Misdiagnosed Malignant Tumor on an Ischemic Limb

Introduction. Acral lentiginous melanoma (ALM) is a rare variety of melanoma typically located on distal areas of the body. Due to its presentation, it can be confused with a vascular ulcer. Case Report. The authors present the case of a 68-year old man who smokes with a history of hypertension, diabetes, and dyslipidemia, who was referred to the vascular clinic with complaints of intermittent claudication and a developing ulcer on his heel. After formulating an accurate wound care plan and performing revascularization surgery, the ulcer did not heal. At this point, the wound was biopsied and melanoma diagnosis was confirmed. After melanoma surgery, direct closure of the wound with a split-thickness skin graft was performed. Conclusions. Despite its rare pathology, misdiagnosis of ALM may prolong initiation of appropriate treatment and reduce the overall survival rate. Biopsies should be performed on nonhealing ulcers despite appropriate wound management and/or revascularization procedures.

Acral lentiginous melanoma (ALM), a rare variety of melanoma first described by Reed,¹ typically is located on distal areas of the body. Due to its presentation, it can be confused with a vascular ulcer on patients with diabetes or ischemia. It should be suspected on atypical wounds and those that do not heal despite appropriate wound care management and/or after surgical revascularization.

Herein, the authors report the case of a man who presented with melanoma misdiagnosed as an ulcer to draw awareness of the possible resemblance in presentation of ALM to that of an ulcer.

The authors present the case of a 68-year- old man who smoked (1 pack/day) with a history of hypertension, diabetes, and dyslipidemia. He was referred to the vascular clinic of Hospital de Cabueñes (Gijon, Asturias, Spain) due to intermittent claudication and development of a left heel ulcer.

Upon physical examination, the patient had a left limb femoropopliteal obstruction with a granulated ulcer measuring 4 cm x 3 cm, with no sign of infection. At this point, conservative management with periodical cures (treatment with topical dressings, ie, alginate dressings) under supervision in the clinic was chosen. Despite a 12-month accurate wound care regimen, the ulcer did not respond to treatment and was observed for further development. Due to the persistence of the ulcer, the authors suspected osteomyelitis. The patient underwent a magnetic resonance imaging (MRI) scan that revealed no sign of an underlying infection.

The lack of response to the conservative treatment and absence of an infectious source prompted an arteriographic study 2 weeks after the MRI (12.5 months after initial presentation), which showed a superficial femoral artery obstruction with first popliteal portion recanalization (Figure 1 and Figure 2). Following these findings, revascularization surgery (femoropopliteal bypass) was performed 1 week after arterography (12.75 months after initial presentation). After the procedure, the patient recovered distal pulses with ankle-brachial index (ABI) normalization (prior to bypass ABI = 0.7).

Despite surgical intervention, the ulcer had worsened and rapidly developed exophytic hypergranulation tissue (Figure 3). A wound biopsy was performed 10 to 15 days postoperatively (~13 months after initial presentation), which confirmed a diagnosis of ALM. The patient underwent a computed tomography scan that showed no disease dissemination.

The patient was referred to the hospital’s dermatology department where they decided to excise the tumor with 2-cm margins, covering the incision with a split-thickness skin graft. Following the skin graft, the ulcer had achieved full wound closure without the development of any new ulcers at about 14 to 15 months post initial presentation. No adjuvant chemotherapy or radiotherapy was necessary.

Melanoma is a rare, lethal cutaneous tumor that represents 4% of total skin cancers but causes 80% of total skin cancer deaths.² Up to 15% of melanomas are located on the foot, which worsens its prognosis.^3,4 Of the 4 cutaneous melanoma subtypes, ALM is the least common (1%–7%); however, it is the most commonly diagnosed subtype on the foot. It has predilection for distal areas of the body (palms, soles, and subungual areas).⁵

Performed studies have shown that time between initial injury and accurate diagnosis is 13.5 months.⁶ Considering a patient with diabetes or ischemia has a predisposition to develop foot ulcers, this kind of injury may have a greater risk of misdiagnosis in this patient population.

Even with a rare pathology, ALM has a potential for mortality. Misdiagnosis can delay accurate treatment for 12 months, increase tumor thickness, and reduce the 5-year survival rate up to 68.9%.⁷ Because of this, physicians specialized in the management of vascular ulcers should be aware of the possible resemblance in presentation of ALM to that of an ulcer. It is recommended that a biopsy should be performed on all nonhealing ulcers that have failed to respond appropriately to wound care treatment⁸ or revascularization procedures.

Authors: Luis Angel Suarez Gonzalez, PhD; Pablo Del Canto Peruyera, PhD; Javier Cerviño Alvarez, PhD; and Luis Javier Alvarez Fernandez, PhD

Affiliation: Hospital de Cabueñes, Gijon, Asturias, Spain

Correspondence: Luis Ángel Suárez González, PhD, Hospital de Cabueñes, Vascular Surgery, Camin de los Campos, Gijon, Asturias 33000 Spain; luis_angel_suarez@hotmail.com

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