Calf-head sign in Miyoshi myopathy

Abstract

Objective: To observe whether patients with Miyoshi-type dysferlinopathy demonstrate any distinct appearance in the back of the shoulders and upper back in a specific posture.

Design: Case series.

Setting: Neurology outpatient clinic of a north Indian tertiary care medical institute.

Patients: Fifteen patients from 9 families (10 males and 5 females; age range, 16-42 years) who had Miyoshi myopathy with onset of calf and shin muscle wasting between the ages of 9 and 28 years and a myopathic pattern at electromyography, moderately high serum creatine kinase levels, and absence of dysferlin at immunohistochemical staining.

Interventions: Patients were asked to raise their arms with shoulders abducted and elbows flexed to 90 degrees . All were observed from behind for the morphological change in the bulk of different muscles of the upper back and shoulders. T1-weighted magnetic resonance imaging of the upper thorax and shoulder was performed in an oblique sagittal plane to confirm the clinical findings.

Main outcome measure: Consistent pattern of muscle enlargement or wasting seen clinically and at magnetic resonance imaging that produces a particular diagnostic appearance.

Results: A characteristic appearance was observed on the upper back and shoulders that could be described as calf heads on a trophy sign. The sign was clearly visible in 6 patients, whereas it was present in a subtle manner in another 4. Some but not all components of the sign were visible in the rest of the patients.

Conclusion: The calf heads on a trophy sign may be useful in identifying most patients with Miyoshi-type dysferlinopathy.