Ovarian mucinous cystadenoma with murale nodule of poorly differentiated squamous cell carcinoma. Report of a case

Abstract

Background. Mural nodules associated with mucinous and serous tumors of the ovary may represent a reactive process, a benign tumor, or a malignant neoplasm. Thus, the prognosis of the ovarian tumor can be dramatically modified by the presence of this nodule. We report the clinicopathologic and immunohistochemical findings of a case of a mural nodule of anaplastic squamous cell carcinoma associated with ovarian mucinous cystic tumor. Case report. The patient was a 66-year-old postmenopausal woman (gravida 1, para 1) with a 6-month history of increasing abdominal fullness. An abdominal ultrasound revealed a multilocular left ovarian cyst with a solid component. After total abdominal hysterectomy and bilateral salpingo-oophorectomy, the diagnosis of a mucinous cystadenoma with a focus of FIGO stage IC anaplastic carcinoma in the left ovary was made. The patient received six courses of chemotherapy; 3 months after completing chemotherapy, she developed rectosygmoidal wall metastases. Despite rectosygmoid resection and additional chemotherapy and radiotherapy, the disease persisted in the pelvis and the patient died 14 months after initial operation. The primary tumor nodule as well as metastatic rectosygmoid tumors were studied by conventional and immunohistochemical methods. Results. The left ovarian tumor measured 8.5 x 8 x 6 cm. On cut sectioning, it was multilocular with a solid 4.5 x 4 x 3 cm mural nodule. Microscopically, the cyst wall was predominantly lined with benign mucinous epithelium, with rare foci of endometriosis found in smaller locules. The solid area of the mural nodule showed nests of spindle or polygonal highly malignant cells with admixed inflammatory cells. Necrosis and hemorrhage were also present. The ovarian capsule was invaded by the pleomorphic tumor cells. In favor of a diagnosis of anaplastic carcinoma were poor circumscription of the nodule with lymph-vascular involvement and absence of a prominent inflammatory reaction with multinucleated giant cells of the epulis type. In addition, the metastatic rectosygmoid tumor showed poorly differentiated squamous cell carcinomatous features. Immunohistochemically, the atypical cells of the nodule as well as a metastatic tumor were uniformly positive for epithelial markers such as pan-cytokeratin, high-molecular weight cytokeratin, cytokeratin 7 and epithelial membrane antigen, negative for carcinoembryonic antigen and focally weakly positive for vimentin. Many of these cells were also immunoreactive for p53 (80-90%) and Ki-67 (40-50%). Conclusion. The occurrence of ovarian mucinous cystic tumor with mural nodule of poorly differentiated squamous cell carcinoma is evidently very uncommon, because we have not found a similar case in the literature. The malignant nodules composed of sarcoma or anaplastic carcinoma such as in our case are associated with an unfavourable outcome and must be distinguished from other sarcoma-like nodules that may also occur in the wall of mucinous ovarian tumours. Therefore, the implementation of strict morphologic criteria supplemented by immunohistochemistry aids in the sometimes difficult differential diagnosis among these types of mural nodules.