Lenalidomide-Associated Rhabdomyolysis Progressing to Bilateral Compartment Syndrome and Permanent Foot Drop.

Lenalidomide is widely used for the treatment and maintenance of multiple myeloma and is generally considered to have a favorable safety profile. However, severe skeletal muscle toxicity associated with lenalidomide has been rarely reported. We describe a 52-year-old man with multiple myeloma who developed acute bilateral lower-extremity pain, cramping, weakness, and paresthesia while receiving lenalidomide therapy. Laboratory evaluation revealed marked rhabdomyolysis, and imaging and clinical findings were consistent with bilateral lower-leg compartment syndrome. Despite emergent bilateral fasciotomies resulting in resolution of pain and normalization of creatine kinase levels, the patient developed persistent bilateral foot drop with residual sensory deficits. To our knowledge, this represents the first reported case of lenalidomide-associated rhabdomyolysis progressing to bilateral compartment syndrome with permanent neurologic sequelae. This case underscores the importance of early recognition of muscle toxicity, prompt laboratory evaluation, and timely surgical intervention to mitigate irreversible functional impairment.