Abstract

Carcinoid tumors are low-grade, well differentiated and slow-growing neuroendocrine neoplasms. Primary carcinoid tumors of the ovary are extremely rare, accounting for less than 5% of all carcinoid tumors and less than 0.1% of all ovarian malignancies. They represent the second most frequent type of monodermal teratoma and may occur in pure form (15%) or combined with other teratomatous elements (85%). Primary ovarian carcinoids are more common than metastatic ovarian carcinoids, which are mostly of gastrointestinal origin. The distinction between ovarian primary and metastatic carcinoid is crucial and has various clinical, therapeutic and prognostic implications. To date, there are no specific histopathological or immunohistochemical criteria for differentiating between primary ovarian carcinoids and metastatic tumors from the gastrointestinal tract. However, features like the association with ovarian teratoma, unilaterality and the absence of lymphovascular invasion are considered to be suggestive of a primary ovarian carcinoid, rather than a metastatic tumor. Some studies suggest that CDX-2 may be a useful marker to distinguish primary ovarian carcinoids from metastatic ovarian carcinoids of gastrointestinal origin, but there are multiple reports demonstrating that insular and mucinous carcinoids of either origin may express this marker with various intensity. The current consensus is that in the absence of other teratomatous elements, it may be difficult or even impossible to determine whether an ovarian carcinoid is primary or metastatic. Much more relevant to the diagnosis seems to be the interpretation of ancillary immunohistochemical tests, in each individual clinical context. The case presented in this paper attempts to explore the most important diagnostic and therapeutic challenges posed by primary ovarian carcinoid tumors.