Coincidence of de novo T-lymphoblastic lymphoma and cutaneous gamma/delta peripheral T-cell lymphoma

The coincidence of acute T-lymphoblastic leukemia/lymphoma, NOS (T-ALL/LBL), and peripheral T-cell lymphoma (PTCL) is unusual, and there have only been a few cases of their metachronous occurrence. In these cases, PTCLs emerged as recurrence after primary therapy for primary T-ALL, were the rare gamma/delta type, and uncommonly involved skin for T-ALL/LBL. We herein report the first case of de novo T-LBL that coincided with cutaneous gamma/delta PTCL before primary therapy. A 70-year-old man presented with systemic lymphadenopathy. Lymph node biopsy revealed a massive proliferation of lymphoblastoid cells; immunohistochemically, they were positive for TdT/CD1a/CD99, and cytoplasmic CD3 epsilon, CD4, and CD8 and were negative for T-cell receptor (TCR) beta f-1. A few TCR delta-positive cells were intermingled. Atypically, TIA was focally positive, whereas granzyme/perforin was negative. Multiple papules and plaques emerged on the trunk before the initiation of treatment for T-LBL. Skin biopsy revealed a massive proliferation of medium-to-large atypical lymphoid cells that were TdT/ CD1a-negative mature T-cells; they were negative for TCR beta f1 and CD4, and positive for TCR delta, CD5, CD8, CD56, TIA, granzyme B, and perforin. A conventional PCR analysis of TCRG showed no identical clonal band between the two tumors. The skin lesion was diagnosed as cutaneous gamma/delta T-cell lymphoma. Whether the lesion was primary or a transformation of T-LBL was unclear. After treating with reduced hyper-CVAD/MA targeting T-LBL, molecular complete remission was achieved. When an uncommon cutaneous lesion emerges in the course of T-ALL/LBL, both need to be evaluated pathologically and genetically, whether de novo or recurrent, assuming the possibility of coincident gamma/delta PTCL.