Clinicopathological features of minute pharyngeal lesions diagnosed by narrow-band imaging endoscopy and biopsy.

Aim: To evaluate the utility of magnified narrow-band imaging (NBI) endoscopy for diagnