A penis cyst is a closed, fluid-filled sac that can form on or under the skin of the penis. These bumps are common, benign (non-cancerous), and not related to sexually transmitted infections (STIs). While the appearance of a new lump can be concerning, most are harmless.
Types and Potential Causes of Penis Cysts
Penis cysts can develop for several reasons, often related to blocked glands. One common type is the epidermoid cyst, which forms when surface skin cells, composed of keratin, move deeper into the skin and multiply. This can happen when a hair follicle becomes blocked. Sebaceous cysts occur when oil-producing sebaceous glands are damaged or blocked.
Another type is the median raphe cyst, which is congenital, meaning it is present from birth. These cysts form along the midline of the penis when tissue becomes trapped during fetal development. They often go unnoticed until adolescence or adulthood when they may increase in size.
Identifying a Cyst Versus Other Bumps
A typical cyst feels like a small, movable lump just beneath the skin. It is usually round, smooth, and painless unless it becomes inflamed or infected. The skin over the cyst generally appears normal in color and texture. Cysts tend to appear as single, larger bumps.
In contrast, other common penile bumps have different characteristics. Genital warts, caused by the human papillomavirus (HPV), often appear in clusters and can have a rough, cauliflower-like texture. Pimples, or folliculitis, are smaller, may have a white or black head, and are associated with an inflamed hair follicle at the base of the penis. Pearly penile papules are harmless, small, dome-shaped bumps that typically form in neat rows around the head of the penis.
It’s also important to be aware of the signs of more serious conditions, although they are much rarer. A cancerous lesion might appear as a sore that doesn’t heal, a flat growth, or a lump that is firm and fixed in place. Changes in the color or shape of a bump are also noteworthy.
When to Seek Medical Attention and Treatment
While most penis cysts are harmless, there are specific situations where medical advice is recommended. You should see a doctor if a cyst becomes painful, shows signs of infection such as redness or swelling, or drains pus. Rapid growth, bleeding, or interference with urination or sexual function also warrants a medical evaluation. Significant cosmetic concern or emotional distress are also valid reasons to seek care.
The diagnostic process typically involves a physical examination by a healthcare provider. In most cases, a visual and tactile assessment is sufficient to identify the type of cyst. Based on the diagnosis, a doctor might recommend one of several management approaches. For asymptomatic and harmless cysts, simple observation is often the chosen course.
If a cyst is infected or causing discomfort, a doctor might perform an incision and drainage to relieve symptoms, although this may not prevent recurrence. For cysts that are persistently bothersome or for cosmetic reasons, surgical excision is an option. This procedure involves the complete removal of the cyst and its containing sac, which helps prevent it from returning. In cases of infection, a course of antibiotics may also be prescribed.