Clinical spectrum of POEMS-associated multicentric Castleman disease with renal involvement: a diagnostic challenge

Castleman disease (CD) is a rare and heterogeneous lymphoproliferative disorder with a wide variety of clinical presentations and outcomes. Human herpesvirus-8 (HHV-8) related CD corresponds to the most common subtype of the multicentric Castleman disease (MCD). However, if HHV-8 is negative, POEMS (peripheral neuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) associated with MCD or idiopathic MCD are the cause in a subgroup of patients. Considering the rarity of POEMS and MCD association, we herein describe a patient with a typical presentation based on clinical, laboratory and tissue biopsy data. We report a diabetic patient who presented with asthenia, edema, skin lesions manifested by scarring in chiropodactyls, multiple lymph node enlargement in the neck, armpits and inguinal areas, splenomegaly, severe anemia, thrombocytopenia, and mixed polyneuropathy. Hematuria and proteinuria were detected. The patient developed progressive renal failure requiring dialysis. Renal biopsy showed mesangial expansion with mesangial hypercellularity, and lymphoplasmacytoid cells focally distributed in tubules and interstitium, which were compatible with acute tubulointerstitial nephritis. In immunofluorescence, no deposits of IgG, IgA, IgM, C1q, C3 or fibrinogen were found, and kappa and lambda were also negative. Lymph node biopsy revealed lymphoid tissue with follicular hyperplasia, sinusoidal and medullary infiltration of plasma cells. Immunohistochemistry confirmed positivity for B lymphocytes, T lymphocytes, and plasma cells in sub-capsular and para-follicular areas. The patient was diagnosed as POEMS-associated MCD variant, and chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone was started. The patient did not recover renal function and remained dialysis-dependent. To date, the renal involvement in MCD and POEMS syndrome seems to be uncommon as reported in few case series. Its pathophysiology is not well understood. In the spectrum of MCD, decreased renal function may have impact in patient survival. Early diagnosis and treatment are needed to control the systemic manifestations, and most importantly to avoid chronic organ damage