Image analysis of fatty infiltration in labial salivary gland biopsies: extent and its correlation to age, obesity and diabetes
Minor salivary gland (MSG) biopsy is a useful, accepted and rather safe method in the diagnosis of Sjögren's syndrome (SS). The importance of the quality and quantity of lymphocytic infiltration has been shown in numerous studies1. Grading of the inflammatory infiltrate made by Chisholm is still the gold standard for the diagnosis 1. Although inflammatory infiltration is an important phenomenon in the biopsy specimens, much less is known about other, relatively frequent histological changes like fibrosis (2) and fatty infiltration 6. Most of the studies agree that fatty infiltration is likely to be age‐dependent change suggesting that it has no specific connection to any particular autoimmune diseases or histopathological changes like inflammation 8; however, Friedman et al. 6 examining several histological changes in MSGs of patients with different autoimmune diseases found that the fibrosis is more common in systemic lupus erythematosus (SLE) and systemic sclerosis (SSc), while fatty infiltration was more frequent in rheumatoid arthritis (RA) patients and spared the SSc group. Also, Skarstein et al. 14 indicated significantly higher incidence of fatty infiltration in SS than in the control group.
The aim of this study was to determine the frequency and to quantify the amount of fatty infiltration in labial salivary gland biopsy samples within the population who had this biopsy procedure and to find a correlation with the supposed causes. Fatty infiltration is not unknown in other organs and tissues like myocardium 16, pancreas 17 and the parotid gland 9. In these cases, obesity is considered to be an important factor. Increasing age was shown as a possible explanation of fatty infiltration 13 in some cases, and significant correlation between the age and fatty infiltration has been found in few studies 8. Two other partly related factors like the obesity and the diabetes mellitus were also implicated, but their role in the pathogenesis of fatty infiltration in MSG biopsies was not examined in details 9.