title: Clinico-pathological pattern of extranodal non-Hodgkin's lymphoma in Saudi Arabia.
abstract: OBJECTIVE
  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.
authors.affiliation: The Department of Medicine, King Saud University, Saudi Arabia. ameralem@ksu.edu.sa
authors.forename: Abdul Rahman
authors.initials: AR
authors.lastname: Al Diab
authors.forename: Aamer
authors.initials: A
authors.lastname: Aleem
authors.forename: Abdul
authors.initials: A
authors.lastname: Qayum
authors.forename: Ahmed S
authors.initials: AS
authors.lastname: Al Askar
authors.forename: Dahish S
authors.initials: DS
authors.lastname: Ajarim
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000453:epidemiology / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D005770:Gastrointestinal Neoplasms / Q000453:epidemiology / Q000473:pathology*; D006258:Head and Neck Neoplasms / Q000453:epidemiology / Q000473:pathology*; D006801:Humans; D015994:Incidence; D016403:Lymphoma, Large B-Cell, Diffuse / Q000453:epidemiology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D012529:Saudi Arabia / Q000453:epidemiology; D012878:Skin Neoplasms / Q000453:epidemiology / Q000473:pathology*