Adult-onset lower extremity weakness caused by venous malformation detected by magnetic resonance imaging.

ABSTRACT

INTRODUCTION: Symptomatic venous malformation (VM) of muscle in adults is rare and usually presents in childhood or adolescence as the individual is growing. We describe an atypical presentation of a malformation affecting the gastrocnemius muscle asymmetrically with onset in adulthood, which created a diagnostic challenge. Electromyography (EMG) and muscle biopsy did not fit clinically and MRI of the gastrocnemius led to the diagnosis. METHODS: The setting for the patient studied was a neuromuscular outpatient clinic. RESULTS: EMG showed decreased insertional activity and motor unit potential recruitment in the right gastrocnemius muscle. Muscle biopsy showed mild neurogenic changes. MRI demonstrated VM in the contralateral gastrocnemius muscle. CONCLUSIONS: This case represents a rare cause of atrophic weakness in adults, but muscle MRI should be considered when other tests are equivocal.