Stomach lymphomas: minimum diagnostic requirements for gastrointestinal histopathological diagnosis

Gastric lymphomas have been the subject of intensive studies in the last years and important progress has been made regarding their etiopathogenesis and therapy. Diagnosis of gastric lymphoma is usually made on bioptic material taken at endoscopy. Histopathologic diagnosis is frequently difficult. This paper summarizes the main diagnostic criteria of this setting. It analyses the morphological, immunohistochemical and molecular features to be considered for the differential diagnosis between: reactive process vs low grade B-cell gastric MALT lymphoma, B-cell MALT lymphoma vs other low grade lymphomas involving the stomach and low grade vs high grade gastric lymphoma. The histopathological aspects of gastric biopsies after antibiotic treatment for Helicobacter pylori eradication and the role of molecular analysis in the follow-up of these patients are also considered.