Retroperitoneal masses represent a diagnostic challenge in imaging due to their uncommon location and variable presentation. Schwannomas are one of the possible etiologies. We report the case of a 50-year-old woman who presented to a tertiary referral hospital in Bucaramanga, Colombia, with chronic abdominal pain. Physical examination was unremarkable, but imaging revealed a giant retroperitoneal mass confirmed on contrast-enhanced abdominal computed tomography. The lesion showed neoplastic features, displacing the inferior vena cava and right kidney. The patient underwent surgical resection with radical lymphatic dissection, and histopathology confirmed a benign schwannoma. This case emphasizes the importance of considering schwannoma in the differential diagnosis of retroperitoneal tumors and illustrates the correlation between imaging and histopathologic findings.