MALT Lymphoma : Clinical Features

Comments:
MALT Lymphomas - Clinical Features: MALT lymphomas are indolent, low-grade B-cell tumors that mainly occur in adults at a median age of 60 years. There are site-specific sex differences in incidence, for example, salivary gland and thyroid MALT lymphomas show female predominance where as cutaneous MALT lymphoma is more common in males. There are also notable geographic differences in incidence for some subtypes of MALT lymphomas.

Patients usually present with localized disease (Stage I or II) involving epithelial tissues at specific sites. However, between 25-40% have disease at multiple extranodal sites. Bone marrow is involved in less than 20% of cases. Peripheral blood is usually not involved. Multifocal disease and bone marrow involvement is more common in non-gastric MALT lymphomas. Generalized lymphadenopathy occurs in <10% of cases. Plasmacytic differentiation is common and a serum paraprotein is detectable in one-third of patients. Site-specific clinical features are discussed with individual entities.

This low power view of a gastric MALT lymphoma shows multiple tumor nodules expanding the lamina propria and trying to recapitulate the morphology of Peyers patches.