Abstract
Uterine leiomyomas, benign tumors common in reproductive-aged women, can display rare variants such as hydropic leiomyoma (HL), which exhibit unique histological features like zonal edema and increased vascularity. However, due to its rarity, comprehensive clinical knowledge about HL is limited. We report a case of a 49-year-old Japanese woman who was premenopausal and nulliparous, presenting with a two-year history of abdominal distension. An MRI scan revealed a 20 cm mass in the posterior part of the uterus, exhibiting characteristics suggestive of an ovarian tumor. During laparotomy, a cystic tumor connected with a swollen fibroid was found, and pathology confirmed HL. This case emphasizes that hydropic leiomyomas can mimic malignant tumors on ultrasonography due to their atypical features, necessitating additional evaluations using alternative imaging techniques or histopathological examinations for accurate diagnosis and appropriate management. The patient recovered uneventfully, broadening our understanding of HL's clinical presentation.