Abstract： An unusual case of primary cutaneous anaplastic large cell lymphoma induced by influenza vaccination is reported.A 79-year-old man developed an erythematous nodule at the injection site on the upper left arm 2 months after vaccination against influenza A virus,which gradually grew and ulcerated.Pathological examination of the lesion revealed epidermal infiltrate of lymphocytes and numerous clumps of densely distributed lymphocytes with lightly stained cytoplasm,nuclear atypia and karyokinesis.Immunohistochemistry showed that the tumor cells stained positive for CD3 (90％),CD5 (90％),LCA (90％),CD30 (90％),CD10 (a few),Ki-67 (80％),but negative for CD20,CD56,cytokeratin 1-3,epithelial membrane antigen,synaptophysin,and anaplastic lymphoma kinase.The patient was diagnosed with primary cutaneous anaplastic large cell lymphoma at the injection site following vaccination against influenza A virus.