Trichilemmoma. Benign follicular tumor or viral wart?

Abstract

Trichilemmoma is a follicular tumor because of its resemblance to follicular outer root sheath, overlapping features with other tumors in the spectrum of benign follicular neoplasms, occurrence as multiple dominantly inherited and solitary noninheritable tumors, and occasional complication of organoid nevus. The dangerous misinterpretation that trichilemmomas are viral warts, unsupported by scientific evidence, has harmed patients. All electron-microscopic, immunologic, and clinical transmission attempts to demonstrate viral etiology of trichilemmoma have failed. If trichilemmomas were simply old warts, we might expect to see them frequently in children, extrafacially, of long duration, associated with multiple authentic ("young") warts, as multiple lesions, and associated with authentic warts in patients with Cowden's syndrome (multiple trichilemmomas). Actually, trichilemmomas are rarely seen in children, extrafacially, of long duration, associated with multiple authentic warts, as multiple lesions in patients without Cowden's syndrome, and associated with authentic warts in Cowden's syndrome. Unfortunately, patients with multiple trichilemmomas, Cowden's syndrome, and associated internal disease have been passed off as "simply old viral warts." The missed opportunity to identify women with a 50% risk of breast cancer is a disservice to the patient, to say nothing about malpractice implications for the physician when generally accepted medical standards are not applied.