Superficial spreading-type mucosa-associated lymphoid tissue (MALT) lymphoma in the stomach--a case report

We presented a case of a 71-year-old woman who presented irregular mucosal folds with tiny depressions and multiple erosions with ulceration in the stomach, on endoscopy and roentgenography. Histological findings from biopsy specimens showed dense and mildly atypical lymphoid-like cells invading the submucosa. Immunohistochemical examinations revealed monoclonal reactivity of Heavy-chain. She was then diagnosed to have low grade malignant lymphoma in the stomach and underwent total gastrectomy. The resected cancer demonstrated the pathological features including small lymphocytic plasmacytoid cells and lymphoepithelial lesions characteristic of a mucosa-associated lymphoid tissue (MALT) lymphoma. The lymphoma cells expressed B cell markers with a phenotype of IgG and lambda type. It is difficult to make a firm diagnosis of a MALT lymphoma from only small biopsy specimens. Accordingly it is necessary to complete the observed clinical process, endoscopic and roentgenographic findings with immunohistochemical characteristics to determine diagnosis. The MALT lymphoma should be treated as a low-grade malignancy and diagnosis sufficiently early can lead to a favorable prognosis.