Periductal lymphoid infiltrate in the parotid gland of a patient with Sjögren's syndrome

The lymphoid infiltrate shares structural features of secondary lymphoid organs. The immunohistochemical staining shows segregation of T cells (CD3 stain) and B cells (CD20 stain) into discrete areas, with a central B-cell follicle surrounded by T-cell-rich areas. B cells within the follicle are also identified by the Bcl-6 stain. Plasma cells (CD138 stain), sparse in number, have a largely perifollicular location.