This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Proliferating trichilemmal tumor (PTT) is a benign tumor originating from the hair follicle. Although it is a benign tumor, PTT may be locally aggressive and in very rare cases the tumor may become malignant. In most cases there is only one lesion and occur in elderly women. The tumor is not painful but sometimes they may grow very large and pressure and damage the skin around it resulting in wounds and foul-smelling discharge. About 90% of the cases are on the scalp, but they have also been found on the forehead, nose, back, chest, abdomen, buttocks, elbow, wrist and genitalia. Treatment is with surgery removing the lesion. Prognosis is good in most cases but the patient should be followed closely after surgery.
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