Esthesioneuroblastoma is a very rare type of cancer that involves the nasal cavity. This condition is marked by the development of malignant tumors that are believed to originate from the olfactory epithelium an individual. The condition is also known as olfactory neuroblastoma, and can cause difficulty in smelling, breathing, vision and taste loss.
The condition was first characterized in the year 1924.
Although around 1200 cases of Esthesioneuroblastoma have been reported since 1924, 80% of them have been identified only in the last 25 years. The disease can develop in patients of all age groups. It most frequently affects people within the 40-70 years age group as well as teenagers in some cases. It accounts for 3% to 5% of all types of nasal neoplasms. Although the condition is mostly seen in Caucasians, other races have also been found to be affected by it. ENB is more frequently seen in women than in men.
The factors responsible for Esthesioneuroblastoma are not known. The exact cell where this condition develops is also a subject of debate. Medical experts suspect a number of areas from where this condition might originate. These include:
Picture 1 – Esthesioneuroblastoma
- Autonomic ganglia of the nasal mucosa
- Ectodermal olfactory placode
- Sphenopalatine ganglion
- Olfactory epithelium
The most conjectured site of origin is the olfactory epithelium. There is a strong possibility that various factors combine to give rise to this blastoma, including genetics, environmental pollution and cigarette smoking.
Esthesioneuroblastoma is a tumor that generally grows slowly, although some of them behave rather aggressively. The initial signs and symptoms are commonly subtle in nature. The average time gap between the onset of the initial symptoms and the medical diagnosis is nearly 6 months. The symptoms that are most frequently seen in Esthesioneuroblastoma patients are unilateral nasal obstructions which are followed by epistaxis.
The symptoms that are generally caused by Esthesioneuroblastoma are non-specific, which means that they can be presented by many other common nasal disorders, including the long-term rhinosinusitis or the allergic polypoid sinus disorder as well as several other paranasal and nasal neoplasms. However, the unilateral manner of the symptoms generally suggests the presence of a neoplasm. The various signs and symptoms of the disorder are generally classified in the following manner:
- Obstructions in development
- Unilateral polyp
- Changes in the sense of smell
- Oral ulcers
- Loose teeth
- Difficulties in healing after a tooth extraction
These include development of mass due to metastasis in the neck area.
- Changes in vision
- Excessive tearing from eyes (Lacrimation)
These involve painful sensations in the ear.
Additional growth of tumor can be laterally directed within orbit, thereby giving rise to symptoms like:
- Extraocular movement paralysis
- Intracranial symptoms and other complications
Neurological and nasal symptoms are most commonly seen whereas oral and facial symptoms are very rare initial presentations.
A doctor would first conduct a thorough physical examination of a patient’s eyes, throat and nose and check for signs that might aid in diagnosis. Follow-up tests include:
Physical tests can be followed by an endoscopic examination wherein an endoscope (a thin and flexible tube) is inserted into the mouth or nose of the patient. The tube is fitted with a small camera that allows a doctor check for signs of tumor.
An intranasal biopsy can help to diagnose the disease at an early stage. A complete nasal evaluation is recommended for patients who are having unilateral nasal obstruction along with a recurrent epistaxis that lasts longer than 1 or 2 months.
Standard X-ray films do not have much role to play in the diagnosis of Esthesioneuroblastoma. A coronal thin-cut CT (computed tomography) scan is generally the radiological examination that is chosen initially. Although ENB does not have any specific radiological characteristic and appears generally as a mass of homogeneous soft-tissue, obtaining CT images help in accurate staging of the condition. They also assist in precise evaluation of erosion of cribriform plate as well as the bone of skull base.
MRI (magnetic resonance imaging) scans are necessary to study the intraorbital, sinonasal or intracranial extensions of ENB. Since the details of the bony erosions are demonstrated better by the CT images and the MRI scans reveal more precise images of the soft tissue structures, both scans are generally required in majority of the patients.
The optic nerves might get affected by the tumor due to their closeness to olfactory nerves. They may also be injured by radiation or during a radical surgery. Hence, a pre-operative ophthalmological evaluation is necessary to obtain a vision baseline and evaluate any possibilities for existing visual deficits.
Staging for the disorder is based on the Kadish System, which focuses on its extent of metastasizing:
- Kadish A: This stage is confined only to the nasal cavity (18%).
- Kadish B: This stage extends to the paranasal sinuses (32%).
- Kadish C: The stage C extends beyond the nasal cavity and the paranasal sinuses (49%).
- Kadish D: The fourth stage extends beyond the lymph nodes or the distant metastases.
Esthesioneuroblastoma Differential Diagnosis
Diagnosis for Esthesioneuroblastoma can be difficult as it is a very rare form of cancer and its symptoms are similar to many other common varieties of cancer occurring around the neck and head region. Due to this reason, while trying to establish a diagnosis which is reliable and conclusive, a doctor should try to differentiate ENB from these other similar-appearing conditions. The differential diagnoses for Esthesioneuroblastoma includes making sure that the difficulties experienced by sufferers are not the result of conditions such as:
- Metastatic Cancer
- Malignant Melanoma
- Non-Hodgkin Lymphoma
- Extramedullary Plasmacytoma
The classic treatment methods that are used to manage Esthesioneuroblastoma are mainly based on surgery as well as radiotherapy as the unique modalities. A combination of these two types of therapeutic measures can also be used. Most medical institutions opt for surgery as the primary choice of treatment, which is then followed by post-operative irradiation.
During a palate resection, an upper dental prosthesis is going to be constructed prior to surgery and then put in place when the procedure ends. This is done to achieve a separation between the oral cavity and the nasal cavity, thereby allowing adequate oral nutrition. This prosthesis needs to be adjusted after ablation of nasal packing and then following the tissue scarring and/or the retraction that takes place within 6 months from the completion of treatment.
Picture 2 – Esthesioneuroblastoma Image
Surgery for ENB is managed by a group of craniofacial experts who also have a number of neurosurgeons as an essential part of the team. The usual surgical procedure involves a combined craniofacial resection. The surgeon creates an incision into a skull in a process known as craniotomy, and a head-and-neck surgeon creates an incision along the sides of the nose through a process referred to as lateral rhinotomy. Small tumors can be removed by the trans-nasal endoscopic approach, wherein an endoscope is used to get rid of the cancer. Metastatic tumors that have spread to the neck and the parotid gland are removed by parotidectomy, which involves removal of the affected tissue.
Patients are generally released on the first post-operative day. If a lumbar drain is used, the sufferer needs to remain in strict bed rest for as long as recommended by the doctor.
Esthesioneuroblastoma can be treated by using radiation therapy. It may include IMRT (intensity modulated radiation therapy) and/or Gamma Knife radiosurgery. These procedures allow effective management of the cancer along with limiting the use of radiation essentially to the important normal tissues of regions like: the brain, brain stem, optic nerves, eyes and the spinal cord.
Radiation therapy can be used in isolation or it can be combined with chemotherapy if the Esthesioneuroblastoma is very large or in a stage where removal through surgery is difficult.
Chemotherapy is often used to reduce the size of a giant tumor so that it can be effectively removed by surgical procedures. In some cases, chemotherapeutic chemicals are used alongside radiation therapy to get rid of any additional cancer cells that might remain after surgery.
The outcome for the disease depends on the stage of the tumor. Management of tumor is more effective during the earlier stages. Sometimes, the condition can recur after treatment if the cancer cells have not been completely removed. Once the tumor is removed, patients can continue living a normal life. However, the tumor can metastasize rapidly if not treated in time and might become fatal.
Esthesioneuroblastoma is a rare type of cancer that can cause difficulties in the senses of vision, nasal functions, hearing and taste. If ignored, the condition can grow out of proportions and have life-threatening consequences for its sufferers. Hence, immediate treatment is essential for the disorder.