Diagnostic value of additional histopathological fascia examination in idiopathic inflammatory myopathies

Abstract

Background and purposeCorrect diagnosis of idiopathic inflammatory myopathies (IIM) may prevent harm from both lack of treatment in IIM patients and unnecessary treatment in non‐IIM patients. However, it is unknown whether additional histopathological fascia examination may contribute to diagnosing IIM.MethodsThirty‐two magnetic resonance imaging guided en bloc biopsies from patients diagnosed with IIM (except inclusion body myositis) from 2010 to 2017 were reviewed: dermatomyositis (DM) (n = 6), non‐specific/overlap myositis (NM/OM) (n = 11), immune‐mediated necrotizing myopathy (n = 12) and anti‐synthetase syndrome (n = 3). Muscle biopsy specimens were examined according to the 2004 European Neuromuscular Centre (ENMC) criteria. Fascia was subsequently examined for the presence of lymphocytic infiltrates. Isolated fascia involvement was defined as the presence of lymphocytic infiltrates in the fascia/epimysium on histopathology in the absence of any ENMC muscle histopathology/immunohistochemistry criteria.ResultsOne patient with DM (17%) and one patient with NM/OM (9%) had isolated fascia involvement. One patient with immune‐mediated necrotizing myopathy (8%) and one patient with anti‐synthetase syndrome (33%) had fascia involvement, albeit in combination with muscle involvement.ConclusionHistopathological fascia examination may contribute to early diagnosis of DM and NM/OM in a small proportion of patients.

Comprehensive transcriptomic analysis and machine learning reveal unique gene expression profiles in patients with immune‐mediated necrotizing myopathy

“…To some extent, the immunopathological results obtained by muscle biopsy play a decisive role in classification and diagnosis of IIMs, which in turn has great guiding significance for the next step of treatment and prognosis. 4 Muscle biopsy of IMNM displays prominent necrosis and regeneration of muscle fibers with mild or absent inflammatory infiltrates. 5 In recent years, several research groups have carried out research on the pathogenesis of serum-positive IMNM.…”

“…The gold standard for diagnosing muscle diseases is muscle biopsy, which is then confirmed through histopathological examination. To some extent, the immunopathological results obtained by muscle biopsy play a decisive role in classification and diagnosis of IIMs, which in turn has great guiding significance for the next step of treatment and prognosis 4 . Muscle biopsy of IMNM displays prominent necrosis and regeneration of muscle fibers with mild or absent inflammatory infiltrates 5 .…”

Aberrant expression of cell‐free nucleosomes in dermatomyositis/polymyositis

“…Dermatomyositis (DM) and polymyositis (PM) consist of a spectrum of rare and heterogeneous autoimmune myositis, which is characterized by proximal symmetric muscle weakness, visceral organ involvement, and paraneoplastic syndrome 1 . Interstitial lung disease (ILD) is the leading cause of mortality and morbidity in DM and PM (DM/PM), accounting for nearly 80% of the myositis mortality 2,3 .…”

Additional histopathological fascia examination in idiopathic inflammatory myopathies; methodological issues on diagnostic value

“…I read a recently published article in the European Journal of Neurology by Lim et al (2019 [1]. The correct diagnosis of idiopathic inflammatory myopathies (IIM) may prevent harm from both lack of treatment in IIM patients and unnecessary treatment in non-IIM patients.…”