Introduction:
Olfactory neuroblastoma is a very rare tumor that involves the nasal tissues, olfactory nerves (nerve supplying to nose), and cribriform plate and can also spread to other body parts like lungs, skull bones, brain, and neck. It is also called “olfactory carcinoma” as the cancer is derived from neuroectodermal olfactory cells that are present in the upper part of the nasal cavity, cribriform plate of the ethmoid, nasal septum, and roof of the nose. Olfactory nerves damaged by the tumor cause loss of smell sensation in people. Olfactory carcinoma can occur at any age but are more common in adults.
What Is the Prevalence of Olfactory Neuroblastoma?
It is a rare type of cancer that accounts for three to four percent of total nasal tumors.
What Is the Incidence of Olfactory Neuroblastoma?
It affects one in 2.5 million people every year and is more common in people in the age group of 50 to 70 years old.
What Are the Causes of Olfactory Neuroblastoma?
The exact cause of olfactory neuroblastoma is still unknown. But it is found by research that it is caused by abnormal alteration of parts of DNA (deoxyribonucleic acid), mostly involving chromosome 2, chromosome 5, chromosome 6, chromosome 7, and chromosome 20.
What Are the Signs and Symptoms of Olfactory Neuroblastoma?
Various signs and symptoms related to olfactory carcinoma are:
-
Loss of smell sensation.
-
Pain around the eyes.
-
Epistaxis (bleeding from the nose).
-
Pus drainage from the nose.
-
Blurred vision.
-
Nose blockade.
-
Postnasal drip (nasal drainage in the throat)
-
Swelling near eyes, nose, and face.
What Are the Different Grades of Olfactory Neuroblastoma?
Olfactory neuroblastoma is classified into four grades:
-
Grade A: When the tumor involves only the nasal cavity.
-
Grade B: When the tumor involves the nasal cavity, along with all the paranasal sinuses (Sinus or hollow cavity present lateral to the nose).
-
Grade C: When the tumor involves the nasal cavity and paranasal sinus and also spreads to the cribriform plate, intracranial spaces, and skull base.
-
Grade D: Along with areas of Grade C, it also involves lymph nodes of the neck and spreads to other parts of the body like the lungs, liver, and brain.
How Can We Diagnose Olfactory Neuroblastoma?
Diagnostic aids for olfactory neuroblastoma are:
-
Clinical Examination and History: Complete clinical examination of the nasal cavity is done to check for swelling, draining pus from the nose that is collected and sent to the lab for investigations. History of symptoms like loss of smell, watery eyes, and pain/tenderness near the eyes should be noted.
-
Computed Tomography (CT) Scans: These scans are done to check the size, location, and extent of the tumor spread. The presence of a dumbbell shaped tumor across the cribriform plate (part of ethmoid bone that forms the roof of the nasal cavity) is one of the characteristic findings observed in the scan.
The unique dumb-bell shape of the tumor mass is formed due to the presence of the upper mass of the tumor in the intracranial fossa (skull bone cavity) and the lower mass of the tumor in the nasal cavity, and the middle point is formed by the cribriform plate.
-
Magnetic Resonance Imaging (MRI): These scans help to check the spread of cancer in various areas of the skull, eyes, sinus cavities, and brain. A contrast media like gadolinium is used before doing the scan to enhance the visibility of the areas of spread.
-
Biopsy: A sample of small tissue is taken from the tumor and sent to the lab to confirm the presence of olfactory carcinoma.
-
Positron Emission Tomography (PET) Scan: A radioactive material is injected through the vein, and three-dimensional scans are taken. It is used to assess the involvement of the lymph nodes of the neck and the spread of cancer to various areas of the body. It also helps to grade cancer based on the diagnosis.
What Is the Treatment Plan For Olfactory Neuroblastoma?
Various treatment modalities for olfactory carcinoma are:
-
Radiotherapy: Radiation therapy is given to the patient to kill the cancer cells and prevent their recurrence.
-
Surgical Removal of the Tumor: The tumor mass is removed surgically with some amount of healthy tissue margins so that all tumor cells are removed for safety to prevent the recurrence of the tumor. It is done by either nasal endoscopic surgery or open craniotomy resection, depending on the extent of the tumor.
-
Chemotherapy: Chemotherapeutic agents such as Cisplatin and Carboplatin are prescribed to the patient along with radiation therapy, and after the surgery is done in advance if the cancer is spread to other parts of the body.
Can Olfactory Neuroblastoma Recur After Surgery?
Yes, although the surgery completely removes the tumor mass, any cancer cell behind can lead to the recurrence of the tumor. Post-surgical radiotherapy and chemotherapy play a tremendous role in the prevention of the recurrence of the tumor, especially in grade C tumor cases where cancer has involved lymph nodes of the neck and other body parts like skull bones, lungs, and brain.
What Are the Complications After Surgery for Olfactory Neuroblastoma?
Complications that can occur after surgery are:
-
CSF rhinorrhea (cerebrospinal fluid leak from the nasal cavity).
-
Hematoma (collection of blood between the tissue spaces).
-
Loss of smell.
-
Recurrence of the tumor.
-
Change in the facial aesthetics (look of the face changes after removal of the damaged bone).
Conclusion:
Olfactory neuroblastoma is a very rare tumor and can affect anyone during adulthood. Symptoms related to olfactory carcinomas like loss of smell, watery eyes, difficulty in breathing through the nose, and nasal discharge should be noticed and reported to the doctor immediately for diagnosis and management of the tumor in the early stage for a satisfactory outcome of the treatment. The tumor that is not diagnosed early and advances to grade C makes the treatment very complex for both the patients and the doctor, as the outcome of the treatment is not good because of the spread of cancer to different areas of the body.
However, there are various treatment modalities available for an advanced grade of olfactory neuroblastoma, but the risk of recurrence is more in such cases, so post-surgical follow-up with the doctor for radiation therapy and chemotherapy is crucial to prevent the recurrence of the tumor in advanced cases.