Adult nemaline myopathy with trabecular muscle fibers

The term "trabecular myopathy" has been used to designate a syndrome resembling limb-girdle muscular dystrophy in which the predominant pathological feature is an abundance of lobulated or trabecular muscle fibers. However, the validity of this nosological entity has not been verified. Herein we describe a 63-year-old man with a severe, progressive myopathy who exhibited the typical pathological features of both trabecular myopathy and nemaline myopathy in association with a biclonal gammopathy. In this case, adult-onset nemaline myopathy was probably the primary disease process. The diagnostic significance of trabecular muscle fibers remains uncertain.