the inflammatory process, the body floods the area with neutrophils and macrophages. The inflammatory reaction to the damaged follicle and surrounding tissue can become a chronic condition over time. PSD is prone to recurrent infections due to the presence of moisture, bacteria, hair and friction.10 Although malignant transformation is rare, cases of squamous cell carcinoma and verrucous carcinoma have been reported.11
In addition, PSD is part of group of diseases called follicular occlusion syndrome, which includes hidradenitis suppurativa (acne inversa), acne conglobata (severe nodulocystic acne) and dissecting cellulitis (perifolliculitis capitis abscedens et suffodiens). Commonly coexistent, these conditions are defined by a similar process in which hair follicles become blocked with keratin and then rupture, resulting in an inflammatory skin condition. PSD is often found in patients with hidradenitis suppurativa. Because both types of lesions can occur in the natal cleft, it is important to distinguish the 2 as the treatments are different.12
Clinical Features
Patients with PSD may present with small abscesses or pits on or off the midline, at the level of the coccyx, about 4 cm to 10 cm from the anus. These patients are typically heavy hirsute males and perspire profusely. A malodorous discharge or occasional bleeding from the lesion may be present. Also, a history of prior treatment of PSD is common due to its recurrent nature. The main complaint is pain, but fever may be present in rare cases. One or several pits that communicate with a deeper cavity by an epithelialized tract generally accompany an infected pilonidal sinus.7
A patient with PSD can present in 1 of the following stages:
1. Asymptomatic – This is usually discovered during routine examination.
2. Acute inflammation, infection and abscess formation – Patient presents with pain as a result of swelling and possibly purulent discharge. Examination can reveal cellulitis over the natal cleft, with the patient intolerant to touch to the afflicted region.
3. Chronic disease – Patient presents with chronic pain, recurrent infection over a 2-year period, and possibly multiple affected sites. Signs of inflammation and swelling can also be observed.
4. Complex or recurrent disease – This stage is usually related to re-infection of neighboring hair follicles or from postoperative wound infection.7,10
Histopathology
Histologic examination of a pilonidal sinus shows a sinus tract lined by granulation tissue and in some areas, stratified squamous epithelium (Figure 3). The sinus is infiltrated by neutrophils, lymphocytes, plasma cells and sometimes hemosiderin-laden macrophages. The tract leads to a bulbous expansion in the lower dermis and subcutaneous tissue where a chronic abscess cavity lies, which contains a hair follicle in 50% to 75% of cases. Foreign body granulomas in the vicinity of the hair may be present.12,13
Differential Diagnosis
In some cases, a pilonidal sinus can be confused with other inflammatory lesions with similar histological features such as granulation tissue and foreign-body giant cells. Distinguishing factors between these conditions often relies on clinical expertise.
- Hidradenitis suppurativa is a relapsing disorder of the folliculopilosebaceous units characterized by abscesses, epidermoid cysts and sebaceous cysts that occur on the buttocks. These cysts can sometimes contain hair shafts.
- Anal fistula is a perianal extension from an internal opening within the anal canal and can present with anal mucus discharge.
- Pyoderma gangrenosum consists of a rare, chronic neutrophilic dermatosis that may contain hair shafts.
- Perirectal abscess results from an infection that occurs as a painful erythematous lump near the anus. It usually presents with pus and can resolve on its own.
- Furunculosis is a deep infection of hair follicles that differs from a pilonidal sinus due to its pathogenesis.
- Anal fissure presents as a small oval-shaped tear in skin along the natal cleft. This lesion typically causes severe pain and bleeding with bowel movements.
Other granulomatous conditions occurring in the gluteal cleft such as Crohn’s disease, mycetoma, perianal tuberculosis and syphilitic granuloma can present similarly to PSD.12,13
Treatment
Due to the wide spectrum of PSD presentations, treatment course depends on the clinical features and ranges from simple excision and drainage to extensive flap procedure. The American Society of Colon and Rectal Surgeons (ASCRS) made several recommendations in 2013 regarding the treatment for various presentations of PSD (Tables 1 and 2).
Asymptomatic lesions typically do not require treatment. In the absence of an abscess, gluteal cleft shaving may be employed for both acute and chronic PSD as a primary or adjunct therapy. Because most studies on gluteal cleft shaving have used an arbitrary manner and method, effective frequency and extent of shaving have not been systematically studied. Due to unclear efficacy of topical or systemic antibiotics, ASCRS recommends these agents as adjunct treatment for patients with significant cellulitis, immunosuppression or concomitant systemic illness.14
Acute primary or recurrent PSD accompanied by abscess should be treated with incision and drainage. In patients undergoing incision and drainage, those who received curettage showed greater rates of complete healing and lower incidences of recurrence than those who did not receive curettage. Based on the surgeon and patient preference, recommended surgical options for the treatment of PSD included excision and primary repair, excision with healing by secondary intention and excision with marsupialization. In cases of complex and multirecurrent chronic PSD where other methods have failed, flap-based procedures including rhomboid flap, Karydakis flap, cleft-lift technique and V-Y advancement may be performed.14
Our Patient
Biopsy results showed a sinus tract lined by stratified squamous epithelium and granulation tissue. Inflammatory cells including neutrophils, lymphocytes and plasma cells infiltrated the sinus, and a few hemosiderin-laden macrophages were also present. The sinus led to an abscess cavity in the lower dermis, which contained a hair follicle and foreign-body granulomas.
