Abstract: | Lymphoblastic lymphomas (LBLs) are uncommon malignant neoplasms derived from immature T‐ or B‐lymphoid progenitor cells. Although cutaneous involvement may reach 33% in B‐LBL, only 12 cutaneous cases of T‐LBL have been published. We report the case of a 49‐year‐old woman with 2‐month history of erythematous‐violaceous plaques in the sternal region and breasts. Histopathologic examination showed a dense monomorphus infiltrate in dermis and positive immunostainings for CD3, CD99 and terminal deoxynucleotidyl transferase, thus indicating T‐LBL. Staging work‐up only revealed a mediastinal mass at diagnosis. After a 51‐month follow‐up and different treatment regimens, the patient remains alive although she has presented four relapses, all of them extramedullary. |