An inverted papilloma is a benign tumor that develops in the nasal cavity and adjacent paranasal sinuses. These growths are uncommon, accounting for a small fraction of all tumors originating in the nose. Their name comes from a distinctive growth pattern where the tumor extends inward into the underlying tissue, rather than outward. While not cancerous, they are known to be locally aggressive, meaning they can impact nearby structures.
Causes and Associated Symptoms
The precise cause of inverted papillomas is not fully understood, but research points to several contributing factors. A strong association has been identified with certain strains of the Human Papillomavirus (HPV), specifically subtypes 6, 11, 16, and 18. Chronic inflammation, such as that seen in long-term sinusitis, is also considered a possible cause. Environmental factors, including smoking, are also thought to be potential risk factors.
Symptoms of an inverted papilloma can mimic more common nasal problems, which may delay detection. The most frequent sign is unilateral nasal obstruction, where blockage affects only one side of the nose. Other common signs include:
- A persistent runny nose (rhinorrhea) on the affected side
- Recurrent nosebleeds (epistaxis)
- Facial pain or pressure in the sinus areas
- A diminished sense of smell (anosmia)
In some cases, especially when the growth is small, individuals may not notice any symptoms at all.
Diagnosis and Medical Evaluation
The diagnostic process is a multi-step evaluation managed by an Ear, Nose, and Throat (ENT) specialist. The initial step involves a physical examination and a discussion of symptoms. Following this, the physician will likely perform a nasal endoscopy. This procedure uses a thin, flexible tube with a camera on the end to visually inspect the nasal passages and the sinus openings for any abnormal growths.
To understand the full size and location of the tumor, imaging studies are ordered. A Computed Tomography (CT) scan is the primary imaging tool used, as it provides detailed cross-sectional images of the nasal cavity and sinuses. These scans help the surgeon see the extent of the growth and its relationship to surrounding structures, such as the eye socket or the base of the skull. In some situations, a Magnetic Resonance Imaging (MRI) scan may also be used to get a better view of soft tissues.
While endoscopy and imaging can strongly suggest the presence of an inverted papilloma, a definitive diagnosis requires a biopsy. During this procedure, a small sample of the tumor tissue is removed and sent to a laboratory for analysis by a pathologist. Microscopic examination of the tissue confirms the diagnosis and allows for the detection of any cancerous cells within the benign growth.
Malignant Potential
An inverted papilloma is a benign growth, but it possesses a known potential for malignant transformation. This means that while the tumor itself is not cancerous, it can harbor or develop into a form of cancer over time. The type of cancer most frequently associated with these growths is squamous cell carcinoma.
The reported rate of cancerous changes occurring within an inverted papilloma falls between 5% and 15% of cases. This risk underscores the necessity for a thorough initial diagnosis, including a biopsy to check for any existing malignancy from the outset.
The possibility of malignant transformation is a primary reason why complete removal of the tumor is recommended. If left untreated, the risk of a benign papilloma becoming cancerous can increase over several years.
Treatment and Recurrence
The standard treatment for an inverted papilloma is complete surgical removal of the tumor. Modern surgical techniques have advanced significantly, with the most common approach being endoscopic surgery performed through the nostrils. This minimally invasive method avoids external incisions and allows for a quicker recovery compared to older, open surgical procedures.
A key aspect of the surgery is not just removing the soft tissue of the papilloma but also addressing the underlying bone to which it is attached. Surgeons will often drill down or remove a small portion of this bone to reduce the likelihood of the tumor growing back.
Inverted papillomas have a notable tendency to recur, even after what appears to be a successful surgery. Recurrence rates can be as high as 34.1% in some reported studies. This high rate of return makes long-term monitoring a part of patient care.
Following surgery, patients will have regular follow-up appointments with their ENT specialist. These check-ups typically involve periodic nasal endoscopy to visually inspect the surgical site for any signs of new growth. This surveillance is often more frequent in the first couple of years after surgery and may continue for many years.