If left untreated, 10%-62% of patients with esthesioneuroblastoma may progress to develop metastasis. Common complications of esthesioneuroblastoma include tumor recurrence and metastasis. These tumors often display varying biologic activity ranging from indolent growth, with patient survival exceeding 20 years, to a highly aggressive neoplasm capable of rapid widespread metastasis, with survival limited to a few months. The five-year mortality rate of patients with esthesioneuroblastoma is approximately 56% and 20% for grade I and II and grade III and IV tumors, respectively. The ten-year mortality rate of patients with esthesioneuroblastoma is approximately 67% and 34% for grade I and II and grade III and IV tumors, respectively.^[1][2]

Esthesioneuroblastoma tumors display varying clinical behaviors ranging from indolent growth to highly aggressive invasion.^[1] The average delay between the appearance of the initial symptom and the diagnosis is six months, however diagnosis may be delayed for years in some cases. The delay is predictable because initial symptoms tend to be subtle and are frequently common, occurring also in nasal diseases, including allergic polypoid sinus disease or long-term rhinosinusitis.^[3] Clinical presentation is usually secondary to nasal stuffiness and rhinorrhea or epistaxis. Presentation is often delayed and symptoms may have been present for many months. Patients often present late with larger tumors which can extend into the intracranial compartment (25-30% at diagnosis) and usually result in anosmia. Despite aggressive therapy, esthesioneuroblastoma has been noted to have a high local recurrence rate of approximately 50–60% with 10–62% presenting as metastatic cases and 20–30% of those cases involving the CNS. Once esthesioneuroblastoma cells invade the cribriform plate, they may spread to the anterior skull base, extend to the leptomeninges or brain parenchyma and can lead to drop metastasis anywhere in central neural axis.^[2] Retropharyngeal lymph nodes are at risk for metastatic disease, however level II lymph nodes are most frequently involved.^[4] Cervical and retropharyngeal nodal metastases are present in 10-44% of cases at diagnosis.^[5]

• Tumor recurrence
• Metastasis^[2]

• The majority of studies have found a correlation between Hyams grade and prognosis.^[6][7][8][9]
• The prognosis depends on the magnitude of the disease on initial diagnosis.
• Esthesioneuroblastomas often display varying biologic activity ranging from indolent growth, with patient survival exceeding twenty years, to a highly aggressive neoplasm capable of rapid widespread metastasis, with survival limited to a few months.
• CNS metastasis is reported to have a survival expectancy of two years or less and is usually noted 0–10 years after the initial diagnosis.
• Spinal metastasis of esthesioneuroblastoma is rare with only 28 documented cases involving the spine, spinal cord, or leptomeninges.^[10]
• The metastatic rate of esthesioneuroblastoma has been estimated to range from 10 to 62 percent. The most common site of metastatic disease is the cervical lymph nodes but metastatic disease has been found in the parotid, long bones, meninges, breast, lung, prostate, abdominal viscera, and pelvis.
• The rate of local recurrence for this tumor after therapy is 57% with a survival rate of 56% at the end of five years.
• Prognostic factors must be considered when determining the best treatment for esthesioneuroblasstoma. Murakami et al. reported that histological tumor grade and complete surgical resection are the two most important prognostic factors. Hwang et al. emphasized the importance of diagnosing the disease in an early stage and regular radiologic followups to detect disease recurrence, to improve prognosis.^[2]

The relationship between grade of the tumor and ten-year survival is shown below in a tabular form:

The relationshiip between grade of the tumor and five-year survival is shown below in a tabular form:^[9]

The relationship between metastasis and five-year survival of the tumor is shown below in a tabular form:^[5]