Unraveling the enigma: FATWO and its clinicopathologic implications.

Female Adnexal Tumour of probable Wolffian Origin (FATWO) is a rare gynaecological neoplasm of low malignant potential believed to originate from mesonephric remnants. Its rarity, non-specific presentation, histological heterogeneity and ill-defined radiological features make diagnosing them challenging.A female in her 60s presented with history of lower abdominal pain for 2 years. Her gynaecological history was unremarkable, with smooth menopausal transition. Pelvic examination revealed a firm, solid mass in the right adnexa. Imaging was suggestive of a right adnexal mass measuring 6×9×7 cm. She underwent staging laparotomy thereafter. Intraoperatively, an 8×8 cm solid, fibrous mass was noted. Histopathology and immunohistochemistry showed tumour cells with focal gyriform pattern positive for calretinin and WT-1 (Wilms Tumour -1) leading to a diagnosis of FATWO. She was kept on regular follow-up and no manifestations of recurrence were noted. Five years later, she is doing well.