Due to the length and recurrent nature of the PSD, our patient was referred to a general surgeon for an excision and repair procedure. Involved skin and subcutaneous tissue were excised using electrocautery after administration of local anesthetics. A funnel-shaped excision was made deep to the incision in order to completely remove the track only. The wound was washed, cleaned and closed with gauze. The patient was followed at the surgery clinic for postoperative care and then with us regularly.
Conclusion
Pilonidal sinus is a painful lesion that typically occurs in the natal cleft. This lesion results from a keratin plug in a hair follicle becoming infected, rupturing the subcutaneous tissue, becoming acutely or chronically inflamed, or developing into an abscess or a tract. Due to its pathogenesis, this lesion has a wide spectrum of presentations ranging from asymptomatic lesions to a complex and recurrent abscess. Various treatments are available for PSD depending on the presentation.
Ms. Chen is a student at Downstate SUNY College of Medicine in Brooklyn, NY.
Dr. Liu is with department of dermatology at State University of New York Downstate in Brooklyn, NY.
Mr. Malik is a student at State University of New York Downstate College of Medicine in Brooklyn, NY.
Mr. Patel is a student at Albert Einstein College of Medicine in Bronx, NY.
Dr. Khachemoune, section editor of Derm DX, is with department of dermatology at State University of New York Downstate in Brooklyn, NY, and Veterans Affairs Medical Center Dermatology Service in New York, NY.
Disclosure: The authors report no relevant financial relationships.
References
1. da Silva JH. Pilonidal cyst: cause and treatment. Dis Colon Rectum. 2000;43(8):1146-1156.
2. Notaro JR. Management of recurrent pilonidal disease. Semin Colon Rectal Surg. 2003;14(4):173-185.
3. Al-Khamis A, McCallum I, King PM, Bruce J. Healing by primary versus secondary intention after surgical treatment for pilonidal sinus. Cochrane Database Syst Rev. 2010;(1):CD006213.
4. Berry DP. Pilonidal sinus disease. J Wound Care. 1992;1(3):29-32.
5. Varnalidis I, Ioannidis O, Paraskevas G, et al. Pilonidal sinus: a comparative study of treatment methods.
J Med Life. 2014;7(1):27-30.
6. Søndenaa K, Andersen E, Nesvik I, Søreide JA. Patient characteristics and symptoms in chronic pilonidal sinus disease. Int J Colorectal Dis. 1995;10(1):39-42.
7. De parades V, Bouchard D, Janier M, Berger A. Pilonidal sinus disease. J Visc Surg. 2013;150(4):237-247.
8. Bradley L. Pilonidal sinus disease: a misunderstood problem. Wounds UK. 2006;2:45-53.
9. Von laffert M, Stadie V, Ulrich J, Marsch WC, Wohlrab J. Morphology of pilonidal sinus disease: some evidence of its being a unilocalized type of hidradenitis suppurativa. Dermatology. 2011;223(4):349-355.
10. Timmons J. Diagnosis, treatment and nursing management of patients with pilonidal sinus disease. Nurs Stand. 2007;21(52):48-56.
11. Nunes LF, Castro Neto AK, Vasconcelos RA,
et al. Carcinomatous degeneration of pilonidal cyst with sacrum destruction and invasion of the rectum. An Bras Dermatol. 2013;88(6 suppl 1):59-62.
12. Weedon D. Weedon’s Skin Pathology. London, United Kingdom: Churchill Livingstone; 2009.
13. Chintapatla S, Safarani N, Kumar S, Haboubi N. Sacrococcygeal pilonidal sinus: historical review, pathological insight and surgical options. Tech Coloproctol. 2003;7(1):3-8.
14. Steele SR, Perry WB, Mills S, Buie WD. Practice parameters for the management of pilonidal disease. Dis Colon Rectum. 2013;56(9):1021-1027.
15. Armstrong JH, Barcia PJ. Pilonidal sinus disease. The conservative approach. Arch Surg. 1994;129(9):914-917.
16. Lund JN, Leveson SH. Fibrin glue in the treatment of pilonidal sinus: results of a pilot study. Dis Colon Rectum. 2005;48(5):1094-1096.
17. Seleem MI, Al-hashemy AM. Management of pilonidal sinus using fibrin glue: a new concept and preliminary experience. Colorectal Dis. 2005;7(4):319-322.
18. Chaudhuri A, Bekdash BA, Taylor AL. Single-dose metronidazole vs 5-day multi-drug antibiotic regimen in excision of pilonidal sinuses with primary closure: a prospective, randomized, double-blinded pilot study. Int J Colorectal Dis. 2006;21(7):688-692.
19. Kronborg O, Christensen K, Zimmermann-Nielsen C. Chronic pilonidal disease: a randomized trial with a complete 3-year follow-up. Br J Surg. 1985;72(4):303-304.
20. Vogel P, Lenz J. [Treatment of pilonidal sinus with excision and primary suture using a local, resorbable antibiotic carrier. Results of a prospective randomized study]. Chirurg. 1992;63(9):748-753.
