The role of electron microscopy in the assessment of dermatomyositis

The role of electron microscopy in the assessment of dermatomyositis 1 2 Dr Hisham Alkhalidi 3 Assistant Professor and Consultant Pathologist Department of Pathology (32) College of 4 Medicine King Saud University P.O. Box 2925 Riyadh 11461 Saudi Arabia Telephone: 5 +966-533408611 Fax: +966-1-4672462 6 [email protected] 7 8 9 Abstract 10 11 Aim: To assess the importance of electron microscopy in the diagnosis of dermatomyositis. 12 Methods: A prospective review of muscle biopsy cases suspected of dermatomyositis from 13 January 2008 to January 2012 in the Pathology Department of King Khalid University 14 Hospital, King Saud University, Riyadh, Saudi Arabia. Samples from each case were 15 reviewed for light and ultrastructural examination. Tubuloreticular inclusions (TRI) were 16 considered present if these undulating tubules were detected in the endothelial cells of the 17 capillaries. 18 Results: Out of ten cases that were suspected for dermatomyositis, three cases showed 19 classical light microscopic features of dermatomyositis, two of which showed TRI. Among 20 four cases with features suggestive of dermatomyositis, TRI were detected in two of these 21 four cases. TRI were detected in three cases out of three where the light microscopy was not 22 diagnostic or even suggestive. 23 Conclusion: The need for electron microscopy in the screening of muscle biopsies, 24 particularly in clinically suspected inflammatory myopathies should be considered, since the 25 presence of TRI may aid in the diagnosis of dermatomyositis. 26