Castleman disease (CD) is a benign lymphoproliferative disorder that may present as a localized or multicentric form (see these terms). The clinical manifestations are heterogeneous, ranging from asymptomatic discrete lymphadenopathy to recurrent episodes of diffuse lymphadenopathy with severe systemic symptoms.

Severely increased amount of excretion of protein in the urine, defined as 3.5 grams per day or more in adults and 40 mg per meter-squared body surface area per hour in children.