Neurofibromatosis type 1

Definition of neurofibromatosis type 1
National Cancer Institute

neurofibromatosis type 1

(NOOR-oh-FY-broh-muh-TOH-sis ...)
A rare genetic condition that causes brown spots and tumors on the skin, freckling in skin areas not exposed to the sun, tumors on the nerves, and developmental changes in the nervous system, muscles, bone, and skin. Also called NF1.

Source: NCI Dictionary of Cancer Terms