Atypical Ulcer Arising on Stasis Dermatitis: Achromic Melanoma

Occurring as a result of chronic venous insufficiency, stasis dermatitis (SD) usually involves the medial part of the lower leg or ankle. Stasis dermatitis is associated with inflammation, edema, and areas that are atrophic, variably pigmented, and scaly. An ulcer is prone to develop with the progression of the stasis and the inflammatory process. In cases of chronic inflammation such as chronic wounds, scars, radiotherapy, burns, osteomyelitis, and fistulas, neoplastic ulcers (Marjolin ulcers) can develop.¹

Squamous cell carcinoma and basal cell carcinoma are the most frequent subtypes of cancers associated with skin ulcers and SD.^1,2 Lymphomas and other cancers have also been described in skin stasis of the lower limbs.³ Despite this, such circumstances are uncommon.¹ Achromic melanoma is a rare form of pigmentless melanoma, and it is most frequently located on the sole of the foot. Ulcerated achromic melanoma of the lower limbs can be easily confused with a vascular wound, representing an important dermatological pitfall. Diagnosis is often delayed and is associated with a poor prognosis.⁴

A 70-year-old female presented to the authors' department with a painless ulcer on the right leg that had been present for 1 year. The patient had venous insufficiency, and presence of SD on the right leg was evident; of note, the patient did not have diabetes or other systemic comorbidities. The patient described the development of an erythematous, painless, and progressively nonhealing ulcer in the middle of SD, which had developed 12 months previously. The ulcer was treated by a different health care provider with advanced dressings based on clinical features of the wound and perilesional skin as well as treated with a multicomponent bandage for venous insufficiency.⁵

Upon clinical examination, an ulcer with a 2-cm diameter and irregular, pigmented borders was noted (Figure 1A). Doppler ultrasound study confirmed venous insufficiency. Dermoscopy revealed the presence of red globules, a gray-to-blue veil, irregular vessels, and the remains of a pigmented ridge pattern (Figure 1B). A punch biopsy confirmed a melanocytic lesion. Histological analysis showed infiltration of atypical melanocytes in the dermis, 2 mitoses, and ulceration (Figure 2A). This diagnosis was confirmed by positive immunochemistry for MART-1 (Figure 2B). The melanoma was removed with 2-cm free margins, and an autologous skin graft excised from the inner thigh was applied. Following the guidelines of the American Joint Committee on Cancer,⁶ a sentinel lymph node biopsy procedure was performed. The result was negative for lymph node involvement. No disease recurrence was reported during the 18 months of dermatological and oncological follow-up.

Although leg ulcers can be misdiagnosed as vascular ulcers, atypical clinical presentation of a leg ulcer may indicate malignancy. In such cases, a diagnostic biopsy procedure is recommended. Atypical ulcers are characterized by atypical features of the wound bed, wound edges, perilesional skin, and wound localization. Atypical ulcers fail to heal despite standard therapy. A diagnostic biopsy procedure is recommended in the presence of these features and/or suspected malignancy. However, if the case is not evident, multiple biopsy procedures on the area with the most atypical appearance or pigment residues are preferred.⁷ Khoobyari et al⁸ highlighted the importance of performing biopsy procedures to diagnose chronic ulcers correctly. Gil et al¹ reported basal cell carcinoma and squamous cell carcinoma as the most common malignancy diagnoses in nonhealing wounds. The case report¹ described a very rare case of malignant melanoma (MM) that arose within the context of SD. This case had initially been misdiagnosed because the skin was atrophic and easily ulcerated, and the peripheral brown pigmentation might have been interpreted as the result of extravasated red blood cells. The authors conducted a comprehensive clinical dermoscopic evaluation, leading to the correct diagnosis.¹ The vigorous appearance of the wound bed is typical of neoplastic ulcers, and perilesional pigmentation is characteristic of achromic melanoma.⁵ The wound had previously been treated for 12 months with dressings and bandages. Lack of healing with standard therapies after 6 weeks is another important indication for histological investigation. In 1997, Blessing⁹ reported the suspicion of MM in SD, later confirmed by its dermoscopic features, and described the challenges in the histological diagnosis within this context.

These types of lesions can be easily overlooked, and the features of SD must be differentiated from regression. This report draws attention to the possibility that MM may also develop in the context of SD, and secondary prevention is critical for a better prognosis.¹⁰

The main limitation of the study is that it is a single case report.

The current case highlights the importance of clinically evaluating and conducting a biopsy procedure of a chronic, atypical, nonhealing ulcer. When atypical features, perilesional pigmentation, and a lack of response to standard therapies of ulcers associated with SD occur, one or more biopsies are mandatory to rule out achromic melanoma.

Authors: Agata Janowska, MD¹; Giulia Davini, RN¹; Cristian Fidanzi, MD¹; Valentina Dini, MD, PhD¹; Barbara Loggini, MD, PhD¹; Giovanni Bagnoni, MD²; Marco Romanelli, MD, PhD¹; and Angelo D’Erme, MD, PhD²

Affiliations: ¹University of Pisa, Pisa, Italy; ²Ospedale Civile di Livorno, Livorno, Italy

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

ORCID: Giulia Davini, 0000-0001-7545-649X; Valentina Dini, 0000-0002-8537-1999; Cristian Fidanzi, 0000-0002-9189-9204; Agata Janowska, 0000-0002-2271-3859; Marco Romanelli, 0000-0002-4127-0141

Correspondence: Agata Janowska, MD, Assistant Professor, University of Pisa, Dermatology, Via Roma 67, Pisa, Pisa 56126 Italy; dottoressajanowska@gmail.com