Unicentric Castleman's Disease as a Localized Retroperitoneal Mass: A Case Report and Review of Literature.

Castleman's disease (CD) is a rare disorder characterized by proliferation of the lymphoid tissue. Clinically, it presents in two forms either a unicentric (UC) or multicentric. Mediastinum is the most common location. UC retroperitoneal presentation is rare. We report a case of 29-year-old female who presented with left loin pain, and on abdominal imaging, evaluation identified a retroperitoneal mass in the left hypochondrium in the pararenal space. Mass was surgically excised entirely. Histopathological examination demonstrated hyaline vascular type of CD. CD should be considered in differential diagnosis of retroperitoneal mass, especially in equivocal cases. We also reviewed literature of 134 cases of retroperitoneal CD to analyze the presentation, management, and outcome.