Olfactory Neuroblastomas Patterns of Metastases

Introduction: Olfactory neuroblastoma (ONB) is a rare anterior skull base tumor with a variable disease course. Metastases to the neck have been reported in approximately 20-25% of cases. This is replicated in our study of 33 cases from a large UK tertiary center. In addition to this, we report an unusually high proportion that metastasizes to the face, a pattern not previously described.

Background: ONBs were first described by the French physician Berger in 1924. They account for only 3-6% of malignant sinonasal tumors and less than 1% of all head and neck cancers. They arise from the olfactory neuroepithelium in the superior part of the nose and therefore frequently involve the cribiform plate and olfactory bulb area of the anterior cranial fossa. Prognosis is good, with a 5-year survival rate of nearly 80% with complete surgical resection. Local recurrence rates, however, are relatively high (approximately 30%), and multiple studies have demonstrated late neck metastases in approximately 20-25% of ONBs. Salvage surgery and radiotherapy are employed in such cases.

Method: A retrospective study was conducted on a large cohort of patients with sinonasal malignancies from a regional referral center for anterior skull base surgery in North West London. Pathology records and T data from 2002-2012 were used to identify all patients with ONB who attended Charing Cross Hospital during this period. Patient records, radiology, and histopathology were analyzed. Patterns of disease progression, treatment, and outcome were reviewed and compared with previous studies. Three cases of metastases to the face were of particular interest.

Results: Thirty-three patients with ONB presented to the unit from 2002-2012, 33% female and 67% male, at varying stages of disease. Eight (24%) of the patients metastasized to the neck and three (9%) to the cheek. These three cases were reviewed in more detail.

Case A: White man who presented at age 59 years with isolated sinonasal ONB. He underwent endoscopic excision followed by chemoradiotherapy. Six months after diagnosis he developed a metastatic facial lymph node (LN), which was treated initially with radiotherapy and then excised.

Case B: White man who underwent craniofacial resection of ONB followed by postoperative radiotherapy at the age of 51 years. This recurred 5 years later. Seven years after initial presentation, he developed a metastatic LN in the cheek partially surrounded by parotid tissue, which was treated with excision.

Case C: White woman who presented at age 46 years with advanced disease. She initially underwent chemoradiotherapy followed by craniofacial resection. She developed late LN metastases in the neck and cheek at 3 and 8 years, respectively.

The patients in cases B and C survived for more than 10 years after initial diagnosis despite recurrence and later evidence of facial metastases. Patient A remains disease free 4 years following initial treatment.

Conclusion: This study suggests that special attention be paid not only to the neck, but also the face, when assessing for ONB metastases. Long-term monitoring is required to identify recurrences as these can be treated with significant success rates if detected.