In a patient treated for acute myeloblastic leukemia (AML), we saw an angiocentric and angiodestructive lymphoma that resembled lymphomatoid granulomatosis (LG). The lesions tended to involve extranodal sites such as the lung, the parotid gland, and the skin. The immunologic studies showed that the proliferating lymphoid cells were mature T cells. Furthermore, genotypic studies disclosed a clonal rearrangement of the beta T-cell receptor gene. It is concluded that this case of LG is related to a neoplastic T-cell lymphoproliferative disorder. The relations between LG and the previous AML are discussed.