Joan Guitart, MD, Chief of Dermatopathology in the Department of Dermatology, Professor of Dermatology (Dermatopathology) and Pathology at Northwestern University, Feinberg School of Medicine discusses two main subtypes of cutaneous Tcell lymphoma (CTCL): mycosis fungoides and sézary syndrome.

Cutaneous Tcell lymphoma belongs to the nonHodgkin lymphoma class of hematologic Tcell lymphoproliferative disorders. Cutaneous Tcell lymphoma is a rare group of malignancies, with an incidence of 6.4 cases per 1 million people. This form of Tcell lymphoma represents around 70% of primary cutaneous lymphomas.

According to the Leukemia and Lymphoma Society, seven subtypes of CTCL exist. Like many hematologic malignancies, several of these subtypes are differentiated according to molecular markers on the surface of cancerous cells. The most common subtype, mycosis fungoides, typically progresses slowly, over years. However, some cases will advance to the lymph nodes, blood, and rarely, visceral organs.

Sézary syndrome, the second most common type of CTCL, is more aggressive than mycosis fungoides. It is characterized by Sézary cells accumulation in the skin, leading to erythroderma, as well as in the blood and lymph nodes.