Detail of pharyngeal tonsils (human)

Stain: Azan. In contrast to the palatine and lingual tonsils, the epipharyngeal tonsil has a ciliated epithelium (1). Islands of multilayered squamous epithelium may interrupt it (transition zone, 2). The epithelium may be infiltrated with lymphocytes. The surface of this tonsil can be enlarged by microfolds rather than by invaginations (not shown here). The lamina propria is almost completely filled with lymphoreticular tissue