Rare Presentation of Squamous Cell Carcinoma of the Foot in a Noncompliant HIV+ Patient

Introduction. Squamous cell carcinoma (SCC) is most commonly found on sun-damaged skin and less often occurs on the toes and feet. Case Report. A 41-year-old man with a history of human immunodeficiency virus and asthma, who had received highly active antiretroviral therapy for 7 years while incarcerated, presented to the emergency department with a primary SCC of the left foot with inguinal lymph node metastasis. The patient underwent a left foot transmetatarsal amputation; due to noncompliance, he underwent a below-the-knee amputation 17 days later as a result of surgical findings and extent of infection. The surgical site fully healed without further complications. The patient now has phantom limb pain of the left leg, sees oncology for palliative marijuana use, and refuses the recommended positron-emission tomography/computed tomography scan for completion of cancer staging. Conclusions. This case shows the importance of patient compliance and timely treatment of SCC and surgical wounds in an immunosuppressed individual. 

Squamous cell carcinoma (SCC) is less commonly found in the foot, with 84% found in the head and neck.¹ Of cases specifically involving the lower extremity, only 2.3% involve the foot.¹ It is most commonly found on sun-damaged skin.^1-3 In addition, immunosuppression may contribute to carcinogenesis by reducing host surveillance and increasing the susceptibility of keratinocytes to infection and transformation by oncogenic viruses.^2,3

In the case presented herein, pathology confirmed SCC diagnosis of the left forefoot in a patient with human immunodeficiency virus (HIV) and noncompliance with his postoperative surgical treatment that likely contributed to an undesirable outcome.

A 41-year-old man with a history of HIV and asthma, who was recently released prior to presentation from 7 years of incarceration where he received highly active antiretroviral therapy (HAART), presented to the emergency department (ED) in September 2015 with concerns about a painful mass on his left foot measuring 4.9 cm x 5.2 cm. The patient reported that the growth started as a small, rough area at the juncture between the fourth and fifth toes. Radiographic imaging of the left foot revealed an increased irregular soft tissue density overlying the dorsum of the left foot at the level of the third, fourth, and fifth phalanges, consistent with a fungating wound, in addition to soft tissue edema without underlying osseous involvement. He was diagnosed with a fungal infection with superimposed bacterial infection and discharged home with a prescription for terbinafine 250 mg daily for 14 days, amoxicillin/clavulanate acid 500/125 mg to be taken every 12 hours for 10 days, and a povidone-iodine foot dressing; he also received a postoperative shoe and crutches, a 1-week follow-up appointment with podiatry for reevaluation, and a referral for a new primary care physician to manage his antiretroviral therapy. At that time, he was no longer compliant with HAART and his CD4 count was 460/uL with a viral load of 300 copies/mL.

The patient presented to podiatry 2 weeks after his ED visit. He believed the lesion had been present for about 1 month prior to presentation to the podiatry clinic and started as a rash. He thought it was a wart. Pedal examination demonstrated palpable dorsalis pedis and posterior tibial arteries, normal sensation, and a fungating mass measuring 4.9 cm x 5.2 cm on the dorsal aspect of the left foot involving toes 3 to 5 and the intertriginous space between the fourth and fifth digits with maceration (Figures 1, 2). Moccasin distribution of tinea pedis was noted. An incisional biopsy of the lesion was obtained using a number 15 blade and sent for pathology evaluation. Follow-up evaluation was delayed for 1 month secondary to 2 missed appointments by the patient. Pathology was consistent with SCC in situ, with the possibility of invasive carcinoma in adjacent regions. He then was referred to plastic surgery to evaluate reconstructive options.

At the plastic surgery consult 2 months after initial presentation to the ED, the large fungating mass had increased in size, measuring 5.0 cm x 5.3 cm, and was now noted over the dorsal surfaces of toes 2 to 5. In addition, while no palpable popliteal nodes were found, palpable shotty, mobile, and nontender inguinal nodes were noted. A punch biopsy of the foot was again taken for question of likely invasive SCC prior to determining resection margins. The pathology results reported superficially invasive, poorly differentiated SCC with positive lateral margins (Figure 3). Chest x-ray was negative for metastatic spread to the lungs. A whole body positron-emission tomography/computed tomography (PET/CT) scan was ordered to evaluate for metastasis, but the patient did not show up for the study.

A left foot transmetatarsal amputation (TMA) was performed by the podiatric surgery team in conjunction with a left femoral sentinel lymph node biopsy by plastic surgery 9 weeks after initial presentation to the ED. The sentinel node was involved with carcinoma on frozen section, prompting a complete inguinal/femoral node dissection. The remaining 18 lymph nodes were negative for malignancy. The primary site pathology noted a left foot with invasive 6.9-cm SCC, keratinizing type, and moderately differentiated with underlying bone uninvolved and negative margins. Both surgical sites were closed, and a drain was inserted to the groin region. The patient was admitted overnight for pain control but discharged without complication the following day.

