Neuroendocrine differentiation in Müllerian neoplasms: an immunohistochemical study of a pure endometrial small-cell carcinoma and a mixed Müllerian tumor containing small-cell carcinoma

Two neoplasms of the endometrium exhibiting histologic features of small cell carcinoma (SCC) were studied immunohistochemically for the presence of antigens indicative of neuroendocrine differentiation. The first case, a pure SCC, was positive for neuron-specific enolase (NSE), Leu-7, and chromogranin. The second case, a mixed müllerian tumor, had an extensive SCC component; the latter element was reactive for NSE and Leu-7. The first patient has had an unexpectedly long survival, while the second patient died with multiple distant metastases, containing only SCC.