Significance of Nonspecific Structures Present in Diagnostic Muscle Biopsies in Electron Microscopy: A Study of 168 Cases

On a routine examination of 168 muscle biopsies by transmission electron microscopy, we observed various structures, like filamentous bodies in 49 cases (29%), tubular aggregates in 22 (13%), paracrystalline inclusions in 15 (9%), honeycomb arrays in 11 (6.5%), concentric laminated bodies in 10 (6%), fingerprint bodies in 6 (3.8%), and fibrous nuclear inclusions in 3 (1.8%), for a total of 116/168 or a 70% occurrence. In order to evaluate the significance and occurrence of these structures in muscle biopsies, we correlated the clinical features, light microscopic and histochemical findings on these patients.168 muscle biopsies were studied. The muscle biopsy was obtained by using the conventional muscle clamp in all the cases. After obtaining the muscle biopsy in each case, about 1/3 of the length was frozen in liquid nitrogen at -170 degrees F to be used for histochemistry. The second 1/3 was fixed in formalin for paraffin section, and the remaining 1/3 was minced in small pieces and fixed in 2.5% glutaraldehyde for electron microscopy study.

Chronic Benign Congenital Myopathy: Fingerprint Body Type

SUMMARYThe term “benign congenital myopathy” describes a group of muscle disorders characterized by proximal or diffuse muscle weakness, a relatively non-progressive course, normal serum muscle enzyme assays and the presence of a distinctive morphological feature. We report here a 55 year old woman, with fingerprint body myopathy who exhibits all of the above features. She has been affected from birth, able to walk since the age of 12, and has not deteriorated in the past thirty years. Muscle biopsy reveals fatty infiltration, numerous small fibers undergoing structural change, good differentiation into type I and II fibers, and excessive intracellular lipid and lipochrome. Only on electron microscopic study is the distinctive feature of numerous subsarcolemmal round to ovoid fingerprint bodies observed. Many fibers also contain large collections of tubular aggregates, filamentous bodies, and autophagic vacuoles.The fingerprint bodies are similar to the ones described by A. Engel in a 5 year old girl. Thus, a rare opportunity is provided to study an individual who has had this disease for over fifty years.