Immunohistological Study of Lymphoblastic Lymphoma

Immunological characteristics of eight cases of lymphoblastic lymphoma (LBL) were studied. When LBLs were divided into T-cell and B-cell type according to marker expression of neoplastic cells, six of eight cases displayed T-cell markers and other cases expressed B-cell markers. Based on nuclear shape, the cases were morphologically divided into convoluted (two cases) and non-convoluted type (six cases).Expression of B-cell markers in one of two cases with convoluted nucleus suggested that convoluted nucleus was not limited to T-cell type. In T-LBL, some cases expressed CALLA (J5) or HLA-DR (Ia-like antigen). In five of six cases of T-LBL, Leu-8 positive neoplastic cells were observed. In non-neoplastic thymus, Leu-8 positive cells were found in medulla and subcapsular region. Leu-8 antigen may give a clue to clarify the origin of T-LBL.