Sarcoidosis or Sjögren syndrome? Clues to defining mimicry or coexistence in 59 cases.

We present 5 new cases of coexisting sarcoidosis and Sjögren syndrome (SS) and review the literature for additional cases in order to analyze the clinical, immunologic, and histologic characteristics that may help physicians differentiate the mimicry of SS by sarcoidosis from a true coexistence of both autoimmune diseases. We considered the coexistence of sarcoidosis with SS to be when patients presented specific histologic patterns of both diseases, simultaneously or at different times.Fifty-nine patients were included in the analysis (54 identified in the literature search plus our 5 unpublished cases): 49 (83%) patients were female and 10 (17%) were male, with a mean age at diagnosis of 50 years. According to the histopathologic examination of the exocrine glands performed in 53 cases, we defined coexistence of sarcoidosis and SS in 28 cases, while in the remaining 25 patients, sarcoidosis mimicked SS. Clues to identifying when sarcoidosis coexists with SS were a higher prevalence of systemic manifestations (arthritis and uveitis) and positive immunologic parameters (antinuclear antibodies, rheumatoid factor, and anti-Ro/SS-A), as well as the existence of a focal sialadenitis (Chisholm-Mason score grades III-IV, with a CD4+ lymphocytic infiltration) in the salivary gland biopsy. In patients first diagnosed with primary SS, the appearance of some clinical features such as hilar adenopathies, uveitis, or hypercalcemia leads to the diagnosis of coexisting sarcoidosis. A careful application of the new American-European consensus criteria had a sensitivity of 93% and a specificity of 92% in identifying when SS coexists with sarcoidosis.In conclusion, the association of sarcoidosis with SS leads to a true coexistence of both diseases in more than half the patients described in the literature, while in the remaining patients, sarcoidosis mimics SS. In light of these results, sarcoidosis should not be considered as an exclusion criterion for the diagnosis of SS, and in patients with a suspected overlap of the two diseases, application of the new American-European consensus criteria for diagnosis of SS should be mandatory.