Intestinal-type mucinous ovarian carcinoma arising from a seromucinous precursor lesion.

OBJECTIVE: Mucinous ovarian carcinoma is a tumor with gastrointestinal differentiation, which is not associated with endometrial-type (endometriotic or seromucinous) precursors. Here, we describe a peculiar case of mucinous ovarian tumor with intestinal differentiation arising in a seromucinous lesion, which may represent a distinct entity. CASE PRESENTATION: A 58-year woman underwent surgery due to a 14.5-cm ovarian mass with lymph nodal, peritoneal, omental and colorectal involvement. Histological examination with ancillary immunohistochemical analysis has been performed. Histologically, the mass was a carcinoma with intestinal differentiation and expansile growth pattern, arising in a seromucinous cystadenoma with intestinal metaplasia. Both the carcinoma and the metaplasia showed loss of Müllerian markers (estrogen and progesterone receptors, PAX8) and positivity for intestinal-type markers (cytokeratin 20, CDX2). CONCLUSIONS: Our case may represent the ovarian counterpart of endometrial gastrointestinal-type carcinoma, which is an aggressive entity developing from gastrointestinal metaplasia of the endometrial epithelium. Acknowledging the existence of such entity might be relevant in terms of diagnosis and patient management.

When a mimicker wears strange faces: description of an osteogenic melanoma arising within an ovarian teratoma with focus on its late peritoneal relapse.

Secondary malignancies arising within mature teratomas are a rare event, originating from malignant transformation of the tissues derived from one of the three germ cell layers. Osteogenic melanoma is exceedingly rare histologic variant of malignant melanoma, in which the melanoma is associated to an osteogenic sarcoma component. To the best of our knowledge, first case of osteogenic melanoma arising within mature ovarian teratoma in a 30-year-old woman without evidence of a primary cutaneous or visceral melanoma. The present case showed an unusual morphological and immunohistochemical pattern and was incorrectly diagnosed as undifferentiated carcinoma. After a 15 years follow-up period, the patient presented a peritoneal recurrence histologically constituted by epithelioid cells with prominent osteoid formation and with immunohistochemical expression of melanocytic markers (S100, HMB-45). Heterozygote Mutation V600E/E complex has been detected in the BRAF exon 15 sequence. The case was then interpreted as osteogenic melanoma. The present case contributes to widen the spectrum of neoplasms derived from malignant transformation of ovarian teratomas and provides also new insights about the clinical behavior of osteogenic melanoma when arising outside its usual anatomical location.