Dermatofibrosarcoma Protuberans: A Case Report

Dermatofibrosarcoma protuberans (DFSP) is a rare malignant tumor of the skin and soft tissues that typically arises in the dermis and subcutaneous tissue, sparing the epidermis. It is a fibroblastic neoplasm characterized by the collagen type I alpha 1 gene with the platelet-derived growth factor B-chain gene fusion. Although it can occur at any age, it is most frequently diagnosed between 30 and 50 years of age. Clinically, DFSP presents in a wide variety of forms, ranging from plaques or small nodules to large, irregular masses; it usually manifests as a firm, multinodular, slow-growing lesion, and the term "protuberans" refers to the nodules that form beneath the skin. Because it can easily be mistaken for benign lesions such as dermatofibroma, keloid, lipoma, or even an abscess, diagnosis is often delayed, particularly when the index of suspicion is low. Complete surgical resection remains the cornerstone of treatment, with options including wide local excision and Mohs micrographic surgery with meticulous assessment of deep and peripheral margins. We present the case of a 49-year-old Mexican woman whose lesion was initially excised as a presumed lipoma and histologically interpreted as a histiocytoma with features of a keloid scar; after recurrence, a second biopsy confirmed DFSP. This case highlights the importance of histopathological evaluation of atypical or treatment-resistant scar-like lesions.