A 34 year old female patient with a history of maternal grandfather who died of lung carcinoma. Sinusitis seven years earlier. She consulted her ENT specialist for a clinical history of 14 months with rapidly progressive rhinorrhoea and epistaxis. Rhinoscopy revealed a mass in the right nostril with a polypoid appearance, very bloody on contact, which occupied the entire right nostril and appeared to connect with the septum and middle turbinate, extending to the choana and occupying the nasopharynx. The biopsy was positive for stesioneuroblastoma.
A CT scan of the head and neck showed a 4-centimetre (cm) polypoid mass with a large pedicle in the right nostril and cavum. The MRI of the head and neck showed a space-occupying lesion that conspicuously obliterated the cavum and extended from the level of the nostrils towards the back, coming into contact with the prevertebral musculature, without infiltrating it, and well delimited.

A CT scan of the thorax and a bone scan without pathology are performed as an extension study. She was classified as Kadish Stage C.
She underwent functional endoscopic surgery and the pathological anatomy showed stesioneuroblastoma. The postoperative CT scan showed a polypoid thickening of the mucosa in the right maxillary sinus, with no evidence of malignancy, at the level of the right frontal sinus.

Adjuvant treatment with external radiotherapy was decided, using a Linear Accelerator with 6 and 15 MV photons, with tissue compensation wedges after virtual simulation and 3D planning on individualised helical CT. The tumour bed received a global dose of 60 Gy in 30 fractions, with a schedule of 2 Gy/fraction, 5 fractions per week. Tolerance was good, with maximum cutaneous G1, mucosal G2 and oropharyngeal G2 toxicity. Currently, 6 months after irradiation, the complete response has been maintained.