The majority of<unk> s are non-Hodgkin's<unk>  of B-cell origin. These tumors may range from well-differentiated, superficial involvements (MALT) to high-grade, large-cell<unk> s. Sometimes, it's hard to differentiate poorly differentiated high grade B-cell<unk>  from gastric adenocarcinoma clinically or radiologically, yet histopathology with immunohistochemistry is recommended to stain specific markers on the malignant cell that favor the diagnosis of<unk> . Immunohistochemistry stains specific clusters of differentiation that are present on B-cells like CD20. Cytokeratin is also a surface marker that is presented on epithelial cells, is stained histochemically and favors the diagnosis of epithelial tumors like adenocarcinoma. Differentiating poor<unk>  from adenocarcinoma is essential because the prognosis and modalities of treatment differ significantly. Other<unk> s involving the stomach include mantle cell<unk>  and T-cell<unk> s which may be associated with enteropathy; the latter usually occur in the small bowel but have been reported in the stomach.
Gastric lymphoma
Poorly cohesive gastric carcinoma
Atrophic gastritis
Lymphocytic esophagitis
Oesophagogastric junctional adenocarcinoma
Hereditary diffuse gastric cancer
Tropical ulcer
Herpes esophagitis