Primary extranodal non-Hodgkin’s lymphoma (NHL): the impact of alternative definitions tested in the Comprehensive Cancer Centre West population-based NHL registry

Abstract

This study illustrates the selection bias that is introduced when a strict definition of primary extranodal NHL, that excludes cases with disseminated disease, is used. Patients with primary extranodal NHL were found to have a superior DFS, irrespective of which definition of primary extranodal NHL was used.

Extranodal and splenic small B-cell lymphoma

“…[1][2][3] Involvement of extranodal sites and the spleen by lymphoma is not an uncommon occurrence. A proportion of these cases will be secondary involvement by disseminated nodal lymphoma and all nodal small B-cell lymphomas have the potential to involve extranodal sites or the spleen.…”

Primary multifocal extranodal lymphoma of the kidneys, ovaries and bones: utility of FDG PET/CT

“…Extranodal involvement in the NHL is common with primary extranodal lymphoma accounting for approximately one third of the NHL cases [1,2]. Extranodal lymphoma can occur in any organ, and can be multifocal involving two or more organs.…”

“…Extranodal lymphoma can occur in any organ, and can be multifocal involving two or more organs. The most common site of primary extranodal lymphoma is the gastrointestinal tract; the other common sites include the skin, central nervous system and testis [2][3][4]. Kidneys and ovaries are relatively uncommon sites of primary extranodal lymphoma [2][3][4].…”

Diffuse large B‐cell lymphoma

“…6,[8][9][10][11][12] Although it is relatively rare in Western countries, 6,8,12 Waldeyer ring is the commonly involved site of lymphoma in Asia and Mexico and accounts for 25% of all NHL cases in China. [9][10][11][12][13] In contrast to primary nasal lymphomas, which are predominantly of the natural killer (NK)/T-cell type, [14][15][16] NHL of Waldeyer ring is mainly of the DLBCL (WR-DLBCL) type. [8][9][10]15 Despite the early recognition of this entity, most series have reported WR-DLBCL with other types of NHL or with other lymph node or extranodal NHL sites.…”

“…[8][9][10]15 Despite the early recognition of this entity, most series have reported WR-DLBCL with other types of NHL or with other lymph node or extranodal NHL sites. [5][6][7][8][9][10]12,15 To date, few studies have focused on the similarities and differences in biologic and clinical behaviors among WR-DLBCL, lymph node DLBCL (N-DLBCL), and other extranodal DLBCLs. 6,8 The clinical features and prognosis of patients who have WR-DLBCL, and particularly its correlation with primary N-DLBCL, remain largely unknown.…”