Clinico-pathological pattern of extranodal non-Hodgkin's lymphoma in Saudi Arabia.

Objectives: The incidence of primary extranodal non-Hodgkin's lymphoma (NHL) is variable in different regions of world but there is a paucity of literature on various demographic aspects of extranodal NHL as a group. This study was conducted to evaluate the clinico-pathological pattern of extranodal NHL in Saudi patients. Methods: We retrospectively studied a cohort of 855 NHL patients in four tertiary care centres in Riyadh, Saudi Arabia over a period of 5 years. Results: Extranodal NHL constituted 41.4% of the total. The mean age of affected patients was 55 +/- 18 years and a male to female ratio of 1.5:1.0. Most presented in the age range of 41-60 years. NHL of gastro-intestinal (GI) tract was the most common extranodal variety, followed by head and neck NHL (18%), primary cutaneous lymphoma (14.4%), primary CNS lymphoma (5.6%), and primary bone, thyroid and soft tissue lymphoma (4.5% each). In the GI tract, stomach was the most common site involved, accounting for more than 81% of GI NHL. Diffuse large B-cell lymphoma was the most common histologic type, comprising around 72% of all extranodal lymphomas. Conclusions: Extranodal NHL is common in Saudi Arabia and diffuse large B cell lymphoma is the most common histologic subtype. We found significant differences in the pattern of extranodal NHL in Saudi patients compared to those reported from other parts of the world. Further studies focused on the risk factors and treatment outcome are needed to better understand the biology of a disease common in this population.