21. Rao MM, Zawislak W, Kennedy R, Gilliland R. A prospective randomised study comparing two treatment modalities for chronic pilonidal sinus with a 5-year follow-up. Int J Colorectal Dis. 2010;25(3):395-400.
22. Anderson RE, Lukas G, Skullman S, Hugander A. Local administration of antibiotics by gentamicin-collagen sponge does not improve wound healing or reduce recurrence rate after pilonidal excision with primary suture: a prospective randomized controlled trial. World J Surg. 2010;34(12):3042-3048.
23. Gencosmanoglu R, Inceoglu R. Modified lay-open (incision, curettage, partial lateral wall excision and marsupialization) versus total excision with primary closure in the treatment of chronic sacrococcygeal pilonidal sinus: a prospective, randomized clinical trial with a complete two-year follow-up. Itn J Colorectal Dis. 2005;20(5):415-422.
24. Akca T, Colak T, Ustunsoy B, Kanik A, Aydin S. Randomized clinical trial comparing primary closure with the Limberg flap in the treatment of primary sacrococcygeal pilonidal disease. Br J Surg. 2005;92(9):1081-1084.
25. Topgül K, Ozdemir E, Kiliç K, Gökbayir H, Ferahkös¸e Z. Long-term results of limberg flap procedure for treatment of pilonidal sinus: a report of 200 cases. Dis Colon Rectum. 2003;46(11):1545-1548.
26. Muzi MG, Milito G, Cadeddu F, et al. Randomized comparison of Limberg flap versus modified primary closure for the treatment of pilonidal disease. Am J Surg. 2010;200(1):9-14.
27. Unalp HR, Derici H, Kamer E, Nazli O, Onal MA. Lower recurrence rate for Limberg vs. V-Y flap for pilonidal sinus. Dis Colon Rectum. 2007;50(9):1436-1444.
28. Testini M, Piccinni G, Miniello S, et al. Treatment of chronic pilonidal sinus with local anaesthesia: a randomized trial of closed compared with open technique. Colorectal Dis. 2001;3(6):427-430.
29. Petersen S, Aumann G, Kramer A, Doll D, Sailer M, Hellmich G. Short-term results of Karydakis flap for pilonidal sinus disease. Tech Coloproctol. 2007;11(3):235-240.
30. Ersoy E, Devay AO, Aktimur R, Doganay B, Ozdog˘an M, Gündog˘du RH. Comparison of the short-term results after Limberg and Karydakis procedures for pilonidal disease: randomized prospective analysis of 100 patients. Colorectal Dis. 2009;11(7):705-710.
31. Bessa SS. Comparison of short-term results between the modified Karydakis flap and the modified Limberg flap in the management of pilonidal sinus disease: a randomized controlled study. Dis Colon Rectum. 2013;56(4):491-498.
32. Bascom J, Bascom T. Failed pilonidal surgery: new paradigm and new operation leading to cures. Arch Surg. 2002;137(10):1146-1150.
33. Gendy AS, Glick RD, Hong AR, et al. A comparison of the cleft lift procedure vs wide excision and packing for the treatment of pilonidal disease in adolescents. J Pediatr Surg. 2011;46(6):1256-1259.
A 33-year-old otherwise healthy man presented with a recurrent nodule above and slightly to the left side of the gluteal cleft (“butt crack”) (Figure 1). This lesion would occasionally drain serosanguineous fluid. The patient complained that it waxed and waned but never healed for the past 2 years. He denied any associated fevers, chills, night sweats, malaise or weight loss. On physical examination, there was an approximately 3x3 cm reddish brown nodule with central ulceration and drainage, above and slightly to the left side of the gluteal cleft. An excisional biopsy was performed.
WHAT IS YOUR DIAGNOSIS?
To learn the answer, go to page 2
{{pagebreak}}
Diagnosis: Pilonidal Sinus
Pilonidal sinus disease (PSD) describes an often painful cutaneous lesion that typically occurs in the natal cleft of the sacrococcygeal area (Figure 1). A pilonidal sinus is sometimes referred to as pilonidal cyst, and when localized to the interdigital area it is referred to as barber’s interdigital pilonidal sinus. Herbert Mayo first described a pilonidal sinus in 1833 as a hair-containing sinus,1 but the term “pilonidal” was coined in 1880 by R.M. Hodges to suggest a nest of hair (Latin: pilus = hair and nidus = nest). During World War II, this condition commonly occurred in jeep drivers due to repeated chafing, leading to the nickname “jeep seat disease.”
PSD occurs in about 0.7% of the population, with an incidence of 25 in 100,000. Peak age of presentation ranges from 15 to 30, with the mean age being 20.2 This condition affects males twice as much as females, with 80% of the afflicted patients being male.3 This condition is also more common in Caucasians than African Americans or Asians due to differences in characteristics and growth patterns of hair.4 Men are at a higher risk due to their more hirsute nature.5 Other risk factors for PSD include thick skin, obesity, deep gluteal cleft, sedentary occupation and local irritation or trauma.6,7
Etiology and Pathogenesis
Understanding of this condition has been filled with controversies, particularly related to the etiology. PSD was initially thought to be a congenital condition and classified as a dermoid cyst. This theory suggests that the lesion developed from an infection of an epithelialized tract along the natal cleft, which occurs from the absence of primitive ectoderm fusion.7
In contrast, the acquired theory is more widely accepted as the pathogenesis of PSD. Several hypotheses have been proposed to explain the etiology, all accounting for the particular characteristics associated with the anatomic region, such as the pressure effects and shearing force.
