Neuroendocrine cells in cystic mucinous tumours of the ovary.

This histogenesis of cystic mucinous ovarian tumours is still controversial. It has been proposed that these neoplasms may arise from metaplastic ovarian surface epithelium. Others have suggested that these tumours represent monophyletic (intestinal) types of teratoma. Against this background we have studied the presence of different types of neuroendocrine cells in a series of cystic mucinous ovarian tumours. Argyrophil neuroendocrine cells were found almost exclusively in tumours which were histologically classified as borderline or low-grade mucinous carcinomas, whereas these cells were very rare in mucinous cystadenomas and in grade III and IV carcinomas. Several gut peptide hormones could be demonstrated in these cells, but only in borderline tumours and low-grade mucinous carcinomas. Mucin histochemistry did not reveal characteristic patterns in these neoplasms. The results confirm that with regard to the presence of endocrine cells the epithelium of borderline mucinous cystadenomas and mucinous cystadenocarcinomas bears strong resemblance to intestinal epithelium. These findings do not rule out the possibility that these tumours arise by metaplasia from ovarian germinal epithelium but are equally compatible with a teratomatous origin. The epithelium of most benign mucinous cystadenomas resembles that of ovarian inclusion cysts.