Sclerosing Dermatofibrosarcoma Protuberans: A Possible Diagnosis When a Small Biopsy Shows Sclerotic Fibroma-Like Features.

Dermatofibrosarcoma protuberans (DFSP) is a neoplasm of intermediate malignancy with high local recurrence rates. The sclerosing variant is characterized by the presence of sclerotic areas in more than 50% of tumors and is rarely reported. In this report, we describe a case of sclerosing DFSP with areas histopathologically resembling sclerotic fibroma, where the initial biopsy tissue presented a diagnostic challenge. A 77-year-old man presented with a 2-cm firm, erythematous nodule on the chest. A punch biopsy revealed plywood-like sclerosis and spindle cells with a vaguely storiform pattern. The tumor cells were positive for CD34. Sclerotic fibroma and DFSP were considered differential diagnoses. Subsequent excisional biopsy revealed that the tumor comprised 3 different histopathological areas: classic DFSP, sclerotic fibroma-like, and giant cell fibroblastoma-like. This report highlights the importance of reevaluating the clinical context and excision for further characterization.