[Patient with chronic sarcoid myopathy without other organ involvement]

We herein report the patient of a 69-year-old woman who presented with the chronic myopathic form of sarcoid myopathy. She had experienced slowly progressive limb muscle weakness for three years. She was found to be thin, but otherwise normal, on a physical examination. Neurologically, proximal muscles are predominantly involved without any sensory or other focal deficits. Electromyography revealed myopathic motor unit potentials exhibiting spontaneous discharge. Muscle biopsy demonstrated extensive connective tissue and few residual muscle fibers with a hint of granuloma formation. Repeated sectioning of the muscle biopsy revealed noncaseatious granuloma with a multinucleated giant cell, confirming the diagnosis. The findings of all imaging studies, including a systemic PET (positron emission tomography) scan, were unremarkable. Without careful pathological observation with repeated sectioning, this patient would have been misdiagnosed with limb-girdle muscular dystrophy