Gastrointestinal non-Hodgkin's lymphoma. A population-based clinicopathological study of 111 adult cases with a follow-up of 10-15 years.

All cases of gastrointestinal (GI) non-Hodgkin's lymphoma diagnosed in Finland between 1972 and 1977 were histologically reexamined and immunostained in order to study the value of histological classification. One hundred and eleven cases were found. The crude annual incidence was 0.51/10(5) and the age-adjusted (world standard population) incidence 0.23/10(5). The male-to-female ratio of age-adjusted incidence rates was 2.7. The most common histological type was large B-cell lymphoma comprising 61% of all classifiable cases. Low-grade mucosa-associated lymphoid tissue (MALT) lymphoma comprised 12%, centrocytic lymphoma 9%, peripheral T-cell lymphoma 9%, Burkitt's lymphoma 7% and large-cell anaplastic lymphoma 3% of the total. In the jejunum, almost one half of the cases were T-cell lymphomas and there were no lymphomas with definite MALT features. Gastric lymphomas had higher survival rates than intestinal lymphomas, B-cell lymphomas slightly higher survival rates than T-cell lymphomas, and low-grade MALT lymphomas higher survival rates than other B-cell lymphomas. The other types of lymphomas differed only slightly from each other in prognosis. The histological grade according to the Working Formulation correlated with survival rates, but a great majority of cases were classified as intermediate grade. Classification of GI lymphomas into the types mentioned above appears to correlate with several clinical and pathological parameters.