MUCOSAL - ASSOCIATED LYMPHATIC TISSUE (MALT)

Lymphatic tissue is often found in the lamina propria underlying mucous membranes (those membranes lining cavities which have openings to the outside of the body). This lymphatic tissue can assume three forms: diffuse lymphatic tissue, solitary lymphatic nodules and aggregated lymphatic nodules, the latter being present in the small intestine (Peyer’s patches), the vermiform appendix, and tonsils.

Tonsil, Palatine (H&E) [#38]: This lymphoid organ has no complete capsule or trabeculae. It consists of a collection of nodules, some of which contain germinal centers (arrows), which are lighter staining areas. The tonsil is covered on its free surface by a stratified squamous non-keratinized epithelium which penetrates deeply through the lymphoid tissue of the tonsil to form crypts lined by the same type of epithelium. In some areas, the epithelium is infiltrated with lymphocytes (presumably on their way to the oral cavity).

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	Slide Text MUCOSAL - ASSOCIATED LYMPHATIC TISSUE (MALT) Lymphatic tissue is often found in the lamina propria underlying mucous membranes (those membranes lining cavities which have openings to the outside of the body). This lymphatic tissue can assume three forms: diffuse lymphatic tissue, solitary lymphatic nodules and aggregated lymphatic nodules, the latter being present in the small intestine (Peyer’s patches), the vermiform appendix, and tonsils. Tonsil, Palatine (H&E) [#38]: This lymphoid organ has no complete capsule or trabeculae. It consists of a collection of nodules, some of which contain germinal centers (arrows), which are lighter staining areas. The tonsil is covered on its free surface by a stratified squamous non-keratinized epithelium which penetrates deeply through the lymphoid tissue of the tonsil to form crypts lined by the same type of epithelium. In some areas, the epithelium is infiltrated with lymphocytes (presumably on their way to the oral cavity).