Unicentric retroperitoneal Castleman's disease in young Nepalese women

Castleman disease (CD) is a rare lymphoproliferative disorder of uncertain etiology, most commonly affecting the chest and neck, with retroperitoneal involvement being exceptionally rare. It can present as either unicentric or multicentric disease, with the unicentric form typically affecting younger individuals. Due to its rarity and overlapping features with conditions like non-Hodgkin lymphoma and paraganglioma. CD is often misdiagnosed, making immunohistochemical analysis crucial for accurate diagnosis. We report a rare case of retroperitoneal CD in a 23-year-old female referred to our hospital after a CT scan revealed a retroperitoneal tumor anterior to the lower pole of her left kidney at the L3-L4 vertebral level. An initial core biopsy suggested paraganglioma; however, following laparoscopic tumorectomy, histopathological analysis confirmed Castleman disease of the hyaline vascular and plasma cell type.