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Esthesioneuroblastoma (ENB)

Esthesioneuroblastoma is a very rare tumor, which occurs in the nasal cavity. Between 1978 and 1990 only 84 esthesioneuroblastomas were reported in the United States. They are believed to arise in the olfactory (smelling) nerves that originate in the nose and travel into the brain. The tumors have a bimodal age distribution occurring most commonly in teenagers and the sixth decade of life. It was first described in 1924 by Berger and Luc in the French medical literature.

Symptoms of Esthesioneuroblastoma

Most patients with esthesioneuroblastoma present with symptoms of nasal obstruction (inability to breath through the involved nostril), nosebleed or both. These tumors can spread to the lymph nodes and to other areas of the body. The incidence of metastasis (spread to other body areas) is ~50%.

The most frequent symptoms are a unilateral nasal obstruction (70%), followed by epistaxis (46%). These are common in many nasal diseases, including long-term rhinosinusitis or allergic polypoid sinus disease. Many patients undergo sinus surgery, only to have the diagnosis established as an unexpected pathological finding.

Further growth of the tumor can be directed laterally within the orbit and results in proptosis, extraocular movement paralysis, and blindness, or, it superiorly produces intracranial complications. Facial and oral symptoms are rare.

Diagnosis of Esthesioneuroblastoma

Early referral for an intranasal biopsy is key to early diagnosis. A patient with a unilateral nasal obstruction and/or a recurrent epistaxis lasting longer than 1-2 months should undergo a thorough nasal evaluation by an otolaryngologist, although the cost-effectiveness of this approach has not been evaluated.

Radiologic studies: Both CT and MRI studies usually are required in the majority of patients. Biopsy: Once the radiologic studies are completed, a biopsy will be taken after administering a topical anesthesia, under direct vision through a rigid endoscope. The role of an accurate histopathological diagnosis before initiating treatment for ENB cannot be overemphasized.

Treatment of Esthesioneuroblastoma

Classic treatment strategies of ENB are based on surgery or radiotherapy as unique modalities or a combination of surgery and radiation therapy. Most institutions favor surgery as the first treatment modality, followed by postoperative irradiation.

For ENB, a preoperative ophthalmology evaluation is mandatory because the optic nerves are at risk during either radical surgery or radiation. In a palate resection, the upper dental prosthesis will be made before surgery and put in place at the end of the procedure. This usually achieves separation of the oral cavity from the nasal cavity and allows adequate oral nutrition. Adjustments of this prosthesis are required after ablation of the nasal packing and following tissue scarring and/or retraction that take place within six months from completion of treatment.

A craniofacial team, in which neurosurgeons form an essential part, usually manages ENB surgically. Most of the important complications after surgery concern the brain and calvarium; thus, close neurosurgical follow-up is necessary.

Surgical Care: The usual surgical treatment uses a combined cranio-facial resection. In this procedure, a neurosurgeon makes an incision into the skull (craniotomy), while a head and neck surgeon makes and incision along the side of the nose (lateral rhinotomy). For select small tumors, surgeons can feed a small flexible instrument called an endoscope through the nose to remove the cancer. This is called the transnasal endoscopic approach. Surgeons treat metastatic tumors to the neck and parotid gland by removing the affected tissue (parotidectomy).

Postoperative activity: Patients usually are out of bed on the first postoperative day. When a lumbar drain remains postoperatively, patients require strict bed rest as long as the drain remains in place.

Radiation Therapy: Radiation therapies may include intensity modulated radiation therapy (IMRT) and Gamma Knife radiosurgery. These technologies allow effective treatment of the cancer while limiting the amount of radiation to important normal tissues such as the eyes, optic nerves, brain, brain stem and spinal cord. This careful focus is particularly important for cancers such as esthesioneuroblastoma.