Primary rhabdoid tumor of the ovary: When large cells become small cells

•The third case of pure primary malignant rhabdoid tumor of the ovary (MRTO) is described•SMARCA4 and SMARCB1 genetic analysis and immunohistochemistry are necessary for correct diagnosis of MRTO•MRTO and small cell carcinoma of the ovary, hypercalcemic type are essentially the same and should be treated as such.