Leiomyosarcoma of soft tissue masquerading as infected sebaceous cyst: a rare case report

Leiomyosarcomas are aggressive malignant neoplasms with a high propensity for local recurrence & distant metastasis. Approximately two-thirds of Leiomyosarcoma occur in retroperitoneum/abdomen, while the localized soft tissue variant involving the extremities & trunk is rare. They exhibit varied clinical presentations, such as a painful, progressively enlarging mass associated with overlying skin changes, making preoperative diagnosis challenging. We report an unusual case of Leiomyosarcoma of soft tissue in a 46-year-old male presenting with painful swelling in the left posterior aspect of shoulder mimicking sebaceous cyst. The patient underwent surgical excision and combined histopathological & immunohistochemical analysis confirmed High-grade Leiomyosarcoma, Grade 3. As many of these lesions are potentially curable, the wide local excision & regular follow up stands the mainstay treatment.