Primary lymphoma of the trachea with morphologic and immunophenotypic characteristics of low-grade B-cell lymphoma of mucosa-associated lymphoid tissue.

A patient with primary extranodal lymphoma arising in the trachea presented with severe upper airway obstruction. The tumor was localized at presentation. The patient has remained disease-free for 12 months following surgical resection and local radiation treatment. The tumor had distinctive morphologic features characteristic of low-grade lymphomas of mucosa-associated lymphoid tissue (MALT), including a diffuse infiltrate of small lymphocytes and centrocyte-like cells surrounding reactive follicles, with plasmacytoid differentiation, and lymphoepithelial lesions. The tumor cells expressed monotypic immunoglobulin but not CD5 or CD10. This case provides evidence that primary lymphomas of the trachea in some cases are tumors of mucosa-associated lymphoid tissue.