1 Pediatric Hematology Oncology, Azienda Ospedaliera Universitaria Integrata, Verona, Italy.
2 Department of Neurosciences, Biomedicine and Movement Sciences, Section of Clinical Neurology, University of Verona, Italy.
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Chronic graft versus host disease (cGVHD) occurs in 20-30% of
paediatric patients receiving haemopoietic stem cell transplantation
(HSCT). Neuromuscular disorders such as polymyositis are considered a
rare and distinctive but non-diagnostic manifestation of cGVHD and, in
the absence of other characteristic signs and symptoms, biopsy is
highly recommended to exclude other causes.
|Figure 1. Light microscopy of muscle biopsy. Hematoxylin and eosin stain shows necrotic, degenerating and regenerating muscle fibers (A) and a large inflammatory infiltrate around vessels (B). ATPase reactions showed normal differentiation and distribution of muscle fibers and no increase of perimysial or endomysial connective tissue was observed. All other histochemical stains were normal.|
|Figure 2. Immunohistochemistry of muscle biopsy. Serial muscle fiber sections (hematoxylin and eosin) showing mononuclear inflammatory cells (A) which are predominantly composed of CD8+ T cells (B); a few CD4+ T cells (C) and CD57+ NK cells (D), and rare CD68+ macrophages (E) and CD20+ B cells (F). Major histocompatibility complex (MHC) class I antigen was upregulated on the sarcolemma of many muscle fibers and membrane attack complex (MAC) deposits were detected on the wall of few capillaries.|