Olfactory Neuroblastoma Diagnosis: Tests You Should Know

Unusual issues with the nose don’t often cause instant worry, however, ongoing problems should certainly be investigated properly. Olfactory neuroblastoma is a rare form of cancer which develops from the specialised nerve tissue found in the upper part of the nose. Getting to the right diagnosis, quickly, is extremely important for the success of treatment and the patient’s long-term health. 

This unusual tumour is quite different from the neuroblastoma which children get; it mainly affects adults in their fifties and sixties. Getting a diagnosis involves a number of doctors and advanced tests to work out how far the disease has spread. Knowing what each test shows assists patients in being actively involved in planning their treatment. 

First Clinical Checks 

Symptoms generally start with a blockage in one nostril which gets steadily worse over several months. Patients frequently think this is due to hay fever or a long-term sinus infection, and so put off going to the doctor. Nosebleeds happen as the tumour destroys the blood vessels in the lining of the nose. These bleeds can be slight, or very heavy and need immediate treatment. 

A loss of smell happens when the tumour damages the smell nerve endings directly. A lot of patients notice this gradually, and sometimes think it’s due to getting older, or a cold or flu. Headaches mean the tumour has grown into the structures around it, and is putting pressure on them. A detailed medical history helps to tell olfactory neuroblastoma apart from more common problems in the nose. 

What a Physical Examination Finds 

Ear, nose and throat doctors do an anterior rhinoscopy - using special lights to look inside the nose. This often shows a reddish or greyish growth in the upper part of the nasal passage. The surface of the tumour can be smooth or rough, depending on how it’s growing. Feeling the neck checks for swollen glands which may mean the disease has spread to that area. 

Checking the cranial nerves sees whether the tumour has grown into nearby structures. Changes in vision or how the eyes move show the eye sockets are affected. Testing facial feeling finds any pressure on the trigeminal nerve from growth to the side. A full neurological examination creates a base level of function before treatment starts. 

Nasal Endoscopy 

Flexible fibreoptic endoscopy gives a detailed view of the whole of the nasal cavity and the nasopharynx. A spray of local anaesthetic makes the nose numb, so the procedure is bearable without any sedation. The endoscope sends high-definition pictures to screens, which allows doctors to map the tumour exactly. Surgeons can work out where the tumour is attached, and its relationship to important structures. 

This check is usually done in a clinic, not in a theatre, giving an immediate diagnosis. The endoscopist notes the size, appearance and precise location of the tumour. Photos or video recordings are kept as a permanent record for treatment planning. Most patients feel only a little discomfort during this short procedure. 

Taking Tissue Biopsies 

A definite diagnosis needs a microscopic examination of tumour tissue taken in a biopsy. An endoscopic-guided biopsy lets doctors take a sample accurately, while they can see the tumour directly. Enough tissue needs to be taken to allow pathologists to do all the necessary studies. The biopsy site usually bleeds very little and heals without any help. 

Pathologists look at the structure of the tissue and the characteristics of the individual cells under a microscope. Olfactory neuroblastoma shows specific patterns, including rosette formations and nerve cell development. Immunohistochemistry staining finds specific proteins which confirm the diagnosis. Electron microscopy may give more detail in cases which are not clear. 

CT Scanning 

Computed tomography makes detailed cross-section pictures showing bone and soft tissue anatomy. High-resolution CT scans show how bone is being destroyed, which shows how invasive the tumour is. The base of the skull gets special attention, as tumours often erode this area. Coronal, sagittal and axial views give a complete three-dimensional understanding. 

Intravenous contrast enhancement helps to tell the tumour apart from inflammation and healthy tissue around it. Neuroblastoma cancer usually shows moderate enhancement on contrast scans. CT is best at showing calcifications and bone involvement, better than other imaging methods. These scans help with surgical planning and the design of radiation fields. 

MRI Scans 

Magnetic resonance imaging gives better soft tissue detail than CT scanning. T1-weighted images show anatomy, while T2-weighted images highlight swelling and how far the tumour has spread. Giving gadolinium contrast improves the tumour tissue, showing the edges more clearly. MRI shows growth into the brain and the dura mater very clearly. 

Diffusion-weighted imaging helps to tell the tumour apart from changes after treatment during follow-up. Advanced sequences like perfusion MRI assess the tumour’s blood flow. These functional studies give information beyond simple anatomy. Most patients put up with the 45 to 60 minute scan well, despite being in a confined space. 

PET Scanning 

Positron emission tomography finds metabolically active tissue using radioactive glucose tracers. Olfactory neuroblastoma usually shows increased glucose uptake, which shows high cellular activity. PET scans can show unexpected distant spread of cancer – distant metastases – that usual scans may not find, and this full-body check is especially useful for staging the disease. 

PET-CT combinations put metabolic and anatomical details together in one image. Joining this information improves how well the disease is diagnosed when compared to using one of the scans on its own; however, insurance approval sometimes restricts when PET scans can be done, although places like Fortis Healthcare, Gurgaon, have really good imaging services. The test needs a period of fasting before it, and will take about two hours including the wait.  

Blood Tests in the Laboratory 

Full blood counts give a starting point for blood-related health before treatment starts. Anaemia can happen because of long-term sickness or repeated bleeding. White blood cell counts measure how well the immune system is working. Platelet counts show how well blood clots – which is important when planning operations. 

Full metabolic panels check kidney and liver function. As these organs process chemotherapy drugs, how well they are working to start with affects what treatment is chosen. Measuring electrolytes makes sure the body’s chemical balance is correct. Thyroid function tests look for hormone problems that surgery or radiotherapy might make worse. 

Tumour Marker Tests 

Certain substances in the blood help to follow how active the disease is, and how well treatment is working. Levels of neuron-specific enolase are linked to the amount of tumour in some patients. Taking measurements regularly shows if levels fall as treatment goes on. If markers go up during follow-up, this may mean the disease is back before scans can show a visible tumour. 

Chromogranin A is another marker which is sometimes high in neuroendocrine tumours. Not all olfactory neuroblastomas make measurable markers, so they cannot always be used. When they are high, markers give a useful way of checking things without needing frequent scans. Normal marker levels do not mean the disease isn’t there, or isn’t getting worse. 

Smell Tests 

Proper smell tests measure the loss of smell, and track how it changes with time. Patients name different smells at different strengths. Standard tests give objective results, unlike what patients themselves say. Complete anosmia means a lot of damage to the smell nerves. 

These assessments give a baseline before treatment which will further damage smell. Knowing what the smell was like before treatment helps to set sensible expectations for recovery. Most patients do not get their normal smell back after the tumour is removed. Other ways of dealing with things help to keep quality of life good, despite the lasting loss of smell. 

Eye Examinations 

Eye doctors check vision when tumours are near the eye sockets. Tests of visual acuity find small changes from pressure on the optic nerve. Mapping visual fields finds problems with side vision. Looking into the eye with a fundoscope shows the optic disc for signs of pressure inside the skull. 

Tests of eye movements show if cranial nerves are not working properly because of tumour growth. Measurements of proptosis – bulging of the eyeball – show how much orbital masses are pushing the eye forward. These tests help to plan treatment to protect vision. Regular checks go on throughout treatment to find any worsening that needs dealing with. 

Hearing Tests 

Hearing assessments give a baseline before chemotherapy which might damage hearing. Pure tone audiometry measures hearing at different frequencies. Speech discrimination testing checks how well people can hear speech. These baselines let treatment-related hearing loss be found. 

Neuroblastoma chemotherapy often includes platinum drugs which damage the inner ear. Regular hearing tests during treatment allow doses to be changed if hearing gets worse. Some hearing loss cannot be put right, so stopping it through checking is important. Hearing aids help when loss of hearing is serious enough to cause problems. 

Nutritional Assessment 

Dieticians check how well people are nourished, as not being nourished makes treatment less well tolerated, and gives worse results. History of weight and what people currently eat shows what is not enough. Analysis of body composition separates loss of muscle from loss of fat. Not having enough micronutrients needs to be put right before treatment starts. 

Nutritional support plans deal with problems expected from treatment. Difficulty swallowing often happens from surgery or radiotherapy to the head and neck. A feeding tube may be needed to give enough calories. Keeping people nourished supports healing and the immune system during treatment. 

Genetic Advice 

About 1 to 2 per cent of neuroblastoma is caused by genetic mutations which are passed down in families. Checking family history finds patterns which suggest an inherited tendency. Genetic tests check for particular mutations when the family history causes worry. Results affect what is recommended for family members in terms of checks. 

Most olfactory neuroblastoma cases happen by chance, and do not have a hereditary cause. Genetic counselors explain how things are passed on in families, and what testing means. Positive results mean cascade testing in the family, and better screening. This helps families make sensible reproductive choices. 

Multidisciplinary Tumour Board 

Complex cases are looked at by teams including surgeons, oncologists, radiologists and pathologists. Each expert gives their knowledge to plan the best treatment. Discussion considers all the findings from diagnosis fully. Agreed recommendations include what guidelines are based on evidence, and what the hospital has found. 

Patients benefit from the knowledge of the group, rather than just one person. How treatment is given and what sort of treatment is considered carefully. Other approaches for difficult anatomy are looked at thoroughly. This working together improves results, and respects what patients want, and their circumstances.