Abstract

Cutaneous leiomyosarcoma is a rare malignant smooth muscle tumor that arises either superficially within the dermis or deep in soft tissues. Histologically these tumors demonstrate a dermal proliferation of elongated spindle-shaped cells arranged in interweaving fascicles with blunt-ended, cigar-shaped nuclei and eosinophilic cytoplasm. There is spectrum of pathological findings is broad with varying degrees of differentiation, nuclear atypia, and mitoses. Dermal leiomyosarcomas generally follow an indolent course with a relative tendency for local recurrence and low risk of distant metastasis. Unlike the dermal variant of leiomyosarcoma, subcutaneous leiomyosarcomas have a higher rate of locoregional recurrence and potential for distant metastasis. Cutaneous metastasis of leiomyosarcoma is an extremely rare occurrence with few cases reported in the literature. Metastasis to the skin can occur in the setting of a primary visceral leiomyosarcoma or primary cutaneous leiomyosarcoma. Herein we report two cases of metastatic leiomyosarcoma to the skin, one from gastric origin and the other from subcutaneous soft tissue. The scalp was the site of cutaneous metastasis in both cases. The development of cutaneous metastases appears to be a poor prognostic factor for leiomyosarcoma. Recognition of the metastatic potential of leiomyosarcoma to the skin, albeit rare, is important in further understanding the pathogenicity of this tumor.

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