Unusual ovarian stromal tumor with radiation changes mimicking carcinoma

Radiation-related changes including fibrosis, nuclear enlargement, hyperchromasia and cytoplasmic vacuolization may alter the appearance of normal ovarian tissue and ovarian tumors. We describe radiation-related changes in ovarian stromal neoplasm with mixed features of sclerosing stromal tumor and fibrothecoma. The right ovarian mass was discovered in a 38 year-old woman with past history of invasive squamous cell carcinoma of the cervix treated with cone biopsy and brachytherapy. The low power architecture of cellular pseudolobules and small sheets of tumor cells with scattered hyaline plaques was consisted with the pattern of combined sclerosing stromal tumor and fibrothecoma. However, the presence of severe cytologic atypia, as well as clear cell and signet ring differentiation and arrangements of tumor cells in single files and nests, raised a possibility of primary or metastatic carcinoma. The tumor cells were positive for calretinin, vimentin, inhibin, and WT1 and negative for AE1/3, cytokeratin 7 and 20, CD99, estrogen and progesterone receptors, mammaglobin, chromogranin, and S100 protein. Based on the results of immunostains and a subsequently provided history of radiation, a diagnosis of sex cord stromal tumor with mixed fibrothecoma and sclerosing stromal differentiation was made. Radiation-related atypia and fibrosis in sex cord stromal tumor may create a pattern mimicking carcinoma and therefore, in the presence of unusual histology, the use of immunohistochemistry is recommended.