The current view of PSD starts with a keratin plug in the natal cleft hair follicle resulting in an infection, which increases its risk of becoming distended and obstructed. These dilated follicles rupture in the subcutaneous tissues, producing an acute or chronic inflammation along with the development of an abscess or a tract (Figure 2). The hair follicle and cellular debris that accumulate in the skin could further enhance the inflammatory reaction by acting as a foreign body.8,9 The material accrued can become infected with bacteria, which has 2 important impacts. First, toxins from the bacteria can break down proteins and liquefy tissues. Second, as part of the inflammatory process, the body floods the area with neutrophils and macrophages. The inflammatory reaction to the damaged follicle and surrounding tissue can become a chronic condition over time. PSD is prone to recurrent infections due to the presence of moisture, bacteria, hair and friction.10 Although malignant transformation is rare, cases of squamous cell carcinoma and verrucous carcinoma have been reported.11
In addition, PSD is part of group of diseases called follicular occlusion syndrome, which includes hidradenitis suppurativa (acne inversa), acne conglobata (severe nodulocystic acne) and dissecting cellulitis (perifolliculitis capitis abscedens et suffodiens). Commonly coexistent, these conditions are defined by a similar process in which hair follicles become blocked with keratin and then rupture, resulting in an inflammatory skin condition. PSD is often found in patients with hidradenitis suppurativa. Because both types of lesions can occur in the natal cleft, it is important to distinguish the 2 as the treatments are different.12
Clinical Features
Patients with PSD may present with small abscesses or pits on or off the midline, at the level of the coccyx, about 4 cm to 10 cm from the anus. These patients are typically heavy hirsute males and perspire profusely. A malodorous discharge or occasional bleeding from the lesion may be present. Also, a history of prior treatment of PSD is common due to its recurrent nature. The main complaint is pain, but fever may be present in rare cases. One or several pits that communicate with a deeper cavity by an epithelialized tract generally accompany an infected pilonidal sinus.7
A patient with PSD can present in 1 of the following stages:
1. Asymptomatic – This is usually discovered during routine examination.
2. Acute inflammation, infection and abscess formation – Patient presents with pain as a result of swelling and possibly purulent discharge. Examination can reveal cellulitis over the natal cleft, with the patient intolerant to touch to the afflicted region.
3. Chronic disease – Patient presents with chronic pain, recurrent infection over a 2-year period, and possibly multiple affected sites. Signs of inflammation and swelling can also be observed.
4. Complex or recurrent disease – This stage is usually related to re-infection of neighboring hair follicles or from postoperative wound infection.7,10
Histopathology
Histologic examination of a pilonidal sinus shows a sinus tract lined by granulation tissue and in some areas, stratified squamous epithelium (Figure 3). The sinus is infiltrated by neutrophils, lymphocytes, plasma cells and sometimes hemosiderin-laden macrophages. The tract leads to a bulbous expansion in the lower dermis and subcutaneous tissue where a chronic abscess cavity lies, which contains a hair follicle in 50% to 75% of cases. Foreign body granulomas in the vicinity of the hair may be present.12,13
Differential Diagnosis
In some cases, a pilonidal sinus can be confused with other inflammatory lesions with similar histological features such as granulation tissue and foreign-body giant cells. Distinguishing factors between these conditions often relies on clinical expertise.
- Hidradenitis suppurativa is a relapsing disorder of the folliculopilosebaceous units characterized by abscesses, epidermoid cysts and sebaceous cysts that occur on the buttocks. These cysts can sometimes contain hair shafts.
- Anal fistula is a perianal extension from an internal opening within the anal canal and can present with anal mucus discharge.
- Pyoderma gangrenosum consists of a rare, chronic neutrophilic dermatosis that may contain hair shafts.
- Perirectal abscess results from an infection that occurs as a painful erythematous lump near the anus. It usually presents with pus and can resolve on its own.
- Furunculosis is a deep infection of hair follicles that differs from a pilonidal sinus due to its pathogenesis.
- Anal fissure presents as a small oval-shaped tear in skin along the natal cleft. This lesion typically causes severe pain and bleeding with bowel movements.
Other granulomatous conditions occurring in the gluteal cleft such as Crohn’s disease, mycetoma, perianal tuberculosis and syphilitic granuloma can present similarly to PSD.12,13
Treatment
Due to the wide spectrum of PSD presentations, treatment course depends on the clinical features and ranges from simple excision and drainage to extensive flap procedure. The American Society of Colon and Rectal Surgeons (ASCRS) made several recommendations in 2013 regarding the treatment for various presentations of PSD (Tables 1 and 2).
