Primary adrenal lymphoma is extremely rare, accounting for o1% of non-Hodgkin lymphomas, and lymphomaassociated chromosomal translocations have yet to be reported in this entity. We performed a retrospective study of 10 cases in immunocompetent patients including 4 males and 6 females with a median age of 68 years. The most common presenting symptoms were abdominal pain and fever; unexpectedly, clinically evident adrenal insufficiency was detected only in one patient. The mean tumor size at diagnosis was 8.5 cm. Half of the patients had bilateral involvement. All cases presented with stage IE disease without regional nodal involvement. Histologically, eight cases were diffuse large B-cell lymphoma, all of which carried a nongerminal center B-cell phenotype. Fluorescence in situ hybridization revealed BCL6 gene rearrangement in 5 (83%) of 6 diffuse large B-cell lymphomas investigated. The remaining cases were one case each of plasmablastic lymphoma and extranodal NK/T-cell lymphoma, nasal type, the first and third case of primary adrenal lymphoma of these particular lymphoma subtypes in the English literature, respectively. At a median follow-up of 4.5 months, 7 patients died of lymphoma, 1 died of an unrelated disease, 1 was alive with disease, and 1 was alive without disease. The prognosis of these patients was poor as compared with those with nodal diffuse large B-cell lymphoma. We speculate that the poor outcome of primary adrenal lymphoma might be related to the bulky tumor size at presentation, non-germinal center B-cell phenotype, and frequent BCL-6 gene rearrangement. Keywords: adrenal insufficiency; diffuse large B-cell lymphoma; NK/T-cell lymphoma; plasmablastic lymphoma; primary adrenal lymphoma; Taiwan Although secondary involvement of the adrenal glands by non-Hodgkin's lymphoma is not uncommon, primary adrenal lymphoma is extremely rare and accounts for o1% of all non-Hodgkin's lymphoma cases. 1 In the English literature, most of the papers on primary adrenal lymphomas are singlecase reports and literature reviews based on a small number of cases except two large series. [1][2][3][4][5] Up to half of the small number of reported patients with primary adrenal lymphoma were associated with adrenal insufficiency and there is a high rate of