Rapidly enlarging dermatofibrosarcoma protuberans: a case report of atypical presentation with diagnostic complexities and reconstructive challenges.

Introduction and Importance: Dermatofibrosarcoma protuberans (DFSP) is a rare, low-grade dermal sarcoma known for local aggressiveness and high recurrence despite low metastatic potential. Early diagnosis and complete surgical excision with negative margins are critical for management. Reconstruction can be challenging, especially for large lesions. We report a rare case of rapidly enlarging DFSP over the lower chest-epigastric junction, complicated by diagnostic delays and complex reconstruction. Case Presentation: A 45-year-old man presented with a 4-5-month history of progressive midline chest swelling, low-grade fever, discomfort, and weight loss. Imaging revealed a vascular subcutaneous mass abutting the sternum. Fine needle aspiration cytology (FNAC) and biopsy remained inconclusive, delaying definitive diagnosis. Wide local excision with 3 cm margins created a 19 × 21 cm midline defect, requiring further extension based on frozen section. Reconstruction utilized a right paraumbilical perforator-based fasciocutaneous flap for primary closure. Final histopathology confirmed DFSP with clear margins and no high-grade transformation. Postoperative recovery was uneventful. Clinical Discussion: This case posed diagnostic and surgical challenges due to atypical presentation over the midline anterior abdominal wall, rapid enlargement of an otherwise indolent lesion, and inconclusive workup. Intraoperatively, the lesion's vascularity and ill-defined margins prolonged surgery with significant blood loss. Multidisciplinary collaboration and intraoperative flexibility remained critical for achieving optimal oncologic and reconstructive outcomes. Conclusion: Early diagnosis, multidisciplinary planning, and tailored reconstructive strategies are vital in managing extensive, anatomically complex DFSP. This case highlights the importance of diagnosing rare presentations earlier with individualized, lesion-specific surgical approaches in achieving both functional and oncologic success.