Mucosa-associated lymphoid tissue (MALT) lymphomas are indolent neopla
sms which tend to remain localized for a long time before spreading. W
e describe here the case of a 36-year-old woman with a low-grade MALT
lymphoma involving the lung, stomach, lingual tonsil? and bone marrow
at the time of diagnosis. The clonal origin of the pulmonary and bone
marrow neoplastic infiltrates was assessed by means of gene rearrangem
ent analysis. All of the involved sites were infiltrated by centrocyte
- and monocytoid-like cells expressing the B-cell-associated antigens
CD19 and CD20 and showed IgM lambda chain restriction; no CD5, CD10, o
r CD43 expression was detectable. As the patient had a history of recu
rrent bronchitis, and computed tomography performed 3 years before the
lymphoma diagnosis had already revealed a lesion of the left lung, we
conclude that the present case probably represents a pulmonary low-gr
ade MALT lymphoma characterized by an early and unusual involvement of
different mucosal sites and bone marrow.