OBJECTIVETo investigate the clinicopathological and immunohistochemical features of lymphoblastic lymphoma (LBL).

METHODSA retrospective clinicopathological study of 96 cases LBL was carried out. Immunohistochemical staining was used for the characterization and immunophenotyping.

RESULTSThe patients age ranged from 4 to 72 years, with a median of 16 years, 69 patients were male and 27 female. Seventy-three cases had superficial or multi-lymphoadenopathy and 31 of them had mediastinal masses. Bone marrow was involved in 15 cases. Seventy-three cases were in clinical stages III and IV. The median survival of the followed-up patients was 5.5 (2 approximately 120) months. TdT and CD99 positive reactions were 75.0% and 92.7%, respectively. Of the 96 cases, 78 displayed T-cell marker positivity and 18 B-cell markers. 82.1% of the patients younger than 30 years of age had significantly higher incidences of T-LBL (64 patients), and 93.6% of the patients with mediastinal masses expressed T-cell markers. The poor prognostic factors were T-cell tumors, clinical stages III and IV, Ki-67 PI < 80% and no chemotherapy (P < 0.01).

CONCLUSIONIn children and young males, mediastinal masses with superficial or multi-lymphoadenopathy favors the diagnosis of LBL, but negative TdT reaction can not exclude this diagnosis. T-LBL is more common than B-LBL. Clinical stages, immunophenotypes and the level of Ki-67 expression were closely related with prognosis of LBL.