Primary non-Hodgkin's lymphoma of bone: a rare disorder with high frequency of T-cell phenotype in southern Taiwan.

Primary non-Hodgkin's lymphoma of bone (PLB) is a rare disorder representing less than 1% of all non-Hodgkin's lymphomas and has rarely been reported in Taiwan. A retrospective clinicopathological study was performed according to the 2002 World Health Organization criteria and identified 14 cases during a 13-year period in 2 medical centers in southern Taiwan. There was male predominance (M:F = 6:1) with a median age of 42 and bone pain (6 patients, 43%) as the most common symptom. Half of the patients had monostotic and the other half polyostotic lesions. Axial skeletons (10 cases, 71%) were the most frequent sites of involvement. The staging results were stage I (9 patients, 64%), stage II (2, 14%) and stage IV (3, 21%). Eight cases (57%) were of B-cell phenotype and the remaining 6 (43%), T-cell. Histologically, 7 (50%) were diffuse large B-cell lymphomas (DLBCLs) and 5 (36%) anaplastic large cell lymphomas. Seven patients received chemotherapy and radiotherapy; 4 chemotherapy and 3 radiotherapy alone. Of the 11 patients with follow-up information, 6 (55%) died of disease within 1 year including 5 with T-cell lymphomas, while all the 5 patients surviving over 1 year were of B-cell phenotype. The overall 1-year survival rate was 45%. The survival of B-cell lymphomas was significantly better than T-cell tumors (p = 0.016, log-rank test). In summary, this study reported the largest series of PBL in Taiwan and confirmed that the majority was DLBCL and B-cell tumors had more favorable prognosis. As compared to the Western series, the cases showed a striking male predominance, higher percentage of axial skeleton involvement, higher relative frequency of T-lineage tumors and poorer prognosis.