To report a case of benign monomelic amyotrophy of lower limb (BMALL), and to
explore the etiology, pathogenesis, clinical manifestations, auxiliary examination, diagnosis and prognosis of the
disease in accordance with the literature. Methods: The clinical data of this patient were analyzed
retrospectively. The related domestic and foreign literatures were retrieved and analyzed. Results: Four years
ago, the patient found muscle atrophy of his right lower limb with no obvious incentive, gastrocnemius involved
mainly. Muscle atrophy gradually progressed upward. Compared with muscle atrophy, muscle weakness was
relatively mild. There were no paresthesia, pyramidal signs and medullary damage. Physical examination showed
normal right leg muscle tension, muscle strength 5— grade, tendon reflexes (-), no fasciculation fibrillation,
pathological sign (-). Muscle MRI showed right lower extremity gastrocnemius, soleus muscle, anterior tibialis,
quadriceps and gluteus maximus have varying degrees of atrophy. EMG showed right lower extremity
neurogenic damage. Right quadriceps muscle biopsy showed neurogenic muscular atrophy. In previously
reported 95 cases of BMALL patients, more patients were male, all patients had no symptoms of muscle
weakness, and a small part had mild sensory abnormalities. Electromyograms of all patients showed neurogenic
damage, and muscle biopsy all showed neurogenic muscle atrophy. Most patients have a good prognosis after
several years of follow-up. Conclusion: BMALL is a relatively benign neuromuscular disease. The clinical
manifestations are unilateral lower limb atrophy, muscular atrophy and myasthenia gravis disproportionately. The
onset of symptoms is insidious and the progression is slow without affecting daily life. The etiology and
pathogenesis are not clear currently. The diagnosis depends mainly on medical history, physical examination,
muscle magnetic resonance, electromyography and muscle biopsy. There is no specific treatment. Generally,
BMALL has benign progress, but there are a few cases of poor prognosis. |