Desmoplastic Small Round Cell Tumor of the Ovary: A Case Report With Atypical Morphologic Features and Literature Review.

Desmoplastic small round cell tumor (DSRCT), an aggressive malignancy classically seen in adolescents and young adults with a strong male predominance, is exceptionally rare in the ovary. We report a 33-year-old woman with ovarian DSRCT presenting as a pelvic mass and peritoneal metastases. Histopathology revealed small round cell nests within desmoplastic stroma, exhibiting atypical architectural patterns (single-file, follicular-like cystic, microcystic, and solid). Immunohistochemistry demonstrated coexpression of epithelial (pan-keratin) and mesenchymal markers (vimentin, desmin), while molecular analysis confirmed the EWSR1::WT1 gene fusion. Despite multimodal therapy, the patient died 24 months after surgery. A review of 23 ovarian DSRCTs proposed a classification: ovarian-dominant and extraovarian-dominant subtypes. Ovarian-dominant patients showed significantly prolonged median survival (24 vs 10 months, P = .026), underscoring the prognostic relevance of anatomical classification. Ovarian DSRCT poses diagnostic challenges due to histomorphological mimicry of common malignancies. Although this subclassification may aid prognostication, multicenter validation is warranted.