Trauma-Induced Melanocyte Implantation Leading to Subcutaneous Melanoma
Source: Dermatology Times, February 2025
Trauma-induced melanocyte implantation can lead to subcutaneous melanoma, mimicking melanoma of unknown primary but with distinct diagnostic criteria.
Melanoma is often challenging to diagnose when it lacks a visible primary cutaneous lesion. In such cases, melanoma of unknown primary (MUP) is often considered.1 MUP occurs when melanoma metastasizes to sites such as the subcutaneous tissue or lymph nodes without any obvious primary lesion on the skin.1 This diagnosis carries a favorable prognosis compared with cutaneous metastatic melanoma.1 This report presents a unique case of melanoma in a 66-year-old male patient, in which the melanoma developed subcutaneously after the traumatic removal of a preexisting epidermal nevus, which could initially suggest MUP but does not meet the criteria for this condition.
Case Presentation
A 66-year-old non-Hispanic Caucasian man presented with a slow-growing, nontender lump in his left groin. He denied systemic symptoms such as fever, weight loss, or nausea. His medical history included hypertension, dyslipidemia, and obesity. An ultrasound-guided needle biopsy of the groin lump revealed stage III malignant melanoma. The histopathological analysis confirmed melanoma, with strong S-100, SOX10, and MART-1 staining, indicative of melanoma cells.