ABSTRACT: Retroperitoneal schwannomas are rare benign tumors originating from Schwann cells and are seldom diagnosed preoperatively due to their anatomical location and nonspecific clinical-radiological features. We report a case of 25-year-old woman with progressive right upper abdominal pain for eight months and a palpable right subcostal mass. Imaging showed a large, well-circumscribed, heterogeneously enhancing retroperitoneal lesion displacing right kidney with secondary hydronephrosis. With a provisional diagnosis of ganglioneuroma, laparoscopic complete excision was performed with repair of iatrogenic renal vein rents. Histopathology confirmed benign schwannoma with Antoni A and B areas. Recovery was uneventful, with no recurrence at six months follow-up period.

Impact statement: Current case highlights the diagnostic challenge of retroperitoneal schwannoma, while illustrating the feasibility of laparoscopic complete excision for large lesions with favorable postoperative and short-term oncological outcomes.

Key words: Antoni; hydronephrosis; retroperitoneal; schwannoma; Verocay.