Regional Ischemic Immune Myopathy: A Paraneoplastic Dermatomyopathy

Abstract

Necrosis and regeneration of scattered muscle fibers are common features of many active acquired and immune myopathies. We studied a series of patients with acquired myopathies with an unusual pattern of regional, rather than scattered, muscle fiber necrosis and regeneration. Retrospective review of records of 7 patients with acquired myopathies having regional muscle fiber necrosis on muscle biopsy. Clinical features of patients included proximal symmetric weakness in arms and legs with a subacute onset (100%) beginning at ages between 41 and 92 years, with dysphagia (83%), myalgias (100%), skin rash (67%), and associated malignancy (71%). Serum creatine kinase was often very high (>1,600 U/L) (83%). Survival was less than 1 year in 43%. Myopathology included a regional distribution with muscle fiber necrosis and capillary loss in the border zones between intermediate-sized perimysial vessels, vascular pathology with damaged walls of intermediate-sized perimysial veins, and connective tissue with expression of the ischemia marker carbonic anhydrase IX but no mononuclear cell inflammatory foci. These data indicate that regional ischemic immune myopathies are likely caused by ischemia in border zones between damaged intermediate-sized perimysial blood vessels. Regional ischemic immune myopathies are a distinctive pathologic group of acquired, probably immune, noninflammatory dermatomyopathies with weakness and often a skin rash and systemic neoplasm.

Histological heterogeneity in a large clinical cohort of juvenile idiopathic inflammatory myopathy: analysis by myositis autoantibody and pathological features

“…Similar patterns are present in this paediatric cohort, in small numbers in several serological groups. CN was previously reported as a characteristic of regional ischemic immune myopathy and was suspected to be associated with NXP2 autoantibodies in the original series . Our data suggest a similar association in juvenile IIMs.…”

“…The rare myopathological manifestations of MSA‐associated inflammatory myopathies are an interesting group in our cohort. Previous publications on these are available mostly as small series of adult patients with pathologies such as macrophage rich inflammation and clusters of necrotic fibres . Similar patterns are present in this paediatric cohort, in small numbers in several serological groups.…”

“…The aim of the histological review was a descriptive assessment of the dominant pathological features in each muscle biopsy. Groups were largely based on findings described in the context of typical myopathological diagnoses, such as perifascicular atrophy (PFA) in classic dermatomyositis, macrophage rich necrosis in IMAM , inflammatory fibre invasion (FI) in inclusion body myositis, scattered necrosis (SN) in immune mediated necrotizing myopathies, and clustered necrosis (CN) in regional ischemic immune myopathy . It is important to emphasize that we wish to distinguish between descriptive histological groups used for this study and the diagnostic entities related to them.…”

“…Several rare and less well‐correlated myopathological manifestations of inflammatory muscle disease have been described in addition to the more frequent patterns, including inflammatory myopathy with abundant macrophages (IMAM) and regional infarct‐like change . Furthermore, in clinical practice, muscle biopsies often have variable or nonspecific findings in children clinically suspected to have an immune‐mediated condition.…”

Myopathy with anti-HMGCR antibodies

“… 12 , 17 The patterns of scattered necrosis differ from the clusters of muscle fibers in similar stages of necrosis seen in regional ischemic immune myopathy, which is likely due to vascular pathology. 19 …”