Epidermodysplasia verruciformis: Description, Causes and Risk Factors:
A rare inherited disease with numerous flat warts on the hands and feet, in patients with inherited defects in cell-mediated immunity and increased susceptibility to HPV (human papillomavirus) infections; skin carcinoma sometimes develops. There is a genetic component in the etiology, but the inheritance pattern is uncertain at present.
The pathophysiology of epidermodysplasia verruciformis (EV) is linked to defective cell-mediated immunity with elucidation of mutations in EVER1 and EVER2 genes (band 17q25). In addition, a profound CD8+ T-cell lymphocytopenia was identified.
The exact mechanisms involved in the malignant transformation of keratinocytes in skin lesions of patients with EV are still unclear. The persistence of HPV infection in EV is thought to be the result of an immunogenetic defect, which generates several cytokines capable of down-regulating cell-mediated immunity. There are at least 20 HPV types characteristic of EV including types 3, 5, 8, 9, 10, 12, 14, 15, 17, 19-25, 28, 29, 36, 38, 47, and 50.
Although EV is most commonly inherited in an autosomal recessive manner, sporadic, sex-linked, and autosomal dominant inheritance have been described. The disease is characterized by chronic infection with HPV. Widespread skin eruptions of flat-to-papillomatous, wart like lesions and reddish-brown pigmented plaques on the trunk, the hands, the upper and lower extremities, and the face are typical.
Epidermodysplasia verruciformis has been addressed in depth in the recent literature despite its rarity. The disease is characterized by a persistence in HPV infections and development of cutaneous malignancies, usually happening more frequently and at a younger age than in the general population. Because of the role of immunodeficiency to viral antigens eventually leading to cancer, EV has become a model for understanding a viral role in cutaneous oncogenesis. Susceptibility loci for EV have been mapped and encoded protein functions are becoming better understood. Discoveries of novel mutations and further study of EV-associated HPV serotypes in lesional and non-lesional skin of affected patients and the general population may help generate a cohesive theory regarding the true role of a defective immune barrier in oncogenesis.
EV usually begins in infancy or early childhood, with the development of various types of flat, wart-like lesions and confluent plaques on the skin, especially on dorsal hands, extremities, face, and neck. Patients may also develop tinea versicolor-like lesions on the trunk. EV lesions may progress to form verrucous plaques and nodules
, or they may transform into invasive squamous cell carcinomas, most commonly between the ages of 20 and 40 years.The clinical course of epidermodysplasia verruciformis is protracted.
Most cases of EV are diagnosed well before the threat of cancer
is present. Doctors can make a diagnosis by performing thorough physical exams and testing blood and skin samples for the presence of HPV. Genetic testing confirms that certain genes carry the characteristic mutations that cause EV.
No therapy for EV is definitive. Treatment of EV includes preventive measures, the most important of which is strict sun avoidance and protection, beginning as soon as the diagnosis is made. Surgical and electrosurgical removal and cryotherapy are used in the treatment of benign and pre-malignant skin lesions.
The role of etretinate in EV treatment is not clear. Substantial clinical improvement is often achieved at dose of 1 mg/kg/day. The effect is dose-dependent and relapse occurs if the drug is stopped. Patient should be observed for development of carcinoma and pre-malignant lesions. Avoidance of excessive sun exposure with intelligent use of effective sunscreen should be advised.
NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.