Asymptomatic lesions typically do not require treatment. In the absence of an abscess, gluteal cleft shaving may be employed for both acute and chronic PSD as a primary or adjunct therapy. Because most studies on gluteal cleft shaving have used an arbitrary manner and method, effective frequency and extent of shaving have not been systematically studied. Due to unclear efficacy of topical or systemic antibiotics, ASCRS recommends these agents as adjunct treatment for patients with significant cellulitis, immunosuppression or concomitant systemic illness.14
Acute primary or recurrent PSD accompanied by abscess should be treated with incision and drainage. In patients undergoing incision and drainage, those who received curettage showed greater rates of complete healing and lower incidences of recurrence than those who did not receive curettage. Based on the surgeon and patient preference, recommended surgical options for the treatment of PSD included excision and primary repair, excision with healing by secondary intention and excision with marsupialization. In cases of complex and multirecurrent chronic PSD where other methods have failed, flap-based procedures including rhomboid flap, Karydakis flap, cleft-lift technique and V-Y advancement may be performed.14
Our Patient
Biopsy results showed a sinus tract lined by stratified squamous epithelium and granulation tissue. Inflammatory cells including neutrophils, lymphocytes and plasma cells infiltrated the sinus, and a few hemosiderin-laden macrophages were also present. The sinus led to an abscess cavity in the lower dermis, which contained a hair follicle and foreign-body granulomas.
Due to the length and recurrent nature of the PSD, our patient was referred to a general surgeon for an excision and repair procedure. Involved skin and subcutaneous tissue were excised using electrocautery after administration of local anesthetics. A funnel-shaped excision was made deep to the incision in order to completely remove the track only. The wound was washed, cleaned and closed with gauze. The patient was followed at the surgery clinic for postoperative care and then with us regularly.
Conclusion
Pilonidal sinus is a painful lesion that typically occurs in the natal cleft. This lesion results from a keratin plug in a hair follicle becoming infected, rupturing the subcutaneous tissue, becoming acutely or chronically inflamed, or developing into an abscess or a tract. Due to its pathogenesis, this lesion has a wide spectrum of presentations ranging from asymptomatic lesions to a complex and recurrent abscess. Various treatments are available for PSD depending on the presentation.
Ms. Chen is a student at Downstate SUNY College of Medicine in Brooklyn, NY.
Dr. Liu is with department of dermatology at State University of New York Downstate in Brooklyn, NY.
Mr. Malik is a student at State University of New York Downstate College of Medicine in Brooklyn, NY.
Mr. Patel is a student at Albert Einstein College of Medicine in Bronx, NY.
Dr. Khachemoune, section editor of Derm DX, is with department of dermatology at State University of New York Downstate in Brooklyn, NY, and Veterans Affairs Medical Center Dermatology Service in New York, NY.
Disclosure: The authors report no relevant financial relationships.
References
1. da Silva JH. Pilonidal cyst: cause and treatment. Dis Colon Rectum. 2000;43(8):1146-1156.
2. Notaro JR. Management of recurrent pilonidal disease. Semin Colon Rectal Surg. 2003;14(4):173-185.
3. Al-Khamis A, McCallum I, King PM, Bruce J. Healing by primary versus secondary intention after surgical treatment for pilonidal sinus. Cochrane Database Syst Rev. 2010;(1):CD006213.
4. Berry DP. Pilonidal sinus disease. J Wound Care. 1992;1(3):29-32.
5. Varnalidis I, Ioannidis O, Paraskevas G, et al. Pilonidal sinus: a comparative study of treatment methods.
J Med Life. 2014;7(1):27-30.
6. Søndenaa K, Andersen E, Nesvik I, Søreide JA. Patient characteristics and symptoms in chronic pilonidal sinus disease. Int J Colorectal Dis. 1995;10(1):39-42.
7. De parades V, Bouchard D, Janier M, Berger A. Pilonidal sinus disease. J Visc Surg. 2013;150(4):237-247.
8. Bradley L. Pilonidal sinus disease: a misunderstood problem. Wounds UK. 2006;2:45-53.
9. Von laffert M, Stadie V, Ulrich J, Marsch WC, Wohlrab J. Morphology of pilonidal sinus disease: some evidence of its being a unilocalized type of hidradenitis suppurativa. Dermatology. 2011;223(4):349-355.
10. Timmons J. Diagnosis, treatment and nursing management of patients with pilonidal sinus disease. Nurs Stand. 2007;21(52):48-56.
11. Nunes LF, Castro Neto AK, Vasconcelos RA,
et al. Carcinomatous degeneration of pilonidal cyst with sacrum destruction and invasion of the rectum. An Bras Dermatol. 2013;88(6 suppl 1):59-62.
12. Weedon D. Weedon’s Skin Pathology. London, United Kingdom: Churchill Livingstone; 2009.
13. Chintapatla S, Safarani N, Kumar S, Haboubi N. Sacrococcygeal pilonidal sinus: historical review, pathological insight and surgical options. Tech Coloproctol. 2003;7(1):3-8.
14. Steele SR, Perry WB, Mills S, Buie WD. Practice parameters for the management of pilonidal disease. Dis Colon Rectum. 2013;56(9):1021-1027.
15. Armstrong JH, Barcia PJ. Pilonidal sinus disease. The conservative approach. Arch Surg. 1994;129(9):914-917.
16. Lund JN, Leveson SH. Fibrin glue in the treatment of pilonidal sinus: results of a pilot study. Dis Colon Rectum. 2005;48(5):1094-1096.
17. Seleem MI, Al-hashemy AM. Management of pilonidal sinus using fibrin glue: a new concept and preliminary experience. Colorectal Dis. 2005;7(4):319-322.
