Primary extranodal non-Hodgkin's lymphoma in adults: clinicopathological and survival characteristics.

Among 318 cases of non-Hodgkin's lymphoma (NHL) treated in our unit, 145 (45.6%) had primary extranodal NHL (PE-NHL). The stomach was the most common site (42.1%), followed by the PE-NHL of the head and neck region. Histologically aggressive histologies (65.5% intermediate and 20.7% high grade) predominated. 89.6% of the cases were localized (stage IE, 51% and stage II, 38.6%) but 28% had B symptoms. CR was achieved in 82.1% of the cases. 5-years disease free survival and overall survival were both 65%. Factors that influence prognosis were stage and high grade histology. Among various primary sites the Waldeyer's ring, small intestine and testes had the worse prognosis. Compared to nodal NHL, the PE-NHL were more frequently localized, belonged more often to aggressive histologies and had more often distal extranodal relapses. CR rates and disease free and overall survival were significantly better for PE-NHL. The survival rates, however, listed according to stage and histology for nodal and PE-NHL were not different. We conclude that although PE-NHL differed from nodal NHL in several respects, prognosis is mainly a factor of stage and histology rather than of the primary localization per se.