Abstract: Objective To report a rare case of T-lymphoblastic lymphoma with erythema annulare as an initial manifestation.Methods The clinical、histopathologic、immunohistochemical、molecular biological and several special laboratory examinations of the disease were evaluated.Results Numerous enlarged lymph nodes were found in both neck and inguinal region.More than one hundred annular lesions were found all over the body.CT of chest showed the anterior superior mediastinum was occupied by lymphoma.Atypical cells were found in pleural fluid.The bone marrow smear showed the involvement of lymphoma.Notumor cells were found in the peripheral blood.The histopathologic examination of lymph nodes showed the structure of lymph nodes was destructed and tumor cells diffusely infiltrated,manifesting as "starry sky" appearance,with convoluted nuclei in some tumor cells.The tumor cells were of T-lineage[CD43⁺,leukocyte-common antigen(LCA)⁺,UCHL-l(CD45RO)⁺] and lymphoblast(terminal deoxynucleotidyl transferase,TdT⁺).The pathologic examination of skin lesions(erythema annulare)showed band-like lymphoid cell infitration in superficial dermis.Some lymphoid cells showed epidermotropism and Pautrier microabscess was also found.Convoluted nucleus was observed in a few lymphoid cells which was similar to the tumor cells in the lymph nodes.The lymphoid cells of the skin lesions were of T-lineage(CD43⁺,LCA⁺,UCHL-l⁺,TdT^-).Epstein-Barr virus encoded RNA(EBER)l/2 was positive in involved lymph nodes,but negative in skin lesions,by in situ hybridization(HIS-RNA)technique.Conclusion This is the first case reported in China that erythema annulare is the initial manifestation of T-lymphoblastic lymphoma.

Key words: Lymphoma, lymphoblastic, Erythema