We report four cases of uterine
tumors with neuroectodermal differentiation. One
tumor had neuroectodermal component only; in the three other
tumors, the neuroectodermal component was admixed with another component, namely
rhabdomyosarcoma (1 case), and
endometrioid adenocarcinoma (2 cases). Histologically, the neuroectodermal component consisted of small to medium sized cells arranged in diffuse sheets. The
tumor cells had round nuclei with stippled to coarsely granular
chromatin, mostly with non-prominent nucleoli, and scant eosinophilic or amphophilic cytoplasm. Immunohistochemically, 4/4
tumors showed expression of
vimentin,
synaptophysin and CD56; 3/4
tumors were CD99 and NSE positive; 2/4
tumors showed focal expression of
S-100 protein; and 1/4
tumors had focal dot-like cytoplasmic positivity for
cytokeratin AE1/AE3. FLI-1 was negative in all cases. FISH examination was performed and none of the
tumors showed rearrangement of EWSR1 gene. Uterine
tumors with neuroectodermal differentiation are rare; to the best of our knowledge only 44 cases have been reported in the literature to date, referred to as
Ewing sarcoma, peripheral
PNET (pPNET),
PNET (not otherwise specified) and uterine
tumors with neuroendocrine differentiation.