Mycosis fungoides Overview Mycosis fungoides is a rare type of lymphoma that mainly affects the skin. Lymphoma is a cancer that begins in the lymphocytes, which are a type of white blood cell. The white blood cells are part of the body's germ-fighting immune system. There are many types of lymphoma. These types are often divided into two categories: Hodgkin lymphoma and non-Hodgkin lymphoma. Mycosis fungoides is a type of non-Hodgkin lymphoma. Mycosis fungoides got its name from the appearance of some of its skin growths, which may look like mushrooms. Mycosis fungoides got its name from the mushroom like look of some of its skin growths. It is not caused by a fungus. It begins in white blood cells called T cells, also called T lymphocytes. The T cells undergo changes and turn into cancer cells. In mycosis fungoides, the T cells attack the skin. Mycosis fungoides is one of a few types of lymphoma that affect T cells in the skin, called cutaneous T-cell lymphomas. Mycosis fungoides ...