Dedifferentiated Carcinoma of the Ovary: A Rare Aggressive Subtype

Dedifferentiated carcinoma of the ovary (DDOC) is a rare and aggressive malignancy characterized by both differentiated and undifferentiated carcinoma components. While its endometrial counterpart, dedifferentiated carcinoma of the endometrium, is more frequent, DDOC remains poorly understood. We present the case of a young woman who presented with acute abdominal pain and was found to have a large complex ovarian mass. Histopathological examination revealed a combination of endometrioid carcinoma and undifferentiated carcinoma. Immunohistochemical analysis demonstrated distinct staining patterns, with the undifferentiated component exhibiting focal pan-cytokeratin positivity and loss of paired box gene 8 and estrogen receptor expression. The patient underwent standard paclitaxel-carboplatin chemotherapy but experienced rapid disease progression. DDOC poses significant diagnostic challenges due to its histological overlap with other high-grade ovarian malignancies. The presence of an undifferentiated component imparts a poor prognosis, even when it constitutes a minor portion of the tumor. Improved recognition, molecular characterization, and exploration of targeted therapies are essential for better clinical management of this rare and aggressive entity.