Cutaneous intravascular NK/T-cell lymphoma with peculiar immunophenotype.

Abstract Intravascular lymphoma (IVL) is a rare entity. Most cases are a variant of extranodal diffuse large B-cell lymphoma, and fewer than 10% of the published cases are of T-cell origin. Only intravascular B-cell lymphoma is recognized as a distinct entity in the most recent WHO classification of lymphoproliferative disorders. We describe a case of cutaneous NK/T IVL, with a cytotoxic immunophenotype and EBV positivity. However, our case was immunohistochemically negative not only for TCR-βF1 and TCR-γ (TCR-silent), but also for CD56, making it the first triple-negative NK/T IVL case to be described. We urge the recognition of this NK/T-cell lineage intravascular lymphoma due to its particular immunophenotypic profile and its unvarying relationship with EBV. Its occurrence should not be considered a coincidence, but rather a key aspect of the pathogenic background of this haematological neoplasm. This article is protected by copyright. All rights reserved.