Idiopathic multicentric Castleman disease in an HIV-positive child.

A preadolescent HIV-positive girl from Southern Africa presented to a public healthcare facility with fever and unilateral facial and neck swelling. Clinical examination revealed generalised lymphadenopathy, hepatosplenomegaly, hypertension and haematuria. A provisional diagnosis of poststreptococcal glomerulonephritis was made; however, when the patient displayed no clinical improvement on supportive treatment, she was referred to a tertiary hospital for further evaluation. The peripheral blood smear showed marked agglutination, which improved on warming. Serum protein electrophoresis demonstrated a monoclonal protein, yet the bone marrow plasmacytosis of 30% was polyclonal and human herpesvirus 8 negative. Subsequently, a lymph node biopsy confirmed a diagnosis of plasmacytic idiopathic multicentric Castleman disease. The atypical presentation contributed to delayed diagnosis and prompted unnecessary invasive investigations in a paediatric patient.