18. Chaudhuri A, Bekdash BA, Taylor AL. Single-dose metronidazole vs 5-day multi-drug antibiotic regimen in excision of pilonidal sinuses with primary closure: a prospective, randomized, double-blinded pilot study. Int J Colorectal Dis. 2006;21(7):688-692.
19. Kronborg O, Christensen K, Zimmermann-Nielsen C. Chronic pilonidal disease: a randomized trial with a complete 3-year follow-up. Br J Surg. 1985;72(4):303-304.
20. Vogel P, Lenz J. [Treatment of pilonidal sinus with excision and primary suture using a local, resorbable antibiotic carrier. Results of a prospective randomized study]. Chirurg. 1992;63(9):748-753.
21. Rao MM, Zawislak W, Kennedy R, Gilliland R. A prospective randomised study comparing two treatment modalities for chronic pilonidal sinus with a 5-year follow-up. Int J Colorectal Dis. 2010;25(3):395-400.
22. Anderson RE, Lukas G, Skullman S, Hugander A. Local administration of antibiotics by gentamicin-collagen sponge does not improve wound healing or reduce recurrence rate after pilonidal excision with primary suture: a prospective randomized controlled trial. World J Surg. 2010;34(12):3042-3048.
23. Gencosmanoglu R, Inceoglu R. Modified lay-open (incision, curettage, partial lateral wall excision and marsupialization) versus total excision with primary closure in the treatment of chronic sacrococcygeal pilonidal sinus: a prospective, randomized clinical trial with a complete two-year follow-up. Itn J Colorectal Dis. 2005;20(5):415-422.
24. Akca T, Colak T, Ustunsoy B, Kanik A, Aydin S. Randomized clinical trial comparing primary closure with the Limberg flap in the treatment of primary sacrococcygeal pilonidal disease. Br J Surg. 2005;92(9):1081-1084.
25. Topgül K, Ozdemir E, Kiliç K, Gökbayir H, Ferahkös¸e Z. Long-term results of limberg flap procedure for treatment of pilonidal sinus: a report of 200 cases. Dis Colon Rectum. 2003;46(11):1545-1548.
26. Muzi MG, Milito G, Cadeddu F, et al. Randomized comparison of Limberg flap versus modified primary closure for the treatment of pilonidal disease. Am J Surg. 2010;200(1):9-14.
27. Unalp HR, Derici H, Kamer E, Nazli O, Onal MA. Lower recurrence rate for Limberg vs. V-Y flap for pilonidal sinus. Dis Colon Rectum. 2007;50(9):1436-1444.
28. Testini M, Piccinni G, Miniello S, et al. Treatment of chronic pilonidal sinus with local anaesthesia: a randomized trial of closed compared with open technique. Colorectal Dis. 2001;3(6):427-430.
29. Petersen S, Aumann G, Kramer A, Doll D, Sailer M, Hellmich G. Short-term results of Karydakis flap for pilonidal sinus disease. Tech Coloproctol. 2007;11(3):235-240.
30. Ersoy E, Devay AO, Aktimur R, Doganay B, Ozdog˘an M, Gündog˘du RH. Comparison of the short-term results after Limberg and Karydakis procedures for pilonidal disease: randomized prospective analysis of 100 patients. Colorectal Dis. 2009;11(7):705-710.
31. Bessa SS. Comparison of short-term results between the modified Karydakis flap and the modified Limberg flap in the management of pilonidal sinus disease: a randomized controlled study. Dis Colon Rectum. 2013;56(4):491-498.
32. Bascom J, Bascom T. Failed pilonidal surgery: new paradigm and new operation leading to cures. Arch Surg. 2002;137(10):1146-1150.
33. Gendy AS, Glick RD, Hong AR, et al. A comparison of the cleft lift procedure vs wide excision and packing for the treatment of pilonidal disease in adolescents. J Pediatr Surg. 2011;46(6):1256-1259.
A 33-year-old otherwise healthy man presented with a recurrent nodule above and slightly to the left side of the gluteal cleft (“butt crack”) (Figure 1). This lesion would occasionally drain serosanguineous fluid. The patient complained that it waxed and waned but never healed for the past 2 years. He denied any associated fevers, chills, night sweats, malaise or weight loss. On physical examination, there was an approximately 3x3 cm reddish brown nodule with central ulceration and drainage, above and slightly to the left side of the gluteal cleft. An excisional biopsy was performed.
WHAT IS YOUR DIAGNOSIS?
To learn the answer, go to page 2
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Diagnosis: Pilonidal Sinus
Pilonidal sinus disease (PSD) describes an often painful cutaneous lesion that typically occurs in the natal cleft of the sacrococcygeal area (Figure 1). A pilonidal sinus is sometimes referred to as pilonidal cyst, and when localized to the interdigital area it is referred to as barber’s interdigital pilonidal sinus. Herbert Mayo first described a pilonidal sinus in 1833 as a hair-containing sinus,1 but the term “pilonidal” was coined in 1880 by R.M. Hodges to suggest a nest of hair (Latin: pilus = hair and nidus = nest). During World War II, this condition commonly occurred in jeep drivers due to repeated chafing, leading to the nickname “jeep seat disease.”
PSD occurs in about 0.7% of the population, with an incidence of 25 in 100,000. Peak age of presentation ranges from 15 to 30, with the mean age being 20.2 This condition affects males twice as much as females, with 80% of the afflicted patients being male.3 This condition is also more common in Caucasians than African Americans or Asians due to differences in characteristics and growth patterns of hair.4 Men are at a higher risk due to their more hirsute nature.5 Other risk factors for PSD include thick skin, obesity, deep gluteal cleft, sedentary occupation and local irritation or trauma.6,7
Etiology and Pathogenesis
Understanding of this condition has been filled with controversies, particularly related to the etiology. PSD was initially thought to be a congenital condition and classified as a dermoid cyst. This theory suggests that the lesion developed from an infection of an epithelialized tract along the natal cleft, which occurs from the absence of primitive ectoderm fusion.7
In contrast, the acquired theory is more widely accepted as the pathogenesis of PSD. Several hypotheses have been proposed to explain the etiology, all accounting for the particular characteristics associated with the anatomic region, such as the pressure effects and shearing force.
The current view of PSD starts with a keratin plug in the natal cleft hair follicle resulting in an infection, which increases its risk of becoming distended and obstructed. These dilated follicles rupture in the subcutaneous tissues, producing an acute or chronic inflammation along with the development of an abscess or a tract (Figure 2). The hair follicle and cellular debris that accumulate in the skin could further enhance the inflammatory reaction by acting as a foreign body.8,9 The material accrued can become infected with bacteria, which has 2 important impacts. First, toxins from the bacteria can break down proteins and liquefy tissues. Second, as part of the inflammatory process, the body floods the area with neutrophils and macrophages. The inflammatory reaction to the damaged follicle and surrounding tissue can become a chronic condition over time. PSD is prone to recurrent infections due to the presence of moisture, bacteria, hair and friction.10 Although malignant transformation is rare, cases of squamous cell carcinoma and verrucous carcinoma have been reported.11
In addition, PSD is part of group of diseases called follicular occlusion syndrome, which includes hidradenitis suppurativa (acne inversa), acne conglobata (severe nodulocystic acne) and dissecting cellulitis (perifolliculitis capitis abscedens et suffodiens). Commonly coexistent, these conditions are defined by a similar process in which hair follicles become blocked with keratin and then rupture, resulting in an inflammatory skin condition. PSD is often found in patients with hidradenitis suppurativa. Because both types of lesions can occur in the natal cleft, it is important to distinguish the 2 as the treatments are different.12
Clinical Features
Patients with PSD may present with small abscesses or pits on or off the midline, at the level of the coccyx, about 4 cm to 10 cm from the anus. These patients are typically heavy hirsute males and perspire profusely. A malodorous discharge or occasional bleeding from the lesion may be present. Also, a history of prior treatment of PSD is common due to its recurrent nature. The main complaint is pain, but fever may be present in rare cases. One or several pits that communicate with a deeper cavity by an epithelialized tract generally accompany an infected pilonidal sinus.7
A patient with PSD can present in 1 of the following stages:
1. Asymptomatic – This is usually discovered during routine examination.
2. Acute inflammation, infection and abscess formation – Patient presents with pain as a result of swelling and possibly purulent discharge. Examination can reveal cellulitis over the natal cleft, with the patient intolerant to touch to the afflicted region.
3. Chronic disease – Patient presents with chronic pain, recurrent infection over a 2-year period, and possibly multiple affected sites. Signs of inflammation and swelling can also be observed.
4. Complex or recurrent disease – This stage is usually related to re-infection of neighboring hair follicles or from postoperative wound infection.7,10
Histopathology
Histologic examination of a pilonidal sinus shows a sinus tract lined by granulation tissue and in some areas, stratified squamous epithelium (Figure 3). The sinus is infiltrated by neutrophils, lymphocytes, plasma cells and sometimes hemosiderin-laden macrophages. The tract leads to a bulbous expansion in the lower dermis and subcutaneous tissue where a chronic abscess cavity lies, which contains a hair follicle in 50% to 75% of cases. Foreign body granulomas in the vicinity of the hair may be present.12,13
Differential Diagnosis
In some cases, a pilonidal sinus can be confused with other inflammatory lesions with similar histological features such as granulation tissue and foreign-body giant cells. Distinguishing factors between these conditions often relies on clinical expertise.
- Hidradenitis suppurativa is a relapsing disorder of the folliculopilosebaceous units characterized by abscesses, epidermoid cysts and sebaceous cysts that occur on the buttocks. These cysts can sometimes contain hair shafts.
- Anal fistula is a perianal extension from an internal opening within the anal canal and can present with anal mucus discharge.
- Pyoderma gangrenosum consists of a rare, chronic neutrophilic dermatosis that may contain hair shafts.
- Perirectal abscess results from an infection that occurs as a painful erythematous lump near the anus. It usually presents with pus and can resolve on its own.
- Furunculosis is a deep infection of hair follicles that differs from a pilonidal sinus due to its pathogenesis.
- Anal fissure presents as a small oval-shaped tear in skin along the natal cleft. This lesion typically causes severe pain and bleeding with bowel movements.
Other granulomatous conditions occurring in the gluteal cleft such as Crohn’s disease, mycetoma, perianal tuberculosis and syphilitic granuloma can present similarly to PSD.12,13
Treatment
Due to the wide spectrum of PSD presentations, treatment course depends on the clinical features and ranges from simple excision and drainage to extensive flap procedure. The American Society of Colon and Rectal Surgeons (ASCRS) made several recommendations in 2013 regarding the treatment for various presentations of PSD (Tables 1 and 2).
Asymptomatic lesions typically do not require treatment. In the absence of an abscess, gluteal cleft shaving may be employed for both acute and chronic PSD as a primary or adjunct therapy. Because most studies on gluteal cleft shaving have used an arbitrary manner and method, effective frequency and extent of shaving have not been systematically studied. Due to unclear efficacy of topical or systemic antibiotics, ASCRS recommends these agents as adjunct treatment for patients with significant cellulitis, immunosuppression or concomitant systemic illness.14
Acute primary or recurrent PSD accompanied by abscess should be treated with incision and drainage. In patients undergoing incision and drainage, those who received curettage showed greater rates of complete healing and lower incidences of recurrence than those who did not receive curettage. Based on the surgeon and patient preference, recommended surgical options for the treatment of PSD included excision and primary repair, excision with healing by secondary intention and excision with marsupialization. In cases of complex and multirecurrent chronic PSD where other methods have failed, flap-based procedures including rhomboid flap, Karydakis flap, cleft-lift technique and V-Y advancement may be performed.14
Our Patient
Biopsy results showed a sinus tract lined by stratified squamous epithelium and granulation tissue. Inflammatory cells including neutrophils, lymphocytes and plasma cells infiltrated the sinus, and a few hemosiderin-laden macrophages were also present. The sinus led to an abscess cavity in the lower dermis, which contained a hair follicle and foreign-body granulomas.
Due to the length and recurrent nature of the PSD, our patient was referred to a general surgeon for an excision and repair procedure. Involved skin and subcutaneous tissue were excised using electrocautery after administration of local anesthetics. A funnel-shaped excision was made deep to the incision in order to completely remove the track only. The wound was washed, cleaned and closed with gauze. The patient was followed at the surgery clinic for postoperative care and then with us regularly.
Conclusion
Pilonidal sinus is a painful lesion that typically occurs in the natal cleft. This lesion results from a keratin plug in a hair follicle becoming infected, rupturing the subcutaneous tissue, becoming acutely or chronically inflamed, or developing into an abscess or a tract. Due to its pathogenesis, this lesion has a wide spectrum of presentations ranging from asymptomatic lesions to a complex and recurrent abscess. Various treatments are available for PSD depending on the presentation.
Ms. Chen is a student at Downstate SUNY College of Medicine in Brooklyn, NY.
Dr. Liu is with department of dermatology at State University of New York Downstate in Brooklyn, NY.
Mr. Malik is a student at State University of New York Downstate College of Medicine in Brooklyn, NY.
Mr. Patel is a student at Albert Einstein College of Medicine in Bronx, NY.
Dr. Khachemoune, section editor of Derm DX, is with department of dermatology at State University of New York Downstate in Brooklyn, NY, and Veterans Affairs Medical Center Dermatology Service in New York, NY.
Disclosure: The authors report no relevant financial relationships.
References
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24. Akca T, Colak T, Ustunsoy B, Kanik A, Aydin S. Randomized clinical trial comparing primary closure with the Limberg flap in the treatment of primary sacrococcygeal pilonidal disease. Br J Surg. 2005;92(9):1081-1084.
25. Topgül K, Ozdemir E, Kiliç K, Gökbayir H, Ferahkös¸e Z. Long-term results of limberg flap procedure for treatment of pilonidal sinus: a report of 200 cases. Dis Colon Rectum. 2003;46(11):1545-1548.
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27. Unalp HR, Derici H, Kamer E, Nazli O, Onal MA. Lower recurrence rate for Limberg vs. V-Y flap for pilonidal sinus. Dis Colon Rectum. 2007;50(9):1436-1444.
28. Testini M, Piccinni G, Miniello S, et al. Treatment of chronic pilonidal sinus with local anaesthesia: a randomized trial of closed compared with open technique. Colorectal Dis. 2001;3(6):427-430.
29. Petersen S, Aumann G, Kramer A, Doll D, Sailer M, Hellmich G. Short-term results of Karydakis flap for pilonidal sinus disease. Tech Coloproctol. 2007;11(3):235-240.
30. Ersoy E, Devay AO, Aktimur R, Doganay B, Ozdog˘an M, Gündog˘du RH. Comparison of the short-term results after Limberg and Karydakis procedures for pilonidal disease: randomized prospective analysis of 100 patients. Colorectal Dis. 2009;11(7):705-710.
31. Bessa SS. Comparison of short-term results between the modified Karydakis flap and the modified Limberg flap in the management of pilonidal sinus disease: a randomized controlled study. Dis Colon Rectum. 2013;56(4):491-498.
32. Bascom J, Bascom T. Failed pilonidal surgery: new paradigm and new operation leading to cures. Arch Surg. 2002;137(10):1146-1150.
33. Gendy AS, Glick RD, Hong AR, et al. A comparison of the cleft lift procedure vs wide excision and packing for the treatment of pilonidal disease in adolescents. J Pediatr Surg. 2011;46(6):1256-1259.
