Most primary intestinal natural killer (NK)-cell and T-cell lymphomas (PINKTL) in the Northern Europe are enteropathy-associated T-cell lymphomas, a complication of celiac disease, which is rare in the East. Primary intestinal NK-cell lymphoma is extremely rare and is poorly characterized. We investigated 30 cases of PINKTL from Taiwan with male: female at 2:1, median age at 55.5, 80% with jejunal/ileal involvement, 77% with perforation, 27% with multicentric tumors, and 67% at stage IE. All 7 cases tested for serum IgA anti-tissue transglutaminase were negative. Only 3 (10%) tumors showed enteropathy. Six (20%) were NK-cell lymphoma and 24 (80%) were T-cell lymphoma. The tumor cells in 21/30 (70%) cases were small to medium sized, which correlated with the coexpression of both CD8 and CD56. All tumors expressed at least 1 cytotoxic marker. All 6 NK-cell lymphomas were negative for betaF1, diffusely positive for Epstein-Barr virus-encoded mRNA (EBER), and polyclonal for T-cell receptor gene rearrangement. Five (22%) of the 24 T-cell tumors expressed betaF1, 8 (35%) of the 23 tumors were positive for EBER, and 20 (95%) of the 21 tumors were clonal for T-cell receptor. The overall 1-year survival was 36%. Univariate regression analysis showed that NK-cell lineage, multicentricity, and perforation were associated with poor prognosis. NK-cell lineage (P=0.037) was a poor prognostic factor by multivariate Cox proportional hazard regression analysis. PINKTL in Taiwan is predominantly not enteropathic with a high frequency of perforation, small to medium tumor cell size and cytotoxic phenotype. Primary intestinal NK-cell lymphoma carries a very poor prognosis, and is probably a distinct entity.

Multiple myeloma (MM) is rarely associated with Epstein-Barr virus (EBV) irrespective of HIV status, in contrast with its morphologic mimic, plasmablastic lymphoma, which occurs mainly in immunocompromised patients with frequent EBV association. Among 58 consecutive immunocompetent patients, we found plasmablastic cytomorphologic features in 2 of 4 with plasmacytomas and 14 (26%) of 54 with MM. Of the tumors, 4 (7%; 1 plasmacytoma and 3 MMs) were EBV-encoded RNA (EBER)-positive with plasmablastic cytomorphologic features in 3. The patient with plasmacytoma was disease free for 75 months, and the remaining 3 patients with MM died at 15, 74, and 97 months, respectively; the median survival of patients with EBER- MM was 12 months. EBV+ tumors were associated with plasmablastic cytomorphologic features and high labeling indices. Rare EBER+ plasmablastic plasma cell tumors exist in immunocompetent patients. These tumors may have been driven by EBV to gain the plasmablastic cytomorphologic features and high proliferation fraction. A large cohort study is needed to clarify the prognostic impact of EBV on immunocompetent patients with MM.

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Cyclin D1-positive DLBCLs are rare, and they are negative for SOX11 or CCND1 aberration. SOX11 is useful in differentiating cyclin D1-positive DLBCL from MCL.

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.