Histopathology of salivary glands

Salivary gland (SG) biopsy is a technique broadly applied for the diagnosis of primary Sjögren's syndrome (pSS), lymphoma accompanying SS, sarcoidosis, amyloidosis, and IgG4-related disease The most peculiar feature of pSS on biopsy is focal lymphocytic sialadenitis. In the past, several histological scores have been reported in the literature to describe glandular involvement during pSS. However, the variability among centres in reporting glandular scores is one of the rationales behind the development of standardised consensus guidance. SGs as well as lacrimal glands are involved in up to 50% of patients with IgG4-related disease with 3 histopathological hallmarks such as dense lymphoplasmacytic infiltration, storiform fibrosis and obliterative phlebitis. SGs can be also affected by amyloidosis with MSG biopsy being more sensitive than that of rectal mucosa or subcutaneous fat. SG involvement is a rare manifestation during sarcoidosis, and the presence of non-caseating granulomas needs to be differentiated from granulomas of other etiology. This review article provides an overview of normal and pathological SGs in the context of rheumatic diseases, identifying key elements in the tissue as diagnostic and prognostic biomarkers, useful in the current clinical practice.