title: Prevalence and clinical picture of musculoskeletal sarcoidosis.
abstract: BACKGROUND
  Sarcoidosis is a multisystem disease affecting different organs with different frequency rates depending on geographical location. Musculoskeletal abnormalities includes osseous lesions (small and large bone sarcoidosis), sarcoidal arthropathy, and sarcoidal myopathy. Musculoskeletal involvement is reported in a significant number of patients.
  
  
  OBJECTIVE
  This study aimed to determine the prevalence and clinical picture of musculoskeletal sarcoidosis in Iranian cohort of patients with sarcoidosis.
  
  
  METHODS
  We designed a descriptive cross-sectional study including 30 patients with sarcoidosis who had hospitalized in the Rheumatology Department at Ghaem Hospital, Mashhad, Iran. The patients were evaluated for musculoskeletal symptoms using history, physical examination, and paraclinical data.
  
  
  RESULTS
  Of the 30 studied patients, 24 were female (80%) and six were male (20%). The mean age at diagnosis was 38 years. Sarcoidal arthropathy (arthritis and periarthritis) was observed in 26 patients (86.6%). Furthermore, the initial presentation was associated with joint symptoms in 19 cases (63.3%); acute arthritis developed in 17 (65%) while bone and muscle involvements each occurred in 2 (6.6%).
  
  
  CONCLUSIONS
  Sarcoidosis is a common disease in women aged 20 to 40 years. The most common involved joint were consecutively ankles, knees, and wrists, reaching a accumulated frequency of 86.6%; however, bone and muscle involvements were uncommon.
authors.affiliation: Rheumatic Diseases Research Center, Ghaem Hospital, School of Medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran.
authors.forename: Masoumeh
authors.initials: M
authors.lastname: Salari
authors.affiliation: Rheumatic Diseases Research Center, Ghaem Hospital, School of Medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Rezaieyazdi
keywords: Arthritis; Musculoskeletal Diseases; Sarcoidosis