PMC5660802_01
Endoscopic findings of palatine tonsils. The lesion could not be clearly visualized using conventional endoscopy ((a) right tonsil; (c) left tonsil). NBI enhanced an irregular surface and abnormal vascular proliferation ((b) right tonsil; (d) left tonsil).
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We sought the primary lesion throughout the pharynx; a small granular lesion on the right tonsil and a tiny mass on the left tonsillar pillar were recognized using transoral endoscopic examination with NBI (Figure 1).
CT scan with contrast enhancement ((a) axial view; (b) coronal view). A CT scan demonstrated a cystic mass on the left side of the neck; however, tonsillar tumors were not detected.
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However, the tonsillar tumors were not detected (Figure 2).
PET/CT scan ((a) axial view; (b) coronal view). A PET/CT showed a high accumulation of fluorodeoxyglucose (FDG) to the left neck mass, and there was a slight laterality of FDG accumulation in the tonsils with the right-side predominance. The tonsillar uptake of the FDG was within the physiological range, which was not conclusive for the diagnosis of the tonsillar primary lesion.
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However, the uptake of the FDG was within the physiological range (SUVmax = 5.6), which was not conclusive for the diagnosis of the tonsillar primary lesion (Figure 3).
Histopathological results ((a), (b), and (c) right side; (d), (e), and (f) left side). Histopathological analysis of the biopsied tonsillar specimen revealed poorly differentiated SCC ((a) and (d)). Immunohistochemical staining for p16 was strongly positive in both lesions ((b) and (e)). ISH was positive for high-risk HPV ((c) and (f)).
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A biopsy of the bilateral tonsils revealed poorly differentiated SCC that was shown to be HPV-related using immunohistochemistry for p16 and in situ hybridization (ISH) (Figure 4).