Abstract

Myofibrillar myopathies (MFMs) are a genetically or clinically heterogeneous group of diseases that are characterized by focal myofibrillar dissolution associated with accumulation of myofibrillar degradation products and ectopic expression of multiple proteins. Since MFMs show morphologically distinct features but consist of genetically and clinically heterogeneous diseases, muscle biopsy is important for the diagnosis. A 20-year-old man complained of progressive weakness and atrophy of both legs for two years. He had a dysmorphic face and short stature. The light microscopic examination of his muscle biopsy showed mixed myopathic and neurogenic changes. Many myofibers with multiple clusters of blue red rod-like structures and cytoplasmic inclusions were noted. Immunohistochemistry showed a focal positive reaction in sarcoplasm to desmin and myotilin antibodies. An electron microscope study revealed variable abnormalities of myofibrillar structures. To the best of our knowledge, this is the first reported case of MFM with pathology findings in Korea.

• Keywords: Myofibrillar myopathies;Desmin;Pathology