What Could a Lump on My Perineum Be?

A lump on the perineum, the area between the genitals and the anus, can be caused by dozens of different conditions, and the vast majority are benign. Epidermoid cysts, abscesses, blocked glands, and warts account for most cases. That said, a few rare but serious possibilities exist, and the location makes self-diagnosis unreliable. What matters most is the lump’s texture, how quickly it appeared, whether it hurts, and whether it changes with your menstrual cycle or activities.

Epidermoid Cysts

One of the most common lumps you can get almost anywhere on your body is an epidermoid cyst, a slow-growing, firm, usually painless bump just under the skin. These form when surface skin cells get trapped beneath the surface and continue producing keratin, creating a smooth, round mass. While epidermoid cysts most often show up on the face, neck, and trunk, they do occasionally appear in the perineal region. When they occur there, repeated friction, minor injuries, and past surgical procedures like episiotomy may be contributing factors.¹

These cysts are more common in men than women (roughly twice as often) and tend to appear in people in their twenties through forties. The good news is that the outlook is excellent. Even after surgical removal, the recurrence rate is only about 3%.¹ An epidermoid cyst typically feels like a smooth, round marble under the skin. It moves slightly when you press on it, and it is usually not painful unless it becomes infected, at which point it may turn red, swell, and become tender.

Bartholin Gland Cysts and Abscesses

For women, one of the most frequent causes of a lump near the perineum is a Bartholin gland cyst. The Bartholin glands sit on either side of the vaginal opening and produce a small amount of lubricating fluid. When the duct of one of these glands gets blocked, fluid backs up and forms a cyst. These are among the most common fluid-filled masses in the vulvar area, occurring at a rate of about 0.5 per 1,000 people per year.²

A small Bartholin cyst may cause no symptoms at all, and many women only discover one during a routine exam. Larger cysts and abscesses, however, tend to present with noticeable redness, swelling, and sometimes significant pain, especially when sitting or walking.³ An abscess forms when a cyst becomes infected, and these can grow quickly over a day or two, becoming very painful and warm to the touch. Small cysts sometimes resolve on their own or with warm soaks, but abscesses typically require drainage by a healthcare provider.

Perianal Abscesses

A perianal abscess is an infected, pus-filled pocket near the anus that can easily feel like a perineal lump, especially if it forms toward the front. These abscesses typically develop when a small gland inside the anal canal becomes blocked and bacteria multiply. The hallmark symptoms are pain and swelling: in one study of patients who had perianal abscesses drained, anal pain and perianal swelling were present in 95% of cases.⁴

Unlike a cyst, a perianal abscess usually comes on fast. You might go from feeling fine to having a throbbing, hot, tender lump within a couple of days. Sitting may become unbearable. These abscesses almost always need medical drainage because antibiotics alone rarely clear a walled-off pocket of pus. One thing worth knowing: even after successful drainage, about one in five patients in the same study went on to develop a fistula (an abnormal tunnel between the anal canal and the skin) within two months.⁴ So follow-up care after an abscess is drained matters a lot.

Hidradenitis Suppurativa

If your perineal lumps keep coming back, or if you have recurring painful nodules in other skin-fold areas like the armpits or groin, you may be dealing with hidradenitis suppurativa (HS). This is a chronic inflammatory skin disorder that causes painful nodules, abscesses, and over time, scarring and sinus tracts, which are tunnels under the skin that connect lesions to each other.⁵

HS is frequently misdiagnosed early on as simple boils or ingrown hairs. The anogenital region is one of the more challenging locations for it, both because of the functional demands on the area and because of the difficulty of reconstruction when surgical treatment is needed. Severe HS in the perineal area can cause a significant reduction in both physical and psychological quality of life.⁶ If you notice a pattern of lumps that flare, drain, heal with scarring, and then return in the same general area, bring this up with a dermatologist specifically. Early recognition can open up treatment options, including biologic medications, that may slow progression.

Genital Warts

Genital warts caused by human papillomavirus (HPV) can appear anywhere in the anogenital region, including the perineum. They are caused by the virus triggering an overgrowth of squamous skin cells.⁷ Small warts may look and feel like tiny, rough, flesh-colored bumps. They can be flat or slightly raised, and they sometimes cluster together in a pattern often described as cauliflower-like.⁸

Most genital warts are painless, which is one way they differ from abscesses and inflamed cysts. They are also usually softer and more superficial, sitting on the skin’s surface rather than deep under it. A single small wart is easy to miss, but once you notice one and look carefully, there are often several. Left untreated, they can grow or spread. Certain HPV strains responsible for anogenital warts have also been associated with an elevated risk of squamous cell carcinoma.⁹ This is another reason to get any unexplained perineal bumps evaluated rather than assume they are harmless.

Lumps Linked to Childbirth and Surgery

If you have had a vaginal delivery, particularly one involving an episiotomy or forceps, your perineal lump may be related to scar tissue from that procedure. Episiotomy scars can occasionally develop unusual complications. In rare cases, endometrial tissue (the tissue that normally lines the uterus) can implant in an episiotomy scar, creating a firm, painful nodule that typically worsens with menstrual periods.¹⁰ This cyclical pain pattern is a key distinguishing feature: if a perineal lump swells and hurts in sync with your cycle, scar endometriosis should be considered.

Another post-surgical possibility is a traumatic neuroma, which is a tangle of nerve tissue that forms when a nerve is cut or damaged during surgery. One case report documented a painful neuroma developing in an episiotomy scar, where the tissue had grown around old surgical thread.¹¹ Neuromas tend to be extremely tender, often producing sharp, shooting pain rather than the dull ache of a cyst.

Urethral Diverticula and Periurethral Cysts

Women who feel a lump toward the front of the perineum, particularly one that seems to sit just under the urethra, may have a urethral diverticulum or a periurethral cyst. A urethral diverticulum is an outpouching of the urethral wall that fills with fluid and can present as a tender, hard mass along the front vaginal wall.¹² These can mimic vaginal wall cysts on physical exam, so imaging is often needed to tell them apart.

The symptoms can help distinguish the two. Women with urethral diverticula tend to experience more urinary symptoms compared to those with simpler periurethral cysts, including pain during urination, dribbling after urination, recurrent urinary tract infections, and urethral discharge.¹³ If a perineal or vaginal lump comes with urinary complaints, that pattern is worth mentioning to your provider because it changes how the lump should be evaluated.

Cyclist’s Nodule and Other Activity-Related Lumps

If you spend a lot of time on a bicycle seat, a firm perineal lump might be a cyclist’s nodule (technically called perineal nodular induration). This is a benign pseudotumor of the perineal soft tissues that develops almost exclusively in people who engage in prolonged saddle-based sports, particularly road cycling.¹⁴ The nodule forms from chronic repetitive trauma: pressure, vibration, and shearing forces between the sit bones and a hard saddle compress the tissue over and over.¹⁵

These nodules are firm, usually located between the sit bones, and can be tender. They tend to appear after months or years of high-mileage cycling. The condition is uncommon, so many doctors and even dermatologists may not immediately recognize it. If you are an avid cyclist with a perineal lump, mention your riding habits during the exam. Treatment often involves saddle modifications and sometimes surgical excision for persistent cases.

Male-Specific Causes

Men have a pair of small glands called Cowper’s glands (bulbourethral glands) located deep in the perineum, just below the prostate. These glands can occasionally develop cystic dilations called syringoceles, which are rare but can present as a swelling or mass in the perineal area. They are more commonly seen in children but do occur in adults.¹⁶ When a Cowper’s gland cyst becomes infected, it can cause significant perineal swelling and pain, sometimes mimicking a perianal abscess. MRI is typically needed to confirm the diagnosis because these lie deeper than most superficial cysts.¹⁷

Vulvar Varicosities

Sometimes what feels like a lump near the perineum is not a solid mass at all, but a cluster of swollen veins. Vulvar varicosities look like bluish-purple, soft, compressible bulges, often described as having a “cluster of grapes” appearance. They are typically painless unless a clot forms inside one.¹⁸ These are most commonly seen during pregnancy, when increased blood volume and pressure from the growing uterus on pelvic veins can cause dilation. They often improve significantly after delivery.

The distinguishing feature of a varicosity is its softness and compressibility. If you press on it and it flattens, then refills when you let go, it is likely vascular rather than a solid cyst or tumor. They also tend to worsen with prolonged standing and improve when you lie down.

Rare Tumors Worth Knowing About

The overwhelming majority of perineal lumps are benign, but a few uncommon tumors can occur in this region. A lipoma, a painless, slow-growing mass of fatty tissue, can appear in the perianal and perineal area.¹⁹ These feel soft and rubbery, are easy to move under the skin, and are entirely benign. They can grow quite large if left alone for years.

A more unusual possibility is aggressive angiomyxoma, a rare tumor of the connective tissue that tends to occur in the pelvic and perineal regions of young adult women. Despite its alarming name, this tumor is benign and slow-growing.²⁰ It does not spread to other parts of the body. The “aggressive” label refers to its tendency to infiltrate surrounding tissue locally and to recur after removal.²¹ Aggressive angiomyxomas are sometimes initially mistaken for Bartholin cysts or other common vulvar masses because they present in a similar location. The distinction usually becomes clear on MRI or after biopsy.

How Perineal Lumps Are Diagnosed

For many perineal lumps, a physical exam is the starting point. Your provider can often distinguish between common causes based on the lump’s location, texture, and your symptoms. Ultrasound is useful for evaluating superficial, palpable abnormalities and is particularly helpful for genital injuries. When more detail is needed, MRI provides much better tissue contrast and can characterize conditions that ultrasound cannot fully sort out.²² MRI is not always the first-line test because it is less readily available and more expensive, but it is the go-to tool for deeper, more complex, or diagnostically uncertain masses.

Some features that help guide the workup include:

• Speed of onset: A lump that appeared within days and is hot and painful suggests an abscess or infection. A lump that has been slowly growing for months is more likely a cyst or benign tumor.
• Pain pattern: Cyclical pain tied to menstrual periods points toward scar endometriosis. Constant throbbing pain with fever suggests an abscess.
• Texture: Soft and compressible suggests a varicosity or lipoma. Firm and round suggests a cyst. Hard and fixed may warrant imaging to rule out something more unusual.
• Urinary symptoms: Dribbling, painful urination, or recurrent infections alongside a lump near the urethra suggest a urethral diverticulum.
• Activity link: A firm lump between the sit bones in a regular cyclist points toward cyclist’s nodule.

Why People Delay Getting Help

The perineum is one of the most common areas where people put off seeking medical attention, and embarrassment is a major reason. Research on delays in care for pelvic floor problems found that among women who waited at least a year before seeing a doctor, roughly 18% cited shame or embarrassment about revealing the problem.²³ Other common reasons included not believing the problem could be solved, not having time, and assuming the symptoms were normal for their age.

Embarrassment can also lead to a process of normalizing symptoms. Women may convince themselves that a perineal lump is just part of aging or something to be endured rather than treated.²⁴ The real cost of delay is that conditions like hidradenitis suppurativa, which respond better to early treatment, may progress unnecessarily. And while the vast majority of perineal lumps are benign, the small number that are not benefit from early detection. If you have noticed a new or changing lump, the exam itself is usually brief and straightforward, and the provider has seen it many times before.