Cervicomedullary astrocytoma simulating a neuromuscular disorder

A 12-year-old male developed progressive proximal upper extremity weakness over a 3- to 4-year period. The clinical findings of proximal upper extremity weakness and atrophy, prominent scapular winging, and no sensory deficits or upper motor neuron signs suggested a neuromuscular disorder. Electromyography was consistent with a chronic denervating disorder involving the upper cervical anterior horn cells or their axons. A cervical magnetic resonance image revealed a large intramedullary mass extending from the inferior aspect of the fourth ventricle down to the level of T2. A biopsy of the lesion was consistent with a low-grade astrocytoma.