Introduction: Brenner tumors are rare transitional cell tumors of the ovary. They are usually benign neoplasms, of solid or solid-cystic structure and small size. We describe the case of a benign, predominantly cystic Brenner tumor measuring 39 cm in diameter.
Case report: A 62-year-old woman presented to the outpatient visit complaining about vague abdominal symptoms such as constipation and meteorism. Ultrasonography and CT scan showed the presence of a voluminous cystic mass, with fluid content, displacing other intra-abdominal organs. The patient underwent elective surgical excision, and there were no complications. Definitive pathological examination showed a metaplastic benign Brenner tumor.
Conclusion: The largest benign Brenner tumors reported in literature have been up to 30 cm in size, and greater size has been thought to be a predictor of malignancy. We have seen, however, that it is possible for larger lesions of this type to have a completely benign behavior; consequently, a benign nature should not be excluded even in the event of a large ovarian lesion.