Rapidly progressive glomerulonephritis in a patient with angioimmunoblastic T-cell lymphoma: a rare autopsy case showing IgA vasculitis and cylinder-like deposits.

Angioimmunoblastic T-cell lymphoma (AITL), a hematological malignancy, originates from follicular helper T cells. The primary site of AITL is the lymph nodes, but extranodal presentation is frequent in patients with advanced stages. Here, we report a rare case of a patient with AITL presenting with rapidly progressive glomerulonephritis (RPGN). The patient underwent computed tomography, which showed systemic lymph node swelling. RPGN was noted at the time of admission. Livedo was observed in the lower limbs with purpura on the foot. The patient was diagnosed with AITL based on lymph node biopsy. Skin biopsy revealed vasculitis with immunoglobulin A (IgA) deposits. Renal biopsy revealed endocapillary proliferative glomerulonephritis with massive subendothelial deposits and intraluminal thrombi. Immunofluorescence showed IgA, IgG, and complement component 3c-predominant granular staining pattern in the capillary and mesangial areas. Electron micrographs demonstrated dense cylindrical-like deposits in the subendothelial space. Chemotherapy drugs were administered, but the patient's respiratory distress increased until death. Upon autopsy, membranoproliferative glomerulonephritis and extensive necrotizing cellular crescent formation were observed in the glomeruli. Taken together, this case is a rare combination of AITL and RPGN showing both cylinder-like deposits suggestive of cryoglobulinemic glomerulonephritis (CN) and IgA vasculitis.