Primary nasal-ethmoid choriocarcinoma detected by 18F-FDG PET/CT: a rare tumor with complete remission.

Choriocarcinoma is a highly malignant and rare tumor characterized by secretion of the beta-subunit-of-humanchoriogonadotropin (β-HCG). We report a case of primary nasal choriocarcinoma with good response to chemotherapy. A 36-years-old woman gravida 0 and with history of 4 spontaneous abortion, in December 2018 referred to Otorhinolaryngology Department for repeated episodes of epistaxis. Cervical Magnetic Resonance Imaging (MRI) revealed a tumor mass involving right nasal cavity, right ethmoid, sphenoidal and maxillary sinuses. For a differential diagnosis between metastatic gestational choriocarcinoma and primary choriocarcinoma in January 2019 she underwent 18Fluorine-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG-PET/CT) scan that demonstrated intense uptake only in the nasal-ethmoid tumor mass showed by MRI. This was suggestive of primary nasal-ethmoid choriocarcinoma she received 3 courses of BEP - regimen and after β-HCG was reduced to 500 mIU/mL and 18F-FDG-PET/CT scan showed a decreased uptake in tumor mass but the appearance of a new uptake in cervical lymph node which was analysed and reported as metastatic localization of choriocarcinoma. Therefore she was treated with 2 cycles of TIP-regimen. Subsequents 18F-FDG-PET/CT and MRI showed a complete tumor remission. This case proved the fundamental role of PET/CT to make diagnosis of primitive choriocarcinoma and to exclude the hypothesis of distant metastasis.