He attended his postoperative clinic visit with plastic surgery 2 days after discharge with normal healing. However, he did not attend his 1-week postoperative podiatry clinic appointment or his 1-week postoperative infectious disease appointment, and his dressing remained unchanged since the time of the operation.

The patient presented to the ED 11 days postoperatively with a white blood cell count of 32.1 with left shift, heart rate of 135, temperature of 100.4°F, a left groin hematoma, and gas gangrene at the surgical wound of his left foot (Figure 4). He complained of continued pain in the foot. He was emergently brought to the operating room for a left foot incision and drainage with revisional TMA by the podiatric surgery team in conjunction with an evacuation of a left groin hematoma by plastic surgery. Microbiology of the foot revealed Enterococcus and Bacteroides fragilis, and microbiology of the groin demonstrated Escherichia coli. He was started on intravenous vancomycin 1 g every 12 hours and ceftazidime 1 g every 8 hours, and oral metronidazole 500 mg every 8 hours with positive effects.

Due to surgical findings and the extent of infection, a below-the-knee amputation (BKA) was recommended and performed 6 days later (12 weeks after initial presentation to the ED).

Both surgical sites have since healed without further complication. He was started on ATRIPLA (Gilead Sciences, Inc, Foster City, CA) by infectious disease to treat his HIV. Oncology follow-up appointments were recommended, but he has continued to refuse the recommended PET/CT scan for completion of staging. The patient continues to have phantom limb pain at the BKA site along with left leg pain, and he continues to follow with oncology for palliative use of marijuana.

Squamous cell carcinoma is a malignant neoplasm less commonly found on the foot than other sites with more sun exposure, and it is a malignant epithelial tumor that arises from keratinizing epidermal cells and can have many different levels of differentiation and aggressiveness.^2,3 The 2 main types of SCC are in situ (SCCIS) and invasive SCC. Squamous cell carcinoma in situ does not invade through the basement membrane of the dermoepidermal junction and may present clinically as solitary or multiple macules, papules, or plaques that may be hyperkeratotic or scaling.^2,3 In addition, SCCIS can progress into invasive lesions where atypical keratinocytes invade the dermis layer of the tissue, often appearing nodular and showing variable keratin production that may ulcerate. Nodule formation or onset of pain or tenderness within SCCIS suggests progression to invasive SCC.^2-4 Lymph node metastasis can occur without demonstrable invasion and lead to metastatic dissemination from lymph nodes.³ Further, SCC in the skin has a metastatic rate of 3% to 4%.³ Clinically, undifferentiated SCC is typically soft and has no hyperkeratosis, while differentiated SCC is hard on palpation and has hyperkeratosis.³ Undifferentiated SCC and SCC in immunosuppressed individuals are more aggressive with a greater incidence of metastasis.³

Commonly accepted methods of treatment for SCC without metastatic dissemination include topical 5-fluorouracil, imiquimob, methotrexate, cryosurgery, surgical excision, and Moh’s micrographic surgery.^2-5 The choice of treatment is dependent on the nature and location of the lesion.^2-5 In human papillomavirus-induced SSCIS in HIV/AIDS patients, lesions may often resolve completely with successful antiretroviral therapy and immune reconstitution.³

The case reported herein involved invasive SCC of the left forefoot in an immunosuppressed patient with metastasis to the femoral lymph nodes. His clinical and pathological findings warranted aggressive treatment with surgical excision, amputation, and complete inguinal/femoral node dissection for immediate eradication of SCC. Noncompliance with appointments led to a delay in treatment of the SCC and additionally led to a delay in detection of infection to the postoperative TMA surgical wound, which ultimately resulted in a BKA. It is imperative to stress the danger of aggressive SCC in patients who are immunocompromised, such as patients with HIV or chronically immunosuppressed organ transplant recipients. These patients may be most at risk for life-threatening, highly virulent SCC. Ultimately, noncompliance plays a crucial role in threats to both limb and life for patients with immune compromise and skin malignancies.

Affiliations: Yale Podiatric Medicine and Surgery Residency Program, New Haven, CT; Yale School of Medicine, Section of Plastic Surgery, New Haven, CT; Department of Orthopaedics and Rehabilitation, Yale School of Medicine; and Yale Podiatric Foot and Ankle Surgery Residency Program, New Haven, CT

Correspondence: Shelly D. Sedberry, MS, DPM, Shoal Creek Foot and Ankle Center, 1801 West 32nd Street, Building C, Suite 102, Joplin, MO 64804;
sedberry@shoalcreekfac.com

Disclosure: The authors disclose no financial or other conflicts of interest.