Background: Mucosa-associated lymphoid tissue (MALT) lymphoma constitutes approximately 90% of primary pulmonary lymphoma, and the diagnosis of pulmonary MALT lymphoma often requires invasive methods such as surgical lung biopsy. Chromosomal rearrangements involving MALT lymphoma translocation gene 1 (MALT1) have been reported to be specific for MALT lymphoma. The combination of BAL and cytologic approaches with molecular methods is useful for the diagnosis of lymphoproliferative disorders. Therefore, we examined the detection of MALT1 gene rearrangements in BAL fluid (BALF) cells for the diagnosis of MALT lymphoma.
Methods: We determined the percentage of BALF cells with MALT1 gene rearrangements by using the fluorescence in situ hybridization (FISH) method in 10 patients suspected to have pulmonary MALT lymphoma.
Results: MALT1 gene rearrangements in BALF cells were found in four of five cases with pulmonary MALT lymphoma (percentage of BALF cells with MALT1 gene rearrangements: 21.8% ± 6.8%). On the other hand, MALT1 gene rearrangements in BALF cells were negative in the five cases without pulmonary MALT lymphoma and one case with pulmonary MALT lymphoma.
Conclusion: These results suggest that the detection of MALT1 gene rearrangements in BALF cells is useful for the diagnosis of pulmonary MALT lymphoma, as it is a specific method that is less invasive than surgical biopsy. Because of the small number of patients in this study, further investigations are necessary to evaluate the detection rate of MALT1 gene rearrangements in BALF cells from patients with pulmonary MALT lymphoma.