Sign Up for a Free Account
  • Updated 04.16.2023
  • Released 03.11.1994
  • Expires For CME 04.16.2026

Polymyositis, necrotizing autoimmune myositis, myofasciitis, and overlap-myositis


Historical note and terminology

Although first recorded by Wagner in 1863 (150), polymyositis became a recognized clinical entity 75 years later when Walton and Adams published a remarkable monograph titled Polymyositis (151). These authors defined the term “polymyositis” as an all-inclusive designation of a group of myopathies characterized by a single basic disease process related to "other collagen" diseases or arising as the result of "hypersensitivity response to allergic inflammation." Today, described by neurologists as a neuromuscular disorder, polymyositis is cared for not only by neurologists but also by rheumatologists, who approach the illness as in a setting of other rheumatic diseases. Polymyositis is a rare disorder that, by all accounts, is the most overdiagnosed acquired myopathy and, although now unclear whether it exists as a distinct entity, it is discussed not only for historical reasons but also because it is still diagnosed by various practitioners. Although this author believes that it does not exist as a single entity, the evolution and now almost extinction of what was considered as polymyositis 3 to 4 decades ago, has taught us a lot about muscle immunopathology. It is discussed here in the context of two similar but now distinct and more frequent entities, which have evolved in the last two decades, namely necrotizing autoimmune myositis and overlap myositis, while emphasizing its distinction from inclusion body myositis.

The study of polymyositis requires a scholarly review of the neurologic examination, muscle histopathology, immunopathology, and biochemistry to ensure that toxic, metabolic, or mitochondrial muscle diseases are not missed and that the two more common entities, the inclusion body myositis and the necrotizing autoimmune myositis, are not overlooked (12; 73; 29; 30; 36; 37; 39; 46; 47; 49; 132; 40; 114; 46; 46).

This is an article preview.
Start a Free Account
to access the full version.

  • Nearly 3,000 illustrations, including video clips of neurologic disorders.

  • Every article is reviewed by our esteemed Editorial Board for accuracy and currency.

  • Full spectrum of neurology in 1,200 comprehensive articles.

  • Listen to MedLink on the go with Audio versions of each article.

Questions or Comment?

MedLink®, LLC

3525 Del Mar Heights Rd, Ste 304
San Diego, CA 92130-2122

Toll Free (U.S. + Canada): 800-452-2400

US Number: +1-619-640-4660



ISSN: 2831-9125