Histology of HPV

The human papilloma virus (HPV) is a virus that infects the mucous membranes and the skin. More than 100 types of the human papilloma virus exist. The histology (microscopic structure) of HPV may help determine which type of human papilloma virus is present, but not always. Ordinary warts found on the hands and feet can be caused by certain types of HPV and are spread by skin-to-skin contact. Roughly 30 types of HPV can only be spread through direct genital contact.

Types

• Each of the genital HPV types has been assigned a number in the order of their discovery, for example HPV 6. They are broken up into two different groups: low-risk and high-risk. Around 12 types of HPV are known as low-risk since they cannot cause cervical cancer in females. They do cause genital warts though, with types 6 and 11 being linked to around 90 percent of genital wart outbreaks. More than a dozen types of HPV are considered high-risk, because they may cause abnormal cell growth on the cervix. If not removed, the abnormal cells can slowly develop into cervical cancer. Roughly 70 percent of cervical cancers are caused by HPV types 16 and 18.

Identification

• According to the “Journal of Clinical Pathology,” a study that was conducted on the histology of HPV-related abnormal cell growth demonstrated that conventional histology could not distinguish between HPV type 6 (low-risk) and 16 (high-risk). Warts induced by HPV types 3, 4 and 6 did show a correlation between histology of the warts and virus type, though. The histology of HPV warts caused by types 3, 4 and 6 mainly varies with their different-shaped nuclei (cell parts responsible for growth and reproduction).

Symptoms

• Typically the first visible signs of the HPV virus are genital warts. They usually appear as a bump or group of bumps that can resemble cauliflower-type growths. The warts can be large or small and flat or raised. Genital warts can be found on the inside and outside of the vagina. It can take weeks, months or even years before the warts appear after having sex or any genital-to-genital contact with an infected partner. Cervical cancer caused by HPV typically does not manifest any symptoms until it is fairly advanced. A yearly PAP (Papanicolaou) smear test is often the only way cervical cancer is detected.

Histology

• The histology of HPV-related benign (not dangerous or progressive) abnormalities includes the formation of genital warts and other types of minor abnormal cell growth, both inside and outside of the vagina or anus. Abnormal cell growth due to certain types of HPV can be described as cells with an enlarged, irregular nucleus surrounded by a clear “halo.” All of these types of abnormal cellular changes are considered low-risk. In contrast, the histology of HPV-related pre-cancerous or cancerous (malignant) cellular changes includes moderate to severe abnormal cell growth. These high-risk growths can include carcinoma-in-situ, or a cluster of cancerous cells that has not yet invaded other parts of the body. The risk of developing invasive-type cancers increases as the severity of abnormal cellular changes increases.

Prevention/Solution

• Sexual abstinence is by far the best prevention against contracting the human papilloma virus, but it is not a very realistic course of action. Condoms provide limited protection since they still allow some genital-to-genital contact between partners. Remember, an individual may be infected with HPV without any visible signs. A vaccine against HPV 16 and HPV 18 called Gardasil is available to girls as young as 9 years old. Ideally the vaccine should be given to girls 11 to 12 years of age, but it can be administered to women up to 26 years of age. As of 2010, the vaccine is expected to be approved for boys also.

Warning

• There is currently no cure for HPV. Symptoms such as genital warts can be treated effectively but may still recur. Although men can contract the virus as well, and HPV has been known to cause anal and penile cancer, there is currently no test to check for the high-risk types of HPV in men. Sexually active teens are usually unaware that any type of genital contact can transmit the disease, even when actual intercourse is not involved.