Rare forms of inflammatory myopathies - part II, localized forms

ABSTRACT

Introduction

The idiopathic inflammatory myopathies traditionally comprise dermatomyositis, polymyositis, the anti-synthetase syndromes, immune-mediated necrotizing myopathy and inclusion body myositis. However, there are uncommon localized forms that are less known. In this review, we aimed to cover these uncommon forms.

Areas covered

We identified rare forms of localized myositis on the basis of list provided by the homepage of the Neuromuscular disease center of Washington University, USA and on the basis of the authors’ knowledge. We searched PubMed® for relevant articles on these forms with the aim of providing as much as possible information on their clinical manifestations as well as guidance on their work-up and treatment.

Expert opinion

herein, we provide un updated description of rare forms of localized myositis. These forms are often difficult to diagnose because of their localized nature and are sometimes misdiagnosed as tumors. Knowledge about these rare forms of localized myositis can aid in their recognition and treatment.

KEYWORDS:

• Focal myositis
• orbital myositis
• eosinophilic myositis
• macrophagic myofasciitis

Article highlights

• Myositis comprises some rare forms

• Some rare forms of myositis are localized, such as focal and orbital myositis

• Localized myositis may not be associated with raised muscle enzyme levels

• Localized myositis may be misdiagnosed as tumor

• Knowledge about the rare forms of localized myositis is essential to their recognition and tailored treatment

Declaration of interest

C Salvarani received consulting and investigator fees from Abbvie, Pfizer, MSD, Roche, Celgene, Novartis. N Pipitone received consulting and investigator fees from UCB, Fininvest, AIM group, I&C, Uptodate, Janssen-Cilag, Servier, GSK, AIFA, Foreum, Adienne. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.