Ovarian mucinous and mixed epithelial carcinomas of mullerian (endocervical-like) type: a clinicopathologic analysis of four cases of an uncommon variant associated with endometriosis.

The epithelial cells of ovarian mucinous carcinomas may sometimes appear similar to those of gastrointestinal or endocervical mucinous carcinomas, but most are composed of cells that do not suggest any particular derivation. We report four cases of mucinous ovarian carcinoma in which the cells were entirely or almost entirely endocervical-like. The patients' ages were 34, 43, 44, and 50 years. Two patients had bilateral tumors confined to the ovaries at initial staging; both also had synchronous endometrial carcinomas of the mucinous type. The two other patients had unilateral tumors, both with invasive metastases in the pelvis and abdomen at initial staging. In one of the latter cases a mullerian (endocervical-like) mucinous borderline tumor (MMBT) of the opposite ovary had been removed 5 years earlier, and in this case and two other cases the ovarian carcinomas had foci resembling MMBT, suggesting that they may be an invasive counterpart to these tumors. The six tumors ranged from 4 to 19 cm; five were grossly cystic with papillary or solid areas, and one was entirely solid. They were composed of closely packed glands, cysts, and cysts containing complex papillae. There was abundant intraglandular and intracystic mucin. The epithelial cells were well differentiated with infrequent mitoses and most were tall with mucinous cytoplasm resembling normal endocervical glandular cells. In three tumors there also were round to polygonal cells with eosinophilic cytoplasm; endometrioid foci were present in three tumors and a squamous focus was present in one. One tumor had a focally infiltrative growth pattern with a desmoplastic stromal reaction; the remaining five tumors had an exclusively confluent (expansile) pattern of invasion. Endometriosis was present in residual ovarian tissue adjacent to four tumors in three patients and had marked epithelial proliferation in three. All patients were treated postoperatively with chemotherapy and were without clinical recurrence with follow-up intervals of 8 months, 1.2 years, 2.9 years, and 3.8 years. By immunohistochemical analysis the neoplastic epithelium was positive for estrogen and progesterone receptor proteins, vimentin, and cytokeratin 7, and negative or only focally positive for carcinoembryonic antigen and cytokeratin 20, a profile that differs from that of the usual mucinous ovarian carcinoma and is supportive of a mullerian derivation. As with MMBTs, there was a strong association with endometriosis, and these tumors likely arise from endometriosis, possibly through an MMBT precursor in some cases. To better understand their clinicopathologic features and pathogenesis, this uncommon variant should be separated from the usual type in future studies of mucinous carcinomas of the ovary.