A papilloma is a benign (noncancerous) growth that forms on the surface of skin or the lining of internal organs. These growths develop from epithelial cells, the type of cells that cover your body’s outer surfaces and line hollow organs like the bladder, airways, and breast ducts. Papillomas typically grow outward, forming small finger-like projections, and they can appear nearly anywhere on the body.
What Makes a Papilloma Different From Cancer
Under a microscope, papillomas have a distinctive structure: small branching projections, each with a core of connective tissue and blood vessels that feeds the growing tissue above it. The cells covering these projections match whatever tissue they grew from, whether that’s skin, bladder lining, or breast duct tissue.
The key feature that separates a papilloma from a cancer is the basement membrane, a thin boundary layer beneath the surface cells. In a benign papilloma, this membrane stays intact. The growing cells remain on their side of the line and don’t push into deeper tissue. When cells break through that boundary and invade surrounding tissue, the growth is no longer a papilloma. It’s a carcinoma.
Where Papillomas Develop
Papillomas can form on any surface lined by epithelial cells. The most common locations include the skin (where they often appear as warts), the oral cavity, tongue, lips, eyelids, throat, larynx (voice box), esophagus, cervix, genital tract, and breast ducts. The name used for each one often reflects its location: a growth in a breast duct is called an intraductal papilloma, one on the vocal cords is a laryngeal papilloma, and one inside the nasal sinuses is a sinonasal papilloma.
Despite sharing the same basic structure, papillomas at different sites can behave very differently. Skin warts are common and usually harmless. Papillomas in the airway can obstruct breathing. And certain nasal papillomas are locally aggressive, meaning they tend to come back after removal and carry a meaningful risk of turning cancerous.
Causes: HPV and Beyond
Most papillomas are caused by human papillomavirus (HPV). There are over 200 strains of HPV, and different strains tend to target different parts of the body. Some cause common skin warts, others cause genital warts, and still others affect the throat or airways. HPV spreads through direct contact, including skin-to-skin contact and sexual contact.
Not all papillomas are linked to HPV, though. Intraductal papillomas in the breast, for example, develop without any known viral cause. The triggers for these non-viral papillomas are less well understood.
Breast Papillomas
Intraductal papillomas form inside the milk ducts of the breast. A solitary papilloma typically grows in one of the large ducts near the nipple, while multiple papillomas (called papillomatosis) develop in smaller ducts farther from the nipple.
About half of people with intraductal papillomas have no symptoms at all. When symptoms do appear, the most common is nipple discharge, which may be bloody, occurring in roughly 35% of cases. Less often, people notice a palpable lump (about 9%) or breast pain (about 3%). Because many papillomas are asymptomatic, they’re frequently discovered during routine imaging rather than from symptoms alone.
On ultrasound, benign papillomas tend to have a regular, round or oval shape. Irregular shapes and the presence of calcifications are more common in papillomas that turn out to be malignant, which is one reason imaging and biopsy are important for distinguishing harmless growths from concerning ones.
Respiratory Papillomatosis
Recurrent respiratory papillomatosis (RRP) is a rare condition in which papillomas grow on the vocal cords and upper airways. Symptoms range from mild hoarseness to serious airway obstruction, depending on the size and location of the growths. The condition can occur in both children and adults.
The primary treatment is endoscopic surgery to remove the growths. Roughly one in ten patients is cured after a single procedure, but the majority experience regrowth. That’s what makes RRP so challenging: it tends to come back, sometimes requiring repeated surgeries over years. Antiviral medications and immune-boosting therapies have been tried as add-on treatments, but their effectiveness remains uncertain.
Nasal and Sinus Papillomas
Sinonasal inverted papillomas deserve special attention because they behave more aggressively than papillomas elsewhere. “Inverted” refers to the way these growths push inward into underlying tissue rather than projecting outward like a typical papilloma.
Surgical removal is the standard treatment, but recurrence rates are high. In one study of 44 patients followed for over a decade, 34% experienced a recurrence, with regrowth happening an average of about two years after surgery but sometimes appearing as late as ten years out. The potential for malignant transformation in sinonasal inverted papillomas ranges from 5% to 15%, which is substantially higher than papillomas at most other sites. This is why long-term follow-up after surgery is essential.
Can a Papilloma Become Cancer?
Most papillomas stay benign and never become cancerous. But the risk isn’t zero, and it varies significantly by location and type.
For laryngeal papillomatosis, malignant transformation into squamous cell carcinoma occurs in about 1% to 4% of cases. Factors that increase this risk include infection with high-risk HPV strains, tobacco use, prior radiation exposure, a high number of recurrences, and disease that has persisted for more than ten years. Immune suppression and gastroesophageal reflux may also play a role.
Sinonasal inverted papillomas carry a higher conversion risk of 5% to 15%. Breast papillomas, particularly multiple papillomas (papillomatosis), are also associated with a modestly increased risk of breast cancer, which is why they’re often removed and followed closely.
How Papillomas Are Removed
Treatment depends on the type, location, and symptoms. Many papillomas, especially small skin growths, don’t need treatment at all. When removal is needed, several options exist.
- Surgical excision: Cutting the growth out with a scalpel. This is the standard approach for breast papillomas and nasal inverted papillomas, where getting clear margins matters.
- Cryotherapy: Freezing the growth with liquid nitrogen. Commonly used for skin warts and genital warts, cryotherapy clears about 79% to 88% of genital warts but sometimes requires two or three sessions.
- Laser therapy: CO2 laser vaporization is highly effective, clearing about 95% of genital warts in a single treatment in one clinical trial, compared to 46% for cryotherapy. Laser treatment also had a lower recurrence rate.
- Endoscopic surgery: Used for papillomas inside the airways, sinuses, or other internal structures where traditional surgery would be too invasive.
For oral papillomas, recurrence after removal is relatively low regardless of the method used. In one study, recurrences appeared in about 10% to 18% of cases and always showed up within 15 months. Nasal and airway papillomas, by contrast, have much higher recurrence rates and often require ongoing monitoring for years after the initial procedure.