Subcutaneous Axillary and Scalp Metastases from Non-Gynecological Retroperitoneal Leiomyosarcoma: An Unusual Presentation After Surgical Resection

Retroperitoneal leiomyosarcomas are rare sarcomas, with an incidence of less than 2 per million population. Cutaneous metastases from sarcoma account for only 1-2.6% of metastatic skin lesions. Cutaneous and subcutaneous metastasis from retroperitoneal leiomyosarcoma is a very rare entity. We present a case of 72-year-old male with scalp nodule and subcutaneous swelling in left posterior axillary fold. Fine needle aspiration cytology from both these sites revealed a sarcoma, which was positive for Smooth Muscle Actin and negative for S100 on cell block immuno-histochemistry (IHC). The past history revealed surgical resection of a retroperitoneal mass in 2010 which was diagnosed on histopathology and IHC as leiomyosarcoma. A final diagnosis of metastatic deposits from leiomyosarcoma was made. Retroperitoneal leiomyosarcoma presenting as scalp and subcutaneous metastasis is an unusual presentation. Adequate clinical history and a high index of clinical suspicion is required to detect cutaneous and subcutaneous metastatic deposits occurring five years after surgical resection.