Box 1 WHO—EORTC classification of primary cutaneous lymphomas.

Cutaneous T cell and NK cell lymphomas

Mycosis fungoides

MF variants and subtypes

Folliculotropic MF

Pagetoid reticulosis

Granulomatous slack skin

Sézary syndrome

Adult T cell leukaemia/lymphoma

Primary cutaneous CD30 lymphoproliferative disorders

Primary cutaneous anaplastic large‐cell lymphoma

Lymphomatoid papulosis

Subcutaneous panniculitis‐like T cell lymphoma

Extranodal NK/T cell lymphoma, nasal type

Primary cutaneous peripheral T cell lymphoma, unspecified

Primary cutaneous aggressive epidermotropic CD8 T cell lymphoma (provisional)

Cutaneous γ/δ T cell lymphoma (provisional)

Primary cutaneous CD4 small/medium‐sized pleomorphic T cell lymphoma (provisional)

Cutaneous B cell lymphomas

Primary cutaneous marginal zone B cell lymphoma

Primary cutaneous follicle centre lymphoma

Primary cutaneous diffuse large B cell lymphoma, leg type

Primary cutaneous diffuse large B cell lymphoma, other

Intravascular large B cell lymphoma

Precursor haematological neoplasm

CD4/CD56 haematodermic neoplasm (blastic NK cell lymphoma)

MF, mycosis fungoides; NK, natural killer; WHO–EORTC, World Health Organization–European Organization for Research and Treatment Classification.