Figure 2

This is a low power view of lesional tissue showing cystic spaces lined by squamous type epithelium with lymphoid tissue including a germinal centre on the right. These cysts show a mixture of squamous and ductal type epithelial lining with prominent infiltration by small lymphocytes. The Inset (top right corner) is low power view of a H&E stained slide showing ductal structures surrounded by blood vessels with abundant lymphoid tissue in the adjacent stroma. Scattered small islands of epithelium are identified in the lymphoid stroma. These represent branchial pouch-derived inclusions which proliferate to form cysts under the influence of growth factors produced by the hyperplastic lymphoid tissue. In line with the lymph node inclusion theory, some of these consist of pink staining oncocytic epithelium of the type as seen in Warthin’s tumours.F