Fig. 4

False positive result on two consecutive PET-CTs. On the PET-CT 3 months after the end of treatment, the area of the previous primary tumor around the right laryngeal ventricle showed a focal mild radiotracer uptake of SUV_max 3.2 (a). The laryngoscopy revealed a small bump on the anterior vocal cord, which revealed only mild chronic inflammation on biopsy. The PET-CT was repeated 9 months later because of hoarseness and an infectious-looking lesion on the false cord. Focal uptake on the previously detected uptake area had increased to 4.1 (b). On laryngoscopy, the false cord appeared exophytic, and biopsies showed epithelial hyperkeratosis and hyperplasia. Two and half years later (three and half years after end of treatment), the patient returned with a right-sided glottic tumor growth with biopsies resulting in SCC. CT (c) showed a malignant-looking enhancing lesion with ulceration on the anterior commissure, and anterior and middle thirds of the vocal cord