Epithelioid leiomyosarcoma with rhabdoid features.

Leiomyosarcomas (LMS) are the most common type of uterine sarcoma. Most LMS have typical histologic features, and variants such as epithelioid LMS, myxoid LMS, LMS with osteoclast-like giant cells and LMS with rhabdoid features occur only rarely. Rhabdoid cells were first described in rhabdoid tumor, a distinctive renal neoplasm of infancy. Such tumors are composed of diffuse proliferation of rhabdoid cells that are round or polygonal in shape with eccentric nuclei, prominent nucleoli and glassy eosinophilic cytoplasm containing hyaline-like inclusion bodies. In the literature, extrarenal localizations of malign rhabdoid tumors have been described in a variety of primary sites such as the central nervous system, liver, skin and soft tissues. These characteristic rhabdoid cells have been reported in sarcomas and carcinomas of various types and in a few cases of uterine sarcomas. The presence of rhabdoid cells in tumors is considered to be a predictor of aggressive tumor behavior. Our case is that of a 56-year-old woman who was admitted to the state hospital with left inguinal mass. Microscopically the tumor was admixed of three different types of cell with spindle, epithelioid or rhabdoid features. Immunopositive cytoplasmic staining for myoglobulin and desmin was seen in rhabdoid cells, and cytokeratin immunopositivity was observed in epithelioid and some rhabdoid cells. Epithelioid cells and spindle cells were also SMA positive. The histopathologic and immunohistochemical findings support the diagnosis of epithelioid LMS with rhabdoid features. We report this very uncommon LMS variant; to the best of our knowledge there are only a few cases in the English literature.