Breast metastasis from uterine leiomyosarcoma diagnosed by fine needle aspiration: a case report

Leiomyosarcomas of the breast are a rare subgroup of primary breast sarcomas. Even more rare is breast metastasis of an extramammary leiomyosarcoma. To date, only 4 cases have been reported in the literature.

We report a case of breast metastatic leiomyosarcoma in a 58-year-old woman with a prior history of uterine leiomyosarcoma, resected 18 months earlier. The breast mass was palpable and a fine needle aspiration (FNA) was performed. The microscopic examination showed cellular smears composed of loosely structured clusters and tissue fragments of spindle-shaped and polygonal or rounded malignant cells in disorderly arrangement. The tumor cells were medium- or large-sized, with basophilic cytoplasm and enlarged, irregular, hyperchromatic nuclei with nucleoli. Tumor giant cells and multinucleation were also present. The morphologic features along with immunocytochemical positivity for desmin, muscle-specific actin and vimentin indicated the diagnosis of a metastatic leiomyosarcoma.

FNA cytology can be a reliable method for the diagnosis of leiomyosarcoma. The morphologic criteria in combination Swith the clinical history and the immunocytochemical findings can indicate a definitive diagnosis and avoid additional painful and time-consuming diagnostic procedures for the appropriate patient's further clinical management.