Surgical Improvement of Neuropathy-Induced Calf Muscle Hypertrophy and Creatine Kinase Elevation: A Case Report

Peripheral neuropathy and radiculopathy often result in skeletal muscle disorders, typically leading to muscle atrophy. Concurrent muscle hypertrophy or persistently elevated creatine kinase (CK) is rare. While muscle hypertrophy is commonly observed in myogenic diseases, such as muscular dystrophy, acromegaly, inflammatory myopathies, and hypothyroidism, reports of muscle hypertrophy caused by neuropathy are infrequent. We encountered a patient with persistently elevated CK levels and unilateral lower leg muscle hypertrophy associated with neuropathy. The patient had cauda equina syndrome symptoms and pain in the left lower leg. Lumbar spine magnetic resonance imaging (MRI) revealed central spinal stenosis, which was believed to be the cause of the symptoms. Lower-limb MRI revealed high signal intensity in the gastrocnemius muscle on fat-suppressed T2-weighted imaging. Surgical treatment improved the radiculopathy, hypertrophy, and pain in the left lower leg. During the one-year follow-up, improvement was confirmed with both MRI and nerve conduction studies. Calf muscle hypertrophy associated with neuropathy has been reported; however, no reports have demonstrated pre- and postoperative changes with MRI and nerve conduction studies. We report a patient with lower leg muscle hypertrophy and persistent CK elevation associated with neuropathy, along with a literature review.