Histological Origin and Clinicopathological Analysis of Primary Ovarian Neuroendocrine Neoplasms

Purpose To investigate the histological origin and clinical and pathological features of primary ovarian neuroendocrine neoplasms. Methods We retrospectively analyzed nine cases of ovarian neuroendocrine neoplasms diagnosed at our hospital from January 2009 to January 2021. Results The mean age of the nine patients was 44.9 ± 15.2 years (range, 28–68 years). Six cases manifested ovarian carcinoid cancer, and the pathological types were insular and trabecular carcinoid; microscopic observation showed that the carcinoid components were limited and that stromal reaction was slight. Four cases showed teratomas, with the carcinoid components not displaying adjacent mucinous glands; and the other cases exhibited carcinoid cancer as the only tumor component, without adjacent or migratory epithelial components. The six patients were followed up for 76.6 ± 41.2 (6–123) months after resection, without disease. Two cases manifested adenocarcinoma admixed with neuroendocrine carcinoma, and the intermigration of neuroendocrine carcinoma and adenocarcinoma components could be observed; and one case was an isolated small cell neuroendocrine carcinoma with no epithelial proximity or migration observed. Adenocarcinoma admixed with neuroendocrine carcinoma and small-cell neuroendocrine carcinoma exhibited an obviously promoted interstitial reaction and damaging infiltration: these three patients underwent radical surgery supplemented by postoperative radiotherapy and chemotherapy, and follow-up lasted 34.6 ± 24.2 (7–52) months; two patients died and one showed recurrence. Conclusions Ovarian neuroendocrine neoplasms may reflect multiple tissue origins, carcinoid and simple neuroendocrine neoplasms with no adjacent, transitional epithelium, and may originate from original/transformed neuroendocrine cells or stem cells of the ovarian stroma. In addition, the adenocarcinoma admixed with neuroendocrine carcinoma may originate from dedifferentiated epithelium. The prognosis with carcinoid cancer is favorable, while the prognosis for neuroendocrine carcinoma is poor.