Polymyositis, a very uncommon isolated disease: clinical and histological re-evaluation after long-term follow-up

• Published in: Rheumatology international Vol. 35; no. 5; pp. 915 - 920
• Main Authors: Vilela, Veronica Silva, Prieto-González, Sergio, Milisenda, José C., Selva-O´Callaghan, Albert, Grau, Josep M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2015; Springer Nature B.V
• Subjects: Adult; Aged; Autoimmune Diseases - complications; Autoimmune Diseases - diagnosis; Cohort Studies; Connective Tissue Diseases - complications; Connective Tissue Diseases - diagnosis; Databases, Factual; Diagnosis, Differential; Disease Progression; Drug-Related Side Effects and Adverse Reactions - diagnosis; Female; Follow-Up Studies; Humans; Male; Medicine; Medicine & Public Health; Middle Aged; Muscle, Skeletal - pathology; Myositis - diagnosis; Myositis - etiology; Myositis, Inclusion Body - diagnosis; Neoplasms - complications; Neoplasms - diagnosis; Original Article - Cases with a Message; Polymyositis - diagnosis; Polymyositis - etiology; Retrospective Studies; Rheumatology; Virus Diseases - complications; Virus Diseases - diagnosis; Young Adult; Idiopathic inflammatory myopathy; Inclusion body myositis; Necrotizing autoimmune myopathy; Connective tissue disease; Polymyositis
• ISSN: 0172-8172; 1437-160X
• DOI: 10.1007/s00296-014-3198-5

The aim of the present study was to explore whether polymyositis may be considered as an isolated, organ-specific disease or more suitably as a secondary or associated entity. A retrospective re-evaluation of all the muscle biopsies performed at the Hospital Clínic of Barcelona showing histopathological pattern of polymyositis from January 1997 to May 2012 was carried out. The medical records of the patients with the aforementioned pathological pattern were also reviewed. From 1.290 muscle biopsies performed during the period evaluated, 36 with polymyositis pattern were identified. At the time of muscle biopsy, polymyositis pattern was secondary or associated with other disease in 26 patients and was classified as isolated in the remaining ten patients. After pathological re-evaluation and long-term clinical follow-up, only one patient remained with this diagnosis. Overall, the main final diagnosis related to the initial polymyositis pattern was inflammatory myopathy associated with connective tissue disease. Several other associated conditions were also identified. Isolated polymyositis is highly uncommon. Ruling out potential associated or confusing entities, like inclusion body myositis, overlap syndromes, infections, and cancer, is mandatory.