Pathological features of inflammatory myopathy as a manifestation of chronic graft‐versus‐host disease after allogeneic bone marrow transplantation.

Chronic graft‐versus‐host disease (cGVHD) is the most important complication resulting in the death of bone marrow transplantation (BMT) survivors. It is also a relatively rare cause of inflammatory myopathy (IM). We report the case of a 46‐year‐old woman who developed severe cGVHD‐related IM after BMT for myelodysplastic syndrome. She presented with severe muscle pain and weakness with cGVHD‐related symptoms in other organs. Myopathological analysis showed moderate cell infiltration with remarkable necrotic and regenerative fibers. Sarcoplasm and capillaries expressed C5b9 and myxovirus resistance protein 1. Non‐necrotic fibers in perifascicular regions expressed MHC‐II. Steroid therapy did not sufficiently control cGVHD‐related IM, and the patient was concurrently treated with an immunosuppressant. Our findings show that IM is a key manifestation of cGVHD and that the expression of interferon‐inducible proteins in muscle pathology is useful for identifying cGVHD‐related IM. [ABSTRACT FROM AUTHOR]