Erythrodermic Mycosis Fungoides Presenting with Ichthyosiform Eruptions Under Extracorporal Photopheresis

Mycosis fungoides (MF) typically manifests in three classical clinical stages (patch, plaque and tumor form) and its clinical presentation is well known for dermatologists and dermatopathologists. A great variety of morphologic variants are known and three distinct entities have been named in the WHO/EORTC classification system in 2005: folliculotropic MF, pagetoid reticulosis and granulomatous slack skin. Erythrodermic forms are known and have to be differentiated from a Sezary syndrome. Reports of an ichthyosiform MF are rare. We present the case of an erythrodermic variant of MF with development of ichthyosiform eruptions under extracorporal photopheresis. Clinical and dermatopathological aspects as well as pathogenetic hypothesis are discussed.