Aims: To elucidate the clinicopathological features and prognostic factors of primary intestinal diffuse large B-cell lymphoma (PI-DLBL).
Methods and results: Archival tissues from 30 tumours were used for tissue microarray construction, immunohistochemistry and interphase fluorescence in situ hybridization for chromosomal translocation. The M:F ratio was 1.7:1, with a median age of 60 years. The ileum and ileocaecum were most frequently involved (40% each). Fourteen (47%) were at stage I(E) disease, 15 (50%) at stage II(E). Five (17%) tumours were perforated at presentation. The tumours expressed Bcl-6 (73%), MUM1 (70%), Bcl-2 (67%) and CD10 (23%). Nine (30%) were classified as germinal centre B-cell (GCB) phenotype and 21 non-GCB. Eight of 30 (27%), 7/30 (23%) and 2/29 (7%) cases were positive for rearrangements involving IGH, BCL6, and C-MYC loci, respectively, whereas all cases were negative for BCL2 and CCND1 translocation. Perforation was a poor prognostic indicator, with a hazard ratio of tumour-related death at 8.75 (P = 0.001). The differentiation antigens, GCB versus non-GCB phenotype, or lymphoma-associated translocations were of no prognostic significance.
Conclusions: We found a higher rate of perforation and lower frequency of GCB phenotype in PI-DLBL in Taiwan compared with other geographical areas; perforation is a poor prognostic indicator.