A 38 year old man died suddenly of widespread lymphoid neoplasm after a short clinical course. Histologically the tumor was composed of pleomorphic large cells that often demonstrated phagocytic activity. Moreover, histochemical and immunohistochemical tests revealed that the tumor cells had the phenotypes of both anaplastic large cell lymphoma and histiocytic cells. Immunogenotyping failed to demonstrate any lymphoid nature. This case might be categorized as anaplastic large cell lymphoma with histiocytic phenotypes.