ＦＤＧ‐ＰＥＴにより原発巣が判明した原発不明癌例

Abstract

18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is a powerful tool for the detection of malignant tumors. We herein reported a case of cervical metastasis from unknown primary. Primary tumor was successfully diagnosed by FDG-PET. A 70-year-old man presented with a right-sided cervical lymph node swelling. Fine needle aspiration cytology in the previous hospital showed class III atypia, however, the primary tumor was not found by physical examination, fiberscopy, computed tomography (CT), or magnetic resonance imaging. Open biopsy of the neck demonstrated that the lesion was metastatic squamous cell carcinoma, and he subsequently underwent neck dissection on the affected side. FDG-PET and PET/CT after surgery revealed demonstrated uptake in the right piriform recess of the hypopharynx. The patient was eventually referred to our department, and underwent biopsy of the piriform recess via direct endoscopy. Histopathological diagnosis was the poorly-differentiated squamous cell carcinoma, and then he received radical radiotherapy of 72Gy to the whole neck. There was no evidence of recurrence on FDG-PET performed four months after radiation. The literature on the clinical usefulness of FDG-PET for the diagnosis of head and neck cancers were reviewed.