Chondrosarcomatous differentiation in metastatic deposit of serous papillary cystadenocarcinoma.

A rare case of serous papillary cystadenocarcinoma of the ovary showing chondrosarcomatous differentiation in a metastatic deposit late in the clinical course is reported. A 49-year-old female underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy for bilateral ovarian tumors. Histological diagnosis was serous papillary cystadenocarcinoma of both ovaries with lymph node metastasis. After six courses of chemotherapy, she was confirmed to be in complete remission following a second laparotomy. Following additional chemotherapy, a third laparotomy disclosed swollen left inguinal lymph nodes. In one of these nodes, approximately 5.0 cm in greatest diameter, the predominant histological features were: chondrosarcoma of the bone and soft tissue, with small foci of serous papillary adenocarcinoma and squamous epithelium. A histological transition between mesenchymal and epithelial areas was identified. Immunohistochemical positivity for broad-spectrum cytokeratin (AE1/AE3), vimentin, epithelial membrane antigen, and S-100 protein was observed in both chondrosarcomatous and epithelial areas. The current evidence may suggest that the chondrosarcomatous differentiation was derived from the metastatic epithelial component.