We described the first case on record of THRLBCL with phasic presentations of extranodal T-lymphoid hyperplasia. Although lymphoproliferative disorders and malignant lymphomas are well-recognized comorbidities in patients under immunosuppressive treatment , this case is remarkable for its presentation of contradictory benign and malignant characteristics. Whereas the metastatic features of the disease implied a malignancy, several facts such as the absence of neoplastic cells in the lesions, the blood, and the CSF, and the self-limiting invasiveness seemed to favor a benign interpretation, raising the issue of whether this disorder could correctly be classified as a single nosological entity.