[Pilar tumor of the scalp. Case report and study of 59 cases]

The pilar tumor occurs mainly in elderly women. It is a solitary lesion, localized on the scalp in most cases. In spite of the usually long course of the disease, pilar tumors very rarely metastasize. Small tumors look like "sebaceous cysts", large and very large tumors are diagnosed as squamous cell carcinomas. In these cases one could directly come to the right diagnosis if sex, age and localization do correspond. Microscopic examination reveals interlacing lobules of squamous eqithelium that undergo in their center abrupt keratinization of pilar or trichilemmal cysts. The pilar tumor, therefore, keratinizes like the middle portion of the outer root sheath. Our own case shows the typical above-mentioned clinical and histological signs of the pilar tumor.