Chronic Rhinosinusitis: Understanding Your Pathology Report

Section Editor: Jason Wasserman MD PhD FRCPC
July 15, 2026

Chronic rhinosinusitis is a common medical condition caused by long-lasting inflammation of the nasal cavity and the paranasal sinuses, the air-filled spaces in the bones around the nose. It is defined by symptoms that last at least 12 weeks, and it typically affects adults. The term “rhinosinusitis” describes inflammation involving both the nasal cavity and the sinuses, while “sinusitis” describes inflammation of the sinuses alone. Because inflammation rarely affects the sinuses without also involving the nasal cavity, doctors prefer the term rhinosinusitis. Chronic rhinosinusitis is not cancer and is not a precancerous condition. This article will help you understand the findings in your pathology report, what each term means, and why it matters for your care.

What causes chronic rhinosinusitis?

Chronic rhinosinusitis can be caused by anything that leads to chronic inflammation of the nasal cavity and paranasal sinuses. Common contributing factors include allergies, repeated upper respiratory tract infections, smoking, and exposure to airborne irritants. It is also associated with cystic fibrosis, aspirin intolerance (a condition sometimes called aspirin-exacerbated respiratory disease), and certain autoimmune diseases. In many people, more than one factor is involved, and the inflammation continues even after the original trigger has resolved. People with chronic rhinosinusitis are more likely to develop a noncancerous growth in the nasal cavity, or sinuses, called a sinonasal inflammatory polyp.

What are the symptoms?

The symptoms of chronic rhinosinusitis last at least 12 weeks and often fluctuate in severity. The most common symptoms are nasal congestion or blockage, nasal discharge (which may run from the front of the nose or drip down the back of the throat), facial pressure or pain, and a reduced or absent sense of smell. Many people also describe fatigue, headache, or a persistent cough. Because these symptoms overlap with those of allergies and common colds, chronic rhinosinusitis is often left undiagnosed for a long time.

How is the diagnosis made?

Chronic rhinosinusitis is primarily a clinical diagnosis, meaning it is based on symptoms lasting at least 12 weeks, combined with evidence of inflammation seen either during a nasal endoscopy (an examination using a thin scope passed through the nose) or on a CT scan. The pathology report supports this diagnosis rather than making it on its own.

Tissue is usually examined by a pathologist after a small sample is removed in a procedure called a biopsy, or after tissue is removed during endoscopic sinus surgery performed to relieve symptoms. Under the microscope, chronic rhinosinusitis shows large numbers of inflammatory cells, including neutrophils, eosinophils, plasma cells, and lymphocytes. These cells are typically found both in the epithelium (the thin layer of tissue covering the inside of the nasal cavity and sinuses) and in the stroma (the supporting layer of tissue beneath it). The stroma often appears pale under the microscope because it is filled with fluid, a condition called edema. When these same features are seen in a growth projecting from the surface of the tissue, it is called a sinonasal inflammatory polyp.

Your report may also describe which type of inflammatory cell predominates, because this distinction has become clinically important. When most of the inflammatory cells in the stroma are eosinophils, the condition may be described as eosinophilic or allergic chronic rhinosinusitis. This pattern is part of what doctors call type 2 inflammation, and it is associated with nasal polyps, asthma, and a higher chance that symptoms will return after surgery. When neutrophils predominate instead, the pattern is described as non-eosinophilic, or non-type 2. Identifying which pattern is present helps guide treatment decisions, as described below.

What other findings may be reported?

Because the tissue removed from the nasal cavity and sinuses can contain more than just inflammation, the pathologist examines it for several other findings that may appear in your report.

Nasal polyps — Noncancerous swellings of the lining that project into the nasal cavity. Their presence divides chronic rhinosinusitis into two forms: with nasal polyps and without nasal polyps. This distinction affects treatment planning.
Fungal elements — The pathologist looks for fungus within the mucus or tissue. Fungus trapped in thick mucus alongside eosinophils suggests a specific form called allergic fungal rhinosinusitis, while fungus invading the tissue itself is a much more serious finding that requires urgent treatment. Special stains or fungal testing may be performed.
Bacteria — Some reports mention bacteria or features suggesting infection, which may prompt a culture to identify the organism.
Granulomas or vasculitis — Granulomas (organized clusters of immune cells) or vasculitis (inflammation of blood vessels) are uncommon findings that can point to an underlying autoimmune condition, such as granulomatosis with polyangiitis, rather than ordinary chronic rhinosinusitis. These findings usually lead to blood tests and referral to a specialist.
Changes in the surface lining — Long-standing inflammation can cause the lining to thicken or change, and the pathologist confirms that no precancerous or cancerous change is present.

What happens after the diagnosis?

Chronic rhinosinusitis is a long-term condition that is managed rather than cured, and the goal of treatment is to control inflammation, relieve symptoms, and improve quality of life. Care is usually provided by a family doctor, an ear, nose, and throat (ENT) specialist, and sometimes an allergist or immunologist.

Initial management typically involves rinsing the nose with saline and using intranasal corticosteroid sprays to reduce inflammation, as well as addressing contributing factors such as allergies or smoking. Antibiotics may be considered when there are signs of bacterial infection. When symptoms persist despite these measures, endoscopic sinus surgery may be considered to open blocked sinuses and remove polyps; this is often when the tissue described in your pathology report was obtained.

The findings in your pathology report help guide what comes next. If the report describes eosinophil-rich (type 2) inflammation, particularly alongside nasal polyps, this identifies a group of patients who may benefit from targeted drugs called biologics. These medications block specific parts of the type 2 inflammatory pathway, and several are approved for chronic rhinosinusitis with nasal polyps that remains uncontrolled despite standard treatment, including dupilumab, omalizumab, mepolizumab, and tezepelumab. Eligibility depends on factors your care team will assess, including the severity of your symptoms, whether you have had surgery, and whether you have related conditions such as asthma. If the report instead identifies fungal elements, granulomas, or vasculitis, the next steps are directed at that specific finding.

Questions to ask your doctor

Did my report describe mostly eosinophils, and does that mean I have type 2 inflammation?
Do I have chronic rhinosinusitis with or without nasal polyps?
Were any fungal elements seen in my tissue or mucus?
Were any granulomas or vasculitis seen, and do I need testing for an autoimmune condition?
Should I be tested for allergies, aspirin intolerance, or asthma?
What treatment options are appropriate for my type of chronic rhinosinusitis?
Given my pathology findings, might I be a candidate for a biologic medication?
What is the chance that my symptoms or polyps will come back after surgery?
What can I do at home to reduce inflammation and prevent flare-ups?
Was there anything unexpected in my pathology report?