Mucosa-associated lymphoid tissue in human efferent tear ducts.

The recent description of primary marginal zone lymphomas in human efferent tear ducts with typical features of lymphomas arising in mucosa-associated lymphoid tissue (MALT) infers the presence of MALT in the human efferent tear ducts. To date, studies have not established clearly whether organised MALT occurs in normal human efferent tear ducts. To elucidate this problem, efferent lacrimal pathways from unselected body donors with unknown prior history of efferent tear duct, ocular, or nasal disease were examined for the presence of organised MALT. Organised lymphoid tissue was found with the cytomorphological and immunophenotypic features of MALT in 41% of the cases examined. These findings suggest that MALT is a feature that, although it need not be present in normal efferent tear ducts, is acquired during life in a proportion of apparently asymptomatic individuals.