Abstract

Mature cystic teratoma (MCT) is one of the most common benign ovarian tumors, but 1-2% of MCTs are transformed to a malignant neoplasm. Urothelial carcinoma (UC) or transitional cell carcinoma is the most common cancer in the urinary tract. However, UC is a very rare component of transformed malignancy of MCT. Here we report a case of UC arising in an MCT in a 52-year-old woman. Grossly, the ovary was partly cystic and partly solid. Microscopically, the cyst revealed the classic features of MCT and the solid area was papillary UC. By immunohistochemistry using cytokeratins and thrombomodulin, the UC showed a similar expression to that of UC arising in the urinary tract, rather than resembling a primary transitional cell carcinoma of the ovary. When UC is found in a component of MCT, the origin of the carcinoma should be evaluated and urinary tract examinations are required to rule out metastasis.

• Keywords: Ovarian neoplasms;Teratoma;Carcinoma, transitional cell