Update on cutaneous lymphomas

Cutaneous lymphomas (CL) are heterogeneous and grouped in a common WHO classification last updated in 2016. The most recent and significant insights in this group include: 1) the identification of the primary cutaneous (PC) Primary cutaneous CD8+ acral T-cell lymphoma and the muco-cutaneous ulcer as new entities, 2) The integration of PC diffuse large B-cell lymphoma-leg type as a discreet entity, 3) the delineation of the indolent and localized PC CD4+ small medium T-cell lymphoproliferative disorder (LPD), 4), the identification of new phenotypic and molecular variants of PC CD30+ LPD, including the cytotoxic type D and E and those with a DUSP22 rearrangement, 5) the description of hot spot mutations of interest for diagnostic purposes in DLBCL-LT (MYD88 L265P) and skin localizations of angio-immunoblastic T-cell lymphomas (RHOA G17V and IDH2 R172K/S), and finally 6) the description of new features of well-known CL, some of which may pave the way for new therapies, such as KIR3DL2 targeting.