[Lymphoid lesions of the head and neck]

Lymphoid lesions of the head and neck mainly affect four regions: Waldeyer's ring, nasal and paranasal sinus, oral cavity and salivary glands. Each site is affected by lymphoid proliferation that reflected the biology of local lymphocytes. Waldeyer's ring, functionally similar to the mucosal associated lymphoid tissue of the gastrointestinal tract is most commonly affected by large B-cell lymphomas. The nasal cavity and paranasal sinuses are the typical site of extranodal NK/T-cell lymphoma, nasal type, a proliferation of cytotoxic, EBV infected cells. This lesion is sometimes difficult to distinguish from inflammatory processes as Wegener disease. Plasmablastic lymphoma have been first described in oral cavity in HIV patients. Endemic Burkitt lymphoma, considered as a polymicrobial disease associated with the t(14;18) translocation presented in the great majority of cases as a jaw tumor with oral extension. Salivary glands, not normally containing lymphoid tissue are the site of lymphoepithelial sialadenitis associated to Sjögren syndrome. It represents a pre lymphomatous state of marginal zone lymphoma. These different lymphoproliferations serve as a model for mechanisms of lymphomagenesis.