Changes in Smell and Brain Tumors: What Patients Should Know
Can a Brain Tumor Affect Your Sense of Smell?
Yes. Changes in smell can be an early or associated symptom of certain brain tumors, particularly those involving the skull base, pituitary gland, frontal lobes, or olfactory pathways.
Patients may experience:
- loss of smell (anosmia)
- reduced smell (hyposmia)
- distorted smells (parosmia)
- phantom smells, such as smelling smoke or chemicals when none are present (phantosmia)
While smell changes are common in sinus disease and viral infections, persistent or unexplained smell disturbances—especially when paired with headaches, vision changes, or hormonal symptoms—should be medically evaluated.
Is Smelling Smoke a Sign of a Brain Tumor?
Smelling smoke when no source is present is known as phantosmia, a type of olfactory hallucination.
Possible causes include:
- irritation or compression of the olfactory nerve
- tumors near the frontal lobe or skull base
- pituitary or parasellar tumors
- prior brain or sinus surgery
- seizures or neurologic conditions
Phantosmia does not automatically mean a brain tumor, but when it is:
- recurrent
- worsening
- associated with neurologic symptoms
It warrants evaluation by a specialist experienced in brain and skull base disorders.
Why Smell Is Neurologically Important
Smell is one of the most powerful and least appreciated senses. The olfactory system:
- is located at the roof of the nasal cavity
- connects directly to brain regions involved in memory and emotion
- plays a critical role in safety, alerting us to smoke, gas, spoiled food, and environmental danger
Loss of smell has been associated with:
- depression
- anxiety
- reduced appetite
- diminished quality of life
Smell Changes After Pituitary or Skull Base Surgery
Patients frequently ask:
“Is it normal to have a bad or reduced sense of smell after pituitary surgery?”
Historically, smell loss after endoscopic skull base or pituitary surgery was reported in up to 40% of cases, largely due to disruption of the nasal septum and olfactory epithelium.
At Pacific Neuroscience Institute, preserving smell is a major surgical priority.
Smell Preservation in Endoscopic Endonasal Surgery
In 2009, surgeons at PNI developed a novel olfactory-preserving surgical approach designed to protect the septal olfactory epithelium, the tissue responsible for smell.
Clinical Outcomes
In a prospective study of over 140 patients:
- 0% experienced complete loss of smell
- only 4% had a mild decrease
- over 20% experienced improved smell after surgery
Smell improvement occurred because nasal and sinus conditions were treated at the same time as the tumor, including:
- deviated septum correction
- sinus infection drainage
- removal of nasal polyps or cysts
- reduction of swollen turbinates
Dual Benefits of Endoscopic Skull Base Surgery
Modern endoscopic skull base and pituitary surgery allows surgeons to:
- treat brain or pituitary tumors
- correct nasal and sinus disease simultaneously
- preserve or improve smell
- minimize trauma to healthy tissue
This dual-focus approach improves both neurologic outcomes and quality of life.
When to See a Specialist
You should consider evaluation by a brain tumor or skull base specialist if you experience:
- persistent smell loss
- phantom smells (burning, smoke, chemicals)
- smell changes with vision loss or headaches
- smell disturbances after pituitary surgery that do not improve
Expert Skull Base and Pituitary Care at PNI
At Pacific Neuroscience Institute, our skull base and pituitary surgery teams prioritize:
- tumor removal with maximal safety
- preservation of neurologic function
- protection of smell whenever possible
- multidisciplinary care tailored to each patient
Smell matters—not just for safety, but for memory, emotion, and everyday enjoyment of life. Our goal is to treat the disease without taking away the senses that make life meaningful.
“What’s in a name? That which we call a rose by any other name would smell as sweet.”
— William Shakespeare
Frequently Asked Questions About Smell Changes and Brain Tumors
Can a brain tumor cause changes in smell?
Yes. Certain brain tumors—especially those involving the skull base, pituitary gland, frontal lobes, or olfactory pathways—can affect the sense of smell. Patients may experience reduced smell, distorted smells, or phantom smells even before a tumor is diagnosed.
Is smelling smoke or burning a sign of a brain tumor?
Smelling smoke or burning when no source is present is called phantosmia. While phantosmia can have many causes (such as sinus disease or neurologic conditions), it can also be associated with brain or skull base tumors that affect the olfactory nerve. Persistent or worsening phantom smells should be evaluated by a specialist.
Can pituitary tumors affect your sense of smell?
Yes. Pituitary tumors themselves—or their proximity to the olfactory structures and nasal cavity—can contribute to smell changes. Additionally, nasal or sinus obstruction related to pituitary tumors may also impact smell.
Is it normal to have a bad smell in the nose after pituitary surgery
Temporary smell disturbances can occur after pituitary or skull base surgery, especially in the early healing phase. However, persistent foul or unusual smells should be discussed with your surgeon, as they may indicate nasal healing issues, infection, or sinus inflammation.
Will I lose my sense of smell after endoscopic pituitary or skull base surgery?
With modern endoscopic endonasal techniques, permanent smell loss is uncommon. At specialized centers like Pacific Neuroscience Institute, surgical approaches are designed to preserve the olfactory epithelium, and studies show very low rates of long-term smell impairment.
Can smell improve after brain or pituitary tumor surgery?
Yes. In some cases, smell actually improves after surgery—particularly when nasal or sinus conditions (such as deviated septum, sinus infections, or nasal polyps) are corrected during the same procedure.
When should smell changes be evaluated by a specialist?
You should seek evaluation if smell changes are:
- persistent or unexplained
- worsening over time
- associated with headaches, vision changes, or hormonal symptoms
- occurring after pituitary or skull base surgery without improvement
A specialist experienced in brain tumors and skull base disorders can help determine the cause.
Who should I see for smell changes related to brain tumors or surgery?
Patients should be evaluated by a multidisciplinary team that includes neurosurgeons and skull base specialists experienced in endoscopic endonasal surgery, particularly when smell changes may be related to pituitary tumors, skull base tumors, or prior surgery.
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