A study of morphometric and histopathological features of muscle biopsies from patients of myopathy.

The aim of this study is to analyse the morphological pattern of different types of myopathies including morphometric data. The cases were diagnosed as myopathy on the basis of clinical details, EMG findings, serum CK values. Muscle biopsies were performed and hematoxylin & eosin stain and Masson's trichrome stain were done. Muscle fiber diameters were measured using an eye piece micrometer of 100 fibers in each biopsy, these values were plotted and histograms were constructed. From this, mean fiber diameter (MFD), standard Deviation (SD), atrophy factor (AF), hypertrophy factor (HF) and variability coefficient (VC) were calculated. Degree of inflammation was scored semiquantitatively and presence of degenerating fibers, regenerating fibers, perifascicular atrophy, perivascular lymphocytic infiltration and vasculitis were noted. Out of 25 patients, 9 patients of inflammatory myopathy were adults, of the 16 patients of dystrophy 9 patients were adults. Along with weakness of limbs, skin rash was seen in 2 patients of dermatomyositis. Degree of inflammation was more in the patients of inflammatory myopathy than in the patients of dystrophy. Necrotic and regenerating fibers were seen in both groups. Perifascicular atrophy was seen in 1 case of dermatomyositis. Atrophy factor was higher in cases of dystrophy and so was hypertrophy factor. Variability coefficient >250 was found on 90% of dystrophy cases and it was <250 in the cases of inflammatory myopathy. Morphometry provides valuable data, which helps in distinguishing dystrophy from cases of myopathy with inflammation.