Olfactory neuroblastoma is a rare cancer of nose which develops in the olfactory epithelium on upper part of nose and paranasal sinuses. In 1924, Berger described this malignant tumor. Olfactory neuroblastoma, originates from the nerves in the nose that are meant to detect smell. It is a slow growing tumor, but sometimes the growth can be rapid spreading to paranasal sinuses and adjacent structures.
Symptoms may present as nasal stuffiness, post nasal drip, nosebleed etc. The non specific symptoms make early diagnosis difficult. The exact reason for olfactory neuroblastoma is obscure, but research has found exposure to chemical fumes, wood dust etc can increase the risk of its development.Treatment consists of surgical removal and radiation. Early diagnosis and treatment is of key importance for good prognosis for this tumor.
Causes Of Olfactory Neuroblastoma
Olfactory neuroblastoma is an uncommon malignant tumor of nose. Its incidence is about 0.4 in million population. About 2 % of sinonasal tumor can be olfactory neuroblastoma. The tumor arises from special nerve cells that are found in the upper part of nasal cavity. These cells are sensory neuroepithelial cells that are involved in sensing smell.
The exact cause of olfactory neuroblastoma is not clearly understood. But it is believed to occur due to exposure to environmental toxins.Exposure to harmful chemical fumes and dust can increase the risk for its occurrence. Wood dust, exposure to fumes emitted while dealing with production of nickel, cadmium, glues and formaldyhyde increase the risk for development of such nasal malignancy.
Sometimes tobacco smoke is also suspected to trigger development of this cancer. There is equal predilection for males and females. It usually develops in sixth and seventh decade of life or in middle age.
Signs And Symptoms Of Olfactory Neuroblastoma
Olfactory neuroblastoma arises from the nerves that are involved in sense of smell in the upper part of nose.This malignant tumor grows slowly. One of the most characteristic symptoms is congestion and blockage in one nostril. The blockage may be present since long term, may be since months and years.
At least 50 percent of people suffering from olfactory neuroblastoma complain of nose bleeding (epistaxis). Even though the tumor arises from olfactory neuroepithelium, anosmia (loss of sense of smell) is not commonly seen in these patients. Other prominent symptoms include:
- Pain around the orbits of eyes.
- Stuffy nose on one side.
- Post nasal drip since long time.
- Discharge of pus from nose.
- Numbness in face and mouth.
- Loose teeth
- The sense of smell may be decreased but it is not completely absent.
- Neck lymph nodes are enlarged in size.
- Recurrent infection in sinuses.
- In case if the tumor has become large and has infiltrated nearby structures patient may suffer from certain other symptoms such as swelling of face, vision problems, and certain neurological symptoms on face such as numbness on face and tooth etc.
- In some cases patient may get ear ache and facial paralysis.
Diagnosis And Treatment Of Olfactory Neuroblastoma
The nasal cavity can be examined with several techniques. Most of the olfactory neuroblastoma is detected with the help of MRI, CT scan and X-rays. In certain cases biopsy may be necessary.
Since olfactory neuroblastoma is rare malignant tumor, there is no consensus for its treatment strategy. However, most surgeons opine surgical removal of the tumor is best mode of treatment. Nowadays the resection of tumor is done using endoscopic endonasal approach (EEA). It is minimal invasive surgery which can be done through the natural nasal pathway. Patient does not require incision on the nose from outside.
The surgeon removes the tumor and recovery is faster of the dissected area. There are fewer complications with endoscopic surgery. After the surgery, patient may undergo radiotherapy to kill the remaining left over malignant cells. Despite aggressive therapy recurrence of the tumor and distant metastasis can occur even after regular follow ups