OBJECTIVETo evaluate the epidermiology, clinicopathological features and prognosis of primary extra-nodal non-Hodgkin's lymphoma (PE-NHL).

METHODSThe clinicopathological data of 151 patients diagnosed as PE-NHL in the First Affiliated Hospital of Jilin University between January 2007 and December 2011 were reviewed and analyzed.

RESULTSThe proportion of PE-NHL patients was 58.8% among all the non-Hodgkin's lymphoma cases, with the average age of 52 years, and the male/female ratio was 1.16:1. The most frequently involved site was the stomach (30.5%) followed by nose and sinuses (19.9%) and Waldeyer's ring (17.2%). The most common subtype was diffuse large B-cell lymphoma (DLBCL) (55.0%), followed by NK/T (18.5%) and extra-nodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) ( 13.2%). The distribution of clinical stages was as follows: stage I 20.5%, II 29.8%, III 29.1%, and IV 20.5%. Most nasal PE-NHL is in early stages, with a proportion of 76.7% in stages I & II. The 3-year overall survival rate was 73.2% and 3-year progression free survival rate was 46.6% in the PE-DLBCL patients. The International Prognosis Index (IPI) could be used to estimate the prognosis of PE-DLBCL well. Multivariate analysis showed that ESR and curative effect of the first treatment were independent prognostic factors for PE-DLBCL patients.

CONCLUSIONSThe incidence of PE-NHL is quite high, and the most common primary extra-nodal site is the gastro-intestinal tract and the most common subtype is diffuse large B-cell lymphoma. Risk groups based on IPI can indicate the prognosis of PE-DLBCL to some extent, but only the ESR and curative effect of the first treatment are confirmed to be independent risk factors.