Primitive neuroectodermal tumor of the uterus: a case report and review of literature.

A case of primitive neuroectodermal tumor arising in the uterine corpus of a 43-year-old woman is presented. The tumor mass was 13.3 cm and extended to the uterine serosa, endocervical stroma, and left adnexa. Histologically, the tumor was composed of small blue cells with scant cytoplasm, indistinct cell borders, hyperchromatic round nuclei, and inconspicuous nucleoli focally forming pseudorosettes, suggestive of neuroectodermal origin. The tumor cells displayed strong immunoreactivity for CD99 and FLI1. Cytogenetic fluorescence in situ hybridization study revealed presence of an EWS-FLI1 fusion gene. To the best of our knowledge, this is the first case of primitive neuroectodermal tumor of the uterus with diagnosis confirmed by FLI1 immunohistochemical labeling and demonstration of t (11; 22) by fluorescence in situ hybridization.