ABSTRACT
Cutaneous lymphomas include B- and T-cell lymphomas, both primary (with involvement of the skin being a main clinical feature) and systemic. T-cell lymphomas comprise the majority of primary cutaneous lymphomas. The current WHO classification (2016), based on prior WHO/EORT classification divides them into numerous categories, reflecting their morphologic, immunophenotypic, genetic, and clinical heterogeneity [1–3]. The prognosis of cutaneous T-cell lymphomas varies from indolent (e.g., mycosis fungoides [MF], lymphomatoid papulosis [LyP], CD4+ small/medium-sized pleomorphic T-cell lymphoproliferative disorder, primary cutaneous marginal zone lymphoma [MZL] [PCMZL], and primary cutaneous follicle center lymphoma [PCFCL]) to aggressive (e.g., primary cutaneous diffuse large B-cell lymphoma [DLBCL], Sezary syndrome [SS], extranodal NK-/T-cell lymphoma [ENKTL], nasal type, cutaneous γδ T-cell lymphoma [CGD-TCL], and aggressive epidermotropic CD8+ T-cell lymphoma). Many of primary cutaneous lymphomas have a predilection to specific body region, and therefore, location of the tumor often helps in the differential diagnosis (Figure 48.1).
