Primary Sjögren's syndrome complicated by sarcoidosis and psoriasis vulgaris.

Abstract Primary Sjögren's syndrome (SS), sarcoidosis (SA), and psoriasis vulgaris (PV) are all chronic diseases of unknown etiology. Recent studies suggest that activated T cells play a central role in their pathogenesis. We describe a case of a Japanese woman with primary SS complicated by SA and PV. To our knowledge, this is the first case in which these three diseases coexist. Although these three disorders may have a common immunopathogenic mechanism, the extreme rarity of their coexistence suggests that distinct etiological mechanisms are also involved and appear to play an important role in triggering and developing each disease.