Small-cell (oat cell) carcinoma of the endometrium.

: We report a case of small-cell (oat cell) carcinoma of the endometrium in a 59-year-old woman. The tumor was confined to a portion of an adenomatous polyp. It exhibited argyrophilia with Grimelius' stain and dense-core endocrine-type granules by electron microscopy. The patient was alive and well one year later. To our knowledge, this is the fourth reported case of a small-cell carcinoma of the endometrium exhibiting endocrine differentiation.