Penile cancer is a disease in which malignant (cancer) cells form in the tissues of the penis. The penis is a rod-shaped male reproductive organ that passes sperm and urine from the body.
The main part of the penis is known as the shaft, and the head of the penis is called the glans. At birth, the glans is covered by a piece of skin called the foreskin, or prepuce. The foreskin is often removed in infant boys in an operation called a circumcision.
The penis contains two types of erectile tissue (spongy tissue with blood vessels that fill with blood to make an erection):
- The two columns of erectile tissue that form most of the penis. They lie on either side of the upper part of the organ.
- The single column of erectile tissue that forms a small portion of the penis. This chamber widens at its end to form the glans and surrounds the urethra (the thin tube that starts at the bladder and runs through the penis. Urine and semen travel through the urethra to pass from the body).
Sometimes, growths can develop on the penis that are abnormal but are not cancers (they are benign). These lesions can look like warts or irritated patches of skin. Like penile cancer, they are most often found on the glans or on the foreskin, but they can also occur along the shaft of the penis.
- These are wart-like growths that look like tiny cauliflowers. Some are so small that they can only be seen when the skin is looked at under a magnifying lens. Others may be as large as an inch or more across. Condylomas are caused by infection with human papilloma virus (HPV).
- In this condition, abnormal cells are seen only in the surface layer of the penile skin. This condition tends to occur in younger men and is seen as small, reddish, pimple-like patches on the shaft of the penis. Bowenoid papulosis can be mistaken for early-stage cancer called carcinoma in situ
(CIS), but most doctors agree it is not cancer or a pre-cancerous condition.
Each of the tissues in the penis contains several types of cells. Different types of penile cancer can develop in each kind of cell. The differences are important because they determine the seriousness of the cancer and the type of treatment needed.
Almost all penile cancers start in skin cells of the penis.
Squamous Cell Carcinoma
About 95% of penile cancers develop from flat skin cells called squamous cells
. Squamous cell cancers can develop anywhere on the penis. Most of these cancers are found on the foreskin (in men who have not been circumcised) or on the glans. These tumors tend to grow slowly. If they are found at an early stage, these tumors can usually be cured.
- This is an uncommon form of squamous cell cancer that can occur in the skin in many areas. A verrucous carcinoma growing on the penis is also known as Buschke-Lowenstein tumor. This cancer looks like a large benign genital wart. These cancers tend to grow slowly but can sometimes grow very large. They can invade deeply into surrounding tissue, but they rarely spread to other parts of the body.
Carcinoma in situ (CIS)
- This is the earliest stage of squamous cell cancer of the penis. In this stage the cancer cells are only found in the top layers of skin. They have not yet grown into the deeper tissues of the penis. Of the glans, it is sometimes called erythroplasia of Queyrat and on the shaft of the penis (or other parts of the genitals), it is called Bowen’s disease.
Melanoma is a type of skin cancer that starts in melanocytes, the cells that make the brownish color to the skin that helps protect it from the sun. These cancers tend to grow and spread quickly and are more dangerous than other types of skin cancer.
Basal cell cancer is another type of skin cancer that can develop on the penis. It makes up less than 2% of penile cancers. This type of cancer is slow-growing and rarely spreads to other parts of the body.
Adenocarcinoma (Paget Disease of the Penis)
This very rare type of penile cancer can develop from sweat glands in the skin of the penis. It can be very hard to tell apart from carcinoma in situ of the penis. At first, the cancer cells spread within the skin. Later, cells can invade, growing into the tissues underneath the skin and spreading to lymph nodes.