Malignant Melanoma of Soft Tissue: An Unusual Presentation of Clear Cell Sarcoma of the Heel-A Case Report

Abstract

Clear cell sarcoma (CCS) is a rare malignant soft tissue tumor first described by Enzinger in 1965. It demonstrates melanocytic differentiation and shares histological and immunohistochemical similarities with malignant melanoma, which often makes diagnosis challenging. CCS commonly arises from tendons and aponeuroses of the distal extremities, particularly around the foot and ankle. It typically presents as a slow-growing painless mass but may occasionally present atypically, resulting in delayed diagnosi.

We report a case of a 62-year-old female presenting with a chronic non-healing ulcer over the left heel, initially treated as a plantar corn. Incision biopsy revealed clear cell sarcoma confirmed by immunohistochemistry showing positivity for S-100, HMB-45, and vimentin. Imaging studies demonstrated a localized soft tissue lesion without bone involvement or distant metastasis. The patient underwent wide local excision with sentinel lymph node biopsy followed by dermal reconstruction. Histopathology confirmed clear cell sarcoma with tumor-free margins and negative sentinel lymph nodes.

This case highlights the diagnostic challenges associated with atypical presentations of CCS and emphasizes the importance of early biopsy and surgical management to improve outcomes.