A case of scapuloperoneal atrophy with rigid spine having lobulated fibers in muscle biopsy

The patient, a 52-year-old male, noticed abnormalities on walking at about 20 years of age, followed by slowly progressive muscle weakness of arms and neck. The family history was negative. He showed muscular atrophy and weakness with a preferential involvement of the scapular, arms and peroneal muscles. Deep tendon reflexes were absent. He had a limited range of motion in the spine, but the onset was unclear. Creatine kinase (CK) was elevated (324 IU/L) and the EMG study showed myogenic pattern. Muscle biopsy was obtained from the biceps brachii muscle; on NADH dehydrogenase stain, there was subsarcolemmal increase in the oxidative enzyme activity showing "lobulated fiber" mostly seen in type 1 fibers. On electron-microscopy, the sub-sarcoplasmic areas which had high NADH activity, contained many mitochondria and glycogen particles. However, iodine-glycogen complex spectrum analysis pattern and debranching enzyme activity were normal. CT scan revealed low density in the paravertebral muscles, suggesting degeneration. This is a rare type of scapuloperoneal atrophy different from Emery-Dreifuss syndrome, rigid spine syndrome and FSH type muscular dystrophy.