Sarcoidois: is it only a mimicker of primary rheumatic disease? A single center experience

Sarcoidosis is known as a T helper 1 lymphocyte (Th1-Ly) mediated disease which can imitate or sometimes accompany many primary rheumatic diseases. The purpose of this study is to share the clinical, demographic and laboratory data of patients presenting with rheumatologic manifestations and diagnosed with sarcoidosis.

A total of 42 patients (10 men) were included in the study. The patients were admitted to the rheumatology outpatient clinic for the first time with different rheumatic complaints between November 2011 and May 2013 and were diagnosed with sarcoidosis after relevant tests. Clinical, demographic, laboratory, radiological and histological data of these patients were collected during the 18-month follow-up period and then analyzed.

Mean patient age was 45.2 years (20-70 years) and mean duration of disease was 3.5 years (1 month-25 years). Evaluation of system and organ involvement revealed that 20 (47.6%) patients had erythema nodosum, 3 (7.1%) had uveitis, 1 (2.3%) had myositis, 1 (2.3%) had neurosarcoidosis, 32 (76.2%) had arthritis and 40 (95.2%) had arthralgia. Of the 32 patients with arthritis, 28 (87.5%) had involvement of the ankle, 3 (9.4%) had involvement of the knee and 1 (3.2%) had involvement of the wrist. No patient had cardiac involvement. Thoracic computed tomography scan showed stage 1, 2, 3 and 4 sarcoidosis in 12 (28.5%), 22 (52.4%), 4 (9.5%) and 4 (9.5%) patients, respectively. Histopathology of sarcoidosis was verified by endobronchial ultrasound, mediastinoscopy and skin and axillary biopsy of lymphadenopathies, which revealed noncaseating granulomas. Laboratory tests showed elevated serum angiotensin-converting enzyme in 15 (35.7%) patients, elevated serum calcium level in 6 (14.2%) patients and elevated serum 1,25-dihydroxyvitamin D concentrations in 2 (4.7%) patients. Serological tests showed antinuclear antibody positivity in 12 (28.5%) patients, rheumatoid factor positivity in 7 (16.6%) patients and anticyclic citrullinated antibody positivity in 2 (4.8%) patients.

Sarcoidosis can imitate or accompany many primary rheumatic diseases. Sarcoidosis should be considered not simply as an imitator but as a primary rheumatic pathology mediated by Th1-Ly. New studies are warranted on this subject.