Mycosis Fungoides

Auris Huen, MD, PharmD, Assistant Professor, MD Anderson Cancer Center, Department of Dermatology provides an overview of Mycosis Fungoides, a subtype of Cutaneous T-cell lymphoma (CTCL).

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

Many forms of CTCL are relatively indolent compared with other T-cell lymphomas, but there are aggressive subtypes. This is illustrated by the two most common forms of CTCL: mycosis fungoides and Sézary syndrome. Although mycosis fungoides is considered a slow-growing variant, Sézary syndrome is aggressive and generally has a poor prognosis. Importantly, even the indolent subtypes can progress in some patients and become difficult to manage.

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.