Giant Recurrent Retroperitoneal and Ischioanal Lymphangioma in an Adult: A Case Report.

Background and Clinical Significance: Lymphatic malformations (cystic lymphangiomas) are rare benign tumors in adults, with retroperitoneal and ischioanal involvement being exceptionally uncommon. These lesions often present significant surgical challenges because of their infiltrative growth pattern and high risk of recurrence following incomplete excision. We present a rare case of a giant recurrent retroperitoneal lymphangioma with extension into the pelvic and perineal regions after two previous unsuccessful surgical interventions; Case Presentation: A 46-year-old Hispanic female presented with progressive pelvic and perineal swelling associated with discomfort and functional limitation. The patient had a history of two prior surgeries for lymphangioma recurrence. Imaging studies revealed a large multicystic retroperitoneal mass extending through the pelvis into the ischioanal fossa and perineal region. Given the lesion's size and complex anatomical involvement, a multidisciplinary surgical approach was planned. The patient underwent a combined abdominal-perineal en bloc resection, achieving complete removal of a 20 × 8 × 9.5 cm mass while preserving anal sphincter integrity and function. Histopathological examination confirmed the diagnosis of cystic lymphangioma. The postoperative course was uneventful, and no recurrence was observed for 6 months follow-up; Conclusions: Giant recurrent pelvic lymphangiomas require complete en bloc excision and a multidisciplinary approach to ensure disease clearance and prevent recurrence.