Dissemination patterns in non-gastric MALT lymphoma.

Background: In contrast to gastric extranodal marginal zone mucosa associated lymphoid tissue (MALT) lymphomas, there is little consensus on the value and clinical consequences of extensive staging at diagnosis and during follow-up in non-gastric MALT lymphomas.

Design And Methods: Complete clinical information at presentation and during follow-up was collected for 72 patients with non-gastric MALT lymphoma treated at the Netherlands Cancer Institute between 1977 and 2005. Dissemination patterns at presentation were studied for nine primary dominant organ groups in our series of 72 patients and in a similar cohort treated at Vienna University (for a total of 106 patients).

Results: Twenty-three of our patients (32%) had more than one site of extranodal MALT lymphomatous disease, 13 patients (18%) had regional nodal involvement and 7 (10%) had bone marrow involvement. Site-specific dissemination was seen in paired organs (orbit, lung) and in the gastrointestinal tract (stomach, colon) and primary pulmonary MALT lymphoma was specifically related to gastric involvement (p<0.0001). These patterns of dissemination were retained during relapsed disease.

Conclusions: Primary extranodal non-gastric marginal zone MALT lymphoma frequently presents as stage IV disease (26%) and multifocal disease (32%) and with a site-specific dissemination pattern. After an extensive staging procedure at presentation, we recommend primary site-directed protocols during follow-up focused on the primary involved tract/organ system, regional lymph nodes and pulmonary and gastric relapses.