A Case Report of Malignant Struma Ovarii With Papillary Thyroid Carcinoma.

Struma ovarii is a monodermal variant of mature teratoma, primarily composed of thyroid tissue. It is a rare ovarian tumor with nonspecific clinical and imaging features. While most cases are benign, a small proportion can undergo malignant transformation, most commonly to papillary carcinoma. Due to its rarity, diagnostic criteria and management guidelines remain poorly defined. A young adult female presented with abdominal pain in our hospital. Imaging studies including ultrasonography and CT scan revealed a midline complex cystosolid mass. The patient underwent right-sided cystectomy and salpingo-oophorectomy. Histopathological and immunohistochemical analysis confirmed the diagnosis of malignant struma ovarii. Malignant transformation in struma ovarii is uncommon and follows the same diagnostic criteria as thyroid malignancies. Clinical presentation and imaging features are often nonspecific, and diagnosis relies on histopathology and immunohistochemistry. Surgical resection is the preferred treatment, with the extent determined by tumor characteristics and patient factors. Malignant struma ovarii is a rare ovarian tumor requiring careful histopathological evaluation for diagnosis. Awareness of this entity is crucial for guiding appropriate management.