Monoclonal Gammopathy of Neurological Significance in a Patient With Chronic Lymphocytic Inflammation With Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS Syndrome): A Case Report of a Rare Entity

Paraproteinemias or monoclonal gammopathies constitute a broad spectrum of heterogeneous clonal disorders of plasma cells characterized by the secretion of monoclonal proteins of heavy or light chains and the development of symptoms associated with them through mechanisms independent of tumor burden. Specifically, peripheral neuropathies represent an increasingly recognized manifestation of these paraproteinemias. We report a case of a 71-year-old female who presented to the emergency department with clinical symptoms of perioral paresthesias associated with an ataxic gait that progressively compromised her functionality, eventually completely limiting her ability to walk. Initially diagnosed with chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS syndrome), management with corticosteroids was initiated, leading to partial improvement. After comprehensive etiological studies ruled out common causes of peripheral neuropathy (PN), a monoclonal peak of immunoglobulin M (IgM) was detected. With the initiation of appropriate treatment, the patient progressively regained her ability to walk. Unfortunately, due to prolonged corticosteroid use, she developed osteoporosis and multiple fragility fractures, which again limited her mobility. CLIPPERS syndrome coexisting with monoclonal gammopathy is extremely rare, highlighting the importance of this report.