Rapidly Evolving Cervical Dermatofibrosarcoma Protuberans With Deep Muscle Infiltration: A Rare and Aggressive Presentation.

Dermatofibrosarcoma protuberans (DFSP) is a rare, low-grade sarcoma that typically presents as a slow-growing cutaneous nodule or plaque. We report a highly unusual case of DFSP involving the neck, which demonstrated rapid enlargement, necrosis, and deep muscle infiltration. A 45-year-old man presented with a large, bleeding cervical tumor that had evolved over two years. Imaging revealed extensive involvement of the neck and shoulder musculature without distant metastasis. Histopathologic evaluation confirmed the diagnosis of DFSP. Given the tumor's inoperability, treatment with imatinib was initiated, resulting in marked tumor regression. This case highlights an atypical presentation of DFSP in terms of both location and clinical behavior. It underscores the importance of repeated histologic assessment in the face of rapid progression, the role of imaging in surgical planning, and the value of targeted therapy when surgical options are limited.