Endocrine Abstracts

Olfactory neuroblastoma (ONB) is a rare neuroendocrine tumour with a slow onset of symptoms, and classically a propensity for recurrence and a poor prognosis. Due to its rarity, there is no agreed standard therapy, but treatment will usually include surgical resection, adjuvant radiotherapy and/or chemotherapy. However, such tumours very often show positive uptake on somatostatin receptor radionuclide scanning, and selective use of peptide receptor radionuclide therapy (PRRT) has been described in case reports, but currently only a handful of cases have been reported, with varying results. We describe a case of ONB where PRRT is planned in a patient with ONB. A 41-year-old lady presented with loss of sense of smell and right-sided facial swelling. She was diagnosed with nasal polyps and was planned for surgical resection, but this was delayed due to the COVID-19 pandemic. She subsequently developed an abscess on the right side of her face and was treated with drainage and antibiotics. It was then noted on CT scanning that she had a solid mass around her right maxilla that on biopsy was demonstrated to be an olfactory neuroblastoma. She underwent surgical resection followed by adjuvant external beam radiotherapy and cisplatin chemotherapy. Two years later she developed disease recurrence, biopsy confirming a recurrent ONB (Ki-67 40%-70%), with extensive infiltration of the right ethmoid sinus and septum, perineural and lymphovascular invasion, and involvement of 5 lymph nodes. A 68Gallium-DOTATATE PET/CT showed intense uptake in all the involved areas and following further debulking she is planned for PRRT with 177Lu-dotatate. The extensive expression of somatostatin receptors (SSTR) in patients with ONB supports the use of SSTR-dependent therapies, such as PRRT, which has shown excellent results in improving progression-free survival in other neuroendocrine tumours. Prospective studies evaluating PRRT efficacy, toxicity and quality of life in this rare cancer population are needed.