A case of Castleman's disease that presented as a retroperitoneal mass.

BACKGROUND: A 35-year -old man presented to a local emergency room with acute left-flank pain and a medical history of nephrolithiasis. There were no aggravating or relieving factors for the left-flank pain and no other presenting symptoms, and the physical examination was unremarkable. INVESTIGATIONS: Complete blood count, urinalysis, serum tumor markers, scrotal ultrasonography, CT scan of the abdomen (with and without contrast), MRI of the abdomen. DIAGNOSIS: Unicentric Castleman's disease (hyaline-vascular type). MANAGEMENT: Surgical exploration and excision. Pathologic and immunohistochemical work-up confirmed the diagnosis. CT scan after 7 months was normal with no evidence of recurrence.