Tubular aggregate myopathy: A phenotypic spectrum and morphological study

摘要

Tubular aggregates (TAs) are inclusions described in skeletal muscle in a variety of disorders. In a retrospective analysis, TAs were found in 18 (0.24%) cases and involved a spectrum of clinical phenotypes. Ultrastructurally, four distinct types,of aggregates were noted. There was no correlation between the clinical phenotypes, duration of illness and types of TAs. Tubular aggregates (TAs), inclusions in skeletal muscle derived from sarcoplasmic reticulum, are ultrastructurally characterized by accumulation of densely packed membranous tubules. They are uncommon but an important indicator of myopathies. Initially described by Engel in a case of hypokalemic periodic paralysis and myotonia congenita, TAs are presently known to occur in a wide variety of conditions, and in male inbred mice during aging and can be induced experimentally. However, in several cases, TAs constitute the cardinal structural pathology indicating myopathy with TAs as a distinct entity. In the present study, 18 cases with TAs seen over a period of 10 years were reviewed to determine the spectrum of clinical phenotypes associated with these distinctive inclusions and morphological types of TAs encountered. An attempt was made to correlate clinical phenotypes, duration of illness and ultrastructural types of TAs.