Olfactory neuroblastoma following treatment for pituitary adenoma.

Olfactory neuroblastoma is extremely rare as a second neoplasm. We report an unusual case of olfactory neuroblastoma in a 59-year-old woman who had undergone two operations and received 54 Gy of irradiation for pituitary adenoma 20 years ago. At the time of admission, the patient presented with nasal obstruction and frequent epistaxis. Imaging studies showed a large mass in the nasal cavities and ethmoid sinus, extending to the intracranial area, with no evidence of any recurrence of the previous pituitary adenoma. The tumor was completely excised via a trans-cranial and trans-nasal approach. A diagnosis of olfactory neuroblastoma was established, and the patient was given postoperative chemotherapy. Although relatively uncommon, second neoplasms are an important consideration in the differential diagnosis of patients with new or recurring symptoms after treatment for pituitary adenoma. Furthermore, it is likely that radiation played a critical role in the development of olfactory neuroblastoma in our patient.