A Case of Ovarian Primary Solid Pseudopapillary Neoplasm With Multiple Organ Metastases.

Solid pseudopapillary neoplasm (SPN) is a rare tumor usually arising in the pancreas, while primary ovarian SPN is extremely uncommon. We report a case of ovarian SPN with multi-organ involvement. A woman in her 40s presented with abnormal uterine bleeding and abdominal distension. Imaging revealed a large 20-cm left ovarian mass with liver and lung lesions, but no pancreatic tumor. She underwent total abdominal hysterectomy, bilateral salpingo-oophorectomy, and partial omentectomy. The ovarian tumor was well-circumscribed with hemorrhage and necrosis. Histologically, the tumor displayed a solid and pseudopapillary architecture with mild nuclear atypia and prominent vascular invasion. Immunohistochemistry demonstrated nuclear β-catenin and loss of E-cadherin. Genetic analysis confirmed a CTNNB1 exon 3 mutation, while FOXL2 and DICER1 mutations were absent. The findings supported the diagnosis of primary ovarian SPN. The disease progressed with bone and lung metastases despite adjuvant chemotherapy, resulting in the patient's death 16 mo after surgery. An autopsy was performed, and the absence of a pancreatic tumor was confirmed. This case underscores the diagnostic importance of recognizing ovarian SPN and its potential for aggressive behavior. Awareness of its morphologic, immunophenotypic, and molecular features is essential for distinction from other ovarian tumors.