Inverted Papilloma of the Nose and Sinuses

About inverted papilloma

Last reviewed: November 3, 2026

In brief

An inverted papilloma (often shortened to "IP") is a growth that starts in the lining of the nose or the paranasal sinuses, the air-filled spaces in the bones of the face; doctors call this the "sinonasal" region. "Inverted" describes the way the tumor grows inward, into the tissue and sometimes the bone beneath it, rather than only outward like most nasal polyps [1]. It is the most common member of the "Schneiderian papilloma" family, the papillomas that arise from the lining of the nose [1]. It is different from the HPV-related papillomas of the mouth and throat and from laryngeal papillomas of the voice box.

Although it is not cancer, inverted papilloma is taken seriously for three reasons [2, 3]:

• It can keep growing and press on or erode nearby bone.

• It can come back after it is removed (recurrence).

• A small number of inverted papillomas contain, or later develop, a cancer called squamous cell carcinoma.

An overview of all tumors in this area is on the nose and sinus tumors Learning Center page. A numbered reference list is at the end of this page.

How common is it

Inverted papilloma is uncommon, affecting roughly 0.2 to 1.5 people per 100,000 each year and making up about 0.5% to 4% of tumors that start in the nose [1].

• It is 2 to 5 times more common in men than in women.

• Most people are diagnosed between their 40s and 70s, with an average age in the mid-50s to 60 [1, 3].

• About 95% of the time it involves only one side of the nose.

• It usually starts on the side wall of the nasal cavity and can extend into the maxillary sinus (behind the cheek) or the ethmoid sinuses (between the eyes); less often it reaches the frontal sinus (forehead) or the sphenoid sinus (deep behind the nose) [1].

Causes

The cause is not fully understood. Research points to several factors:

• Gene changes in the tumor cells. Most inverted papillomas carry a change (mutation) in a gene called EGFR. A smaller group instead contain human papillomavirus (HPV). These appear to be two separate pathways to the same tumor [4].

• HPV. When present, HPV may slightly raise the chance of recurrence or of cancer developing [5]. Inverted papilloma is not considered contagious.

• Smoking. Studies disagree about whether smoking causes inverted papilloma, but some link smoking to a higher chance of cancerous change [5]. Information on quitting is on the tobacco page.

• Workplace exposures. Long-term exposure to wood dust, leather dust, nickel, formaldehyde, welding fumes and organic solvents has been linked to sinonasal cancers and possibly to cancer developing within inverted papilloma [6].

No specific personal behavior is known to directly cause an inverted papilloma.

Symptoms and evaluation

Symptoms

Symptoms are often mild and resemble ordinary sinus problems, so many people have them for months or years before the diagnosis is made [3]. Common symptoms include [1, 3]:

• Blocked or stuffy nose on one side, the most common symptom

• Nosebleeds

• Runny nose or drainage, sometimes from one side only

• Decreased sense of smell

• Headache or facial pressure

• Less often, with a large tumor: a watery eye, double vision or a bulging eye

Sinus symptoms that stay on one side, especially with nosebleeds, are a recognized reason for an examination of the inside of the nose by an ear, nose and throat (ENT) specialist.

Evaluation

Nasal endoscopy. A thin camera (endoscope) is passed into the numbed nose, usually in the office. An inverted papilloma often looks like a bumpy, fleshy growth; it can resemble a polyp but is usually redder or pinker and less translucent [1].

CT scan. A CT shows the bones of the sinuses and is used to plan surgery. A small area of thickened bone often marks the spot where the tumor is attached. This attachment site matters because it must be fully treated to lower the chance of recurrence [1, 7].

MRI scan. An MRI shows soft tissue better than CT and helps separate tumor from trapped mucus or swelling. Inverted papilloma often shows a wavy, brain-like pattern on MRI, called a "convoluted cerebriform pattern," which strongly suggests the diagnosis [8, 9]. Areas where this pattern is missing can be a warning sign of cancer and may prompt a closer look.

Biopsy. A small tissue sample is examined under the microscope by a pathologist, often in the office (biopsy). A small sample can sometimes miss the papilloma, or miss a small area of cancer deeper in the tumor [10], so the final diagnosis is made after the whole tumor is removed and examined. For this reason the diagnosis or treatment plan can change after surgery.

Staging

The extent of the tumor is described by a stage. The most widely used system, the Krouse system, runs from T1 (limited to the nasal cavity) to T4 (spread beyond the nose and sinuses, or cancer present) [11]. Higher stages are linked to a higher chance of recurrence [12]. Other systems, such as one developed for endoscopic surgery, group tumors by the sinuses involved and the recurrence rates seen in each group [13].

Treatment

Surgery

Surgery to remove the entire tumor is the standard treatment. No medicine, nasal spray or pill is known to shrink or cure an inverted papilloma [2].

Endoscopic surgery. Most inverted papillomas are now removed with endoscopic sinus surgery through the nostrils, using a camera and small instruments, usually with no cuts on the face. Large studies show this approach works at least as well as older "open" operations, with a lower chance of recurrence: in one large review the tumor came back in about 14% of people after endoscopic surgery and about 19% after open surgery [14], and some expert centers using newer techniques report about 5% [15, 16].

During surgery:

• The bulk of the tumor is removed and the exact attachment site is identified.

• The lining at the attachment site is removed, and the bone underneath is usually drilled to remove tumor cells that grew into it. In one study the tumor came back in about half of patients when only the lining was removed, compared with about 5% when the bone was drilled [7].

• A tumor in the maxillary sinus may require a wider opening of that sinus (endoscopic medial maxillectomy or a related approach) [16], and a tumor in the frontal sinus may require a wider opening called a Draf III procedure.

• All removed tissue is sent to a pathologist to confirm the diagnosis and check for cancer.

Open or combined surgery. A small incision, for example under the upper lip or near the eyebrow, is sometimes needed to reach a tumor that cannot be reached safely with the endoscope.

Radiation therapy

Radiation is not a routine treatment for benign inverted papilloma. It may be used in special situations, such as a tumor that cannot be fully removed, keeps returning, or contains cancer [2, 17].

When cancer is found

If squamous cell carcinoma is found in or with the papilloma, treatment is more intensive, usually surgery and often radiation afterward, sometimes with chemotherapy, planned by a head and neck cancer team [2]. Outcomes are less favorable than for benign inverted papilloma, although some studies suggest cancers arising from an inverted papilloma may do somewhat better than sinus cancers that start on their own [18]. More on treatment options is on the sinus tumor treatments page.

How often cancer is involved

Across many studies, about 7% of people have cancer already present when the inverted papilloma is first found, and about 3% to 4% develop cancer later, roughly 1 in 10 or fewer overall [19]. Cancer can appear many years later, in some reports more than a decade after surgery [20]. Most people with inverted papilloma never develop cancer, and when the tumor is benign and fully removed the long-term outlook is excellent [3].

Recovery and follow-up

Recovery after surgery

Recovery varies, and the surgeon's own instructions take priority. In general [21, 22]:

• Pain is usually mild to moderate and worst in the first 3 days; many people do well with acetaminophen (Tylenol), and few need opioid pain medicine.

• Stuffiness, mucus and crusting are normal for several weeks while the nose heals.

• Saline rinses are a key part of healing, using only distilled, sterile or previously boiled and cooled water, never plain tap water, with regular cleaning of the rinse device.

• In-office cleanings of the nose are common in the first weeks.

• Hard nose blowing, heavy lifting, strenuous exercise and flying are usually avoided for a short time, and sneezing with the mouth open reduces pressure in the nose.

More detail is on the recovery after sinus surgery for a mass page.

Possible side effects of surgery

Endoscopic surgery is generally safe, and serious problems are uncommon [15, 23]. Possible side effects include:

• Bleeding after surgery, rarely needing a return to the operating room

• Numbness of the cheek, upper lip or front teeth, more common after wider maxillary sinus surgery and often improving over time

• A watery eye if the tear drainage duct is affected, usually correctable if it persists

• Scar tissue or a mucus-filled cyst (mucocele) that may need treatment later

• Rarely, a leak of the fluid around the brain (CSF leak) or injury to the eye area, more likely when the tumor is near the skull base or the eye (see intracranial injury and eye-area injury from sinus surgery)

Recurrence

Even after excellent surgery, inverted papilloma can return, often at the same spot because a few cells were left behind or grew back. Early detection of a recurrence makes it easier to treat.

• Modern endoscopic series report recurrence rates of about 5% to 15%, depending on technique, tumor location and size, and length of follow-up [14, 15].

• Most recurrences appear in the first 2 to 3 years, but late recurrences happen: in one study about 1 in 5 appeared after 5 years [24], and in another about 1 in 4 appeared after 10 years [20].

• Factors that raise the chance of recurrence include tumor that could not be fully removed, involvement of the frontal sinus or other hard-to-reach areas, a more advanced stage, previous surgery for the same tumor, and dysplasia (abnormal-looking cells under the microscope) [7, 25, 26].

• In one study almost half of patients stopped attending follow-up visits too early [20].

Follow-up (surveillance)

There is no single official schedule; follow-up is tailored to the tumor and the surgery. A typical plan based on published expert experience [3, 15, 24, 27]:

Endoscopy is the main follow-up tool, with a biopsy if anything looks unusual. MRI is used when scar tissue blocks the view or the tumor was in a deep or hard-to-see place [15, 26]. Many experts favor lifelong yearly checks because the tumor can return, or cancer can appear, many years later [20, 24].

Warning signs after treatment

Symptoms that commonly prompt contact with the ENT team include new or returning blockage on one side of the nose, nosebleeds (especially repeated ones), bloody or foul-smelling drainage, new facial pain, swelling or numbness, and loosening teeth or a sore on the roof of the mouth.

Symptoms generally treated as emergencies include heavy bleeding that does not stop after 15 to 20 minutes of firm pressure; clear, watery fluid dripping from the nose after surgery, especially when leaning forward; sudden vision changes, double vision, eye swelling or eye pain; and severe headache, stiff neck, high fever or confusion.

Questions often asked of the care team

• Where exactly did the tumor start, and what stage is it?

• Was any dysplasia or cancer found in the tissue?

• Was all of the tumor removed?

• Is imaging needed, and how often?

• What follow-up schedule is planned, and for how long?

• What side effects should be watched for after surgery?

Suggestions for preparing for a visit are on the Make the Most of Your Sinus Appointment page.

Additional links

Related pages on this site: sinus tumors, sinus tumor treatments, nose and sinus tumors (Learning Center), nose and sinus anatomy, nasal endoscopy, sinus surgery, recovery after sinus surgery for a mass.

Summary

• Inverted papilloma is a benign tumor of the nose and sinuses that grows inward and can wear away bone [1].

• The most common symptom is a blocked nose on one side [3].

• Diagnosis uses nasal endoscopy, CT, MRI and biopsy; the final diagnosis comes after the whole tumor is removed [8, 10].

• Surgery, usually endoscopic through the nose, is the main treatment; no medicine is known to cure it [2, 14].

• A small number of cases involve cancer, at diagnosis or later [19].

• The tumor can come back, sometimes many years later, so long-term, often lifelong, follow-up is common [20, 24].

References

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