The purpose of this study was to evaluate the usefulness of thallium-201-chloride (Tl-201) scintigraphy for the examination of patients with tumors of the head and neck, and to estimate the correlation of the expression of Na⁺/K⁺-ATPase with Tl-201 scintigraphy. Tl-201 scintigraphy was performed in 61 patients with squamous cell carcinoma and 10 patients with benign tumors of the salivary gland. The tumor retention index was obtained from the early and delayed dynamic Tl-201 scintigraphies. The expression of Na⁺/K⁺-ATPase on the cell membrane was evaluated immunohistochemically. Evaluation of correlations between the histopathological tissue differentiation of tumors, the tumor retention index of Tl-201 scintigraphy and the expression of Na⁺/K⁺-ATPase was performed. The tumor retention index of Tl-201 scintigraphy correlated well with the histopathological tissue differentiation of tumors and also showed a good correlation with the expression of Na⁺/K⁺-ATPase. In addition, the expression of Na⁺/K⁺-ATPase demonstrated a close correlation with the histopathological tissue differentiation of malignant tumors. The tumor retention index could be used for the differentiation of malignant tumors from benign tumors and the expression of Na⁺/K⁺-ATPase was estimated as one of the most important factors for Tl-201 accumulation in malignant tumors.

Background/Aims: Image-enhanced endoscopy can detect superficial oro-hypopharyngeal squamous cell carcinoma; however, reliable endoscopy of the pharyngeal region is challenging. Endoscopy under general anesthesia during transoral surgery occasionally reveals multiple synchronous lesions that remained undetected on preoperative endoscopy. Therefore, we aimed to determine the lesion detection capability of endoscopy under general anesthesia for superficial oro-hypopharyngeal squamous cell carcinoma. Methods: This retrospective study included 63 patients who underwent transoral surgery for superficial oropharyngeal squamous cell carcinoma between April 2005 and December 2020. The primary endpoint was to compare the lesion detection capabilities of preoperative endoscopy and endoscopy under general anesthesia. Other endpoints included the comparison of clinicopathological findings between lesions detected using preoperative endoscopy and those newly detected using endoscopy under general anesthesia. Results: Fifty-eight patients (85 lesions) were analyzed. The mean number of lesions per patient detected was 1.17 for preoperative endoscopy and 1.47 for endoscopy under general anesthesia. Endoscopy under general anesthesia helped detect more lesions than preoperative endoscopy did (p<0.001). The lesions that were newly detected on endoscopy under general anesthesia were small and characterized by few changes in color and surface ruggedness. Conclusions Endoscopy under general anesthesia for superficial squamous cell carcinoma is helpful for detecting multiple synchronous lesions.