Unicentric Castleman's Disease with an Unusual Clinical Behavior

Castleman's disease is a rare clinicopathological condition characterized by hyperplasia of lymph nodes. We report the case of a 12-year-old boy who presented with painful oral and genital ulcers, who was assumed to have Behçet's disease. However, the patient did not show any clinical improvement on colchicine and systemic corticosteroids. Later, the patient developed severe abdominal pain and vomiting. Abdominal CT revealed a mass lesion superior to the right kidney. After a thorough investigation, he was diagnosed with unicentric Castleman's disease. Despite the complete resection of the mass, the patient continued to have the symptoms of abdominal pain and orogenital ulcers. Immunomodulatory therapy resulted in remarkable clinical improvement. This case report demonstrates how unicentric Castleman's disease can share similar clinical behavior to the multicentric disease.