Importance of extensive staging in patients with mucosa-associated lymphoid tissue (MALT)-type lymphoma

Lymphoma of the mucosa-associated lymphoid tissue (MALT) type usually arise s in MALT acquired through chronic antigenic stimulation triggered by persi stent infection and/or autoimmune processes. Due to specific ligand-recepto r interactions between lymphoid cells and high-endothelial venules of MALT, both normal and neoplastic lymphoid cells display a pronounced homing tend ency to MALT throughout the body. In the case of neoplastic disease these h oming properties may be responsible for lymphoma dissemination among variou s MALT-sites. According to this concept, we have standardized staging proce dures in all patients diagnosed with MALT-type lymphoma. All patients with MALT-type lymphoma underwent standardized staging procedures before treatme nt. Staging included ophthalmologic examination, otolaryngologic investigat ion, gastroscopy with multiple biopsies, endosonography of the upper gastro intestinal tract, enteroclysis, colonoscopy, computed tomography of thorax and abdomen and bone marrow biopsy. Biopsy was performed in all lesions sug gestive for lymphomatous involvement, and evaluation of all biopsy specimen s was performed by a reference pathologist. 35 consecutive patients with hi stologically verified MALT-type lymphoma were admitted to our department. T wenty-four patients (68%) had primary involvement of the stomach, five (15% ) had lymphoma of the ocular adnexa, three (8.5%) had lymphoma of the parot id, and three (8,5%) of the lung. Lymphnode involvement corresponding to st age EII disease was found in 13 patients (37%), only one patient with prima ry gastric lymphoma had local and supradiaphragmatic lymph-node involvement (stage Bill). Bone marrow biopsies were negative in all patients. Overall, eight of 35 patients (23%) had simultaneous biopsy-proven involvement of t wo MALT-sites: one patient each had lymphoma of parotid and lacrimal gland, conjunctiva and hypopharynx, conjunctiva and skin, lacrimal gland and lung , stomach and colon, and stomach and lung. The remaining two patients had b ilateral parotideal lymphoma. Staging work-up was negative for lymph-node i nvolvement in all of these eight patients, The importance of extensive stag ing in MALT-type lymphoma is emphasized by the demonstration of multiorgan involvement in almost a quarter of patients. In addition, our data suggest that extra-gastrointestinal MALT-type lymphoma more frequently occurs simul taneously at different anatomic sites than MALT-type lymphoma involving the GI-tract. (C) 2000 Cancer Research Campaign.