Case Presentation: A 30-year-old male with type two diabetes mellitus and morbid obesity presented with one month of generalized weakness, fatigue and fever. This was his third hospitalization with these same symptoms; no definitive diagnosis was identified the previous two. He also complained of headache, a dry cough, and upper abdominal pain. Pertinent exam findings included abdominal tenderness to palpation in the upper quadrants with pain radiating to the back, without palpable organomegaly or lymphadenopathy. Chest x-ray, blood and urine cultures were negative. ESR and CRP were elevated at 123 and 28 respectively. CBC revealed a normal WBC count and normocytic anemia. CSF studies were pertinent for a mildly elevated WBC count. He was treated for aseptic meningitis thought to be secondary to NSAID usage. Of note, HIV and HHV-8 serum testing were negative and IL-6 was elevated. When daily fevers persisted, CT imaging was performed and showed splenomegaly and multiple enlarged lymph nodes. PET CT imaging revealed diffuse uptake within the spleen and lymph nodes. FNA biopsies of periaortic lymph nodes were unremarkable. Lymph node excisional biopsy was consistent with a diagnosis of multicentric Castleman’s disease. He was treated with rituximab weekly for four weeks as well as a prednisone taper. He subsequently had resolution of his fevers and normalization of his inflammatory markers and IL-6 levels. He later underwent radiation therapy to the abdominal region.
Discussion: Castleman’s disease is a poorly understood lymphoproliferative disorder associated with hypercytokinemia usually in the setting of HIV and/or HHV-8. While unicentric Castleman’s disease is uncommon, the multicentric variant is extraordinarily rare. Further, multicentric Castleman’s disease with negative HIV and HHV-8 serologies though elevated IL-6, termed idiopathic MCD, has been gaining attention in the literature; it’s etiology and pathophysiology remain unclear, namely the source of the hypercytokinemia that is observed. This case also highlights a diagnostic dilemma in a case of fever of unknown origin; particularly as his initial FNA was non-diagnostic and persistence with surgical lymph node biopsy was required to make his eventual diagnosis.
Conclusions: This case demonstrates a very rare case of HHV-8 and HIV negative idiopathic multicentric Castleman’s disease. This type of Castleman’s disease, referred to as idiopathic multicentric Castleman’s is only recently being more clearly elucidated. However, its pathophysiology and treatment options remain poorly understood.