Mixed Cryoglobulinemia Syndrome Associated with Non-HCV B-Cell Lymphoproliferative Disorder Presenting with Gangrene and Peripheral Neuropathy.

Mixed cryoglobulinemia is a rare disorder characterized by gangrene, weakness, and arthralgias with variable organ involvement. It is often associated with hepatitis C, HIV, and immunological disorders. Diagnosis is based on clinical features and laboratory testing with serology detecting cryoglobulins. Our patient, a 64-year-old female, presented with weakness, fatigue, and discoloration of her fingers and toes. Physical examination showed upper- and lower-extremity skin changes with dry gangrene. Serology showed a non-hepatitis C status, positive cryoglobulin test with a positive rheumatoid factor, and monoclonal IgM-kappa, confirming the diagnosis of mixed cryoglobulinemia. She was treated with intravenous immunoglobulins, glucocorticoids, multiple cycles of rituximab, cyclophosphamide, and plasma exchange. Following a significant event of exacerbation and relapse requiring a below-knee amputation, this case report aims to raise awareness among clinicians to consider this as a rare cause of gangrene and peripheral neuropathy in an elderly adult.