Background: The concept of mucosa-associated lymphoid tissue (MALT) lymphoma is now widely accepted. However, precise characterization of the features of MALT lesions in the stomach is needed. For this, extensive analysis of resected gastrectomy specimens from a large number of patients with MALT lymphoma is essential.
Methods: Fifty-three patients who underwent gastrectomy for the treatment of primary gastric lymphoma were studied. In the histologic examination, a mean of 46 specimens per case were analyzed; the distribution of lymphomatous lesions was plotted on maps of gastrectomy specimens, input into a computer, and used to measure the size of lesions.
Results: The median age of the patients was 56 years, and the male-to-female ratio was 27:26. Stage of disease was I(E) for 35 patients, II(E) for 15, and III for 3. Histologically, 25 patients had low grade lesions, 18 had combined high and low grade lesions, and had 10 high grade lesions. Macroscopically, low grade MALT usually had multiple instances of superficial spreading of lesions without ulceration, whereas high grade MALT exhibited a solitary tumor-forming lesion. All of the superficial spreading type without ulceration were low grade MALT. The higher the grade of tumor, the larger the tumor size. Twenty-four patients received chemotherapy. The 5-year survival rate was 67.2%. Multivariate analysis revealed that only the clinical stage was a significant factor in prognosis.
Conclusions: Low grade MALT can be differentiated from other types of MALT by macroscopic findings. When the MALT concept is adopted, stage of disease is important in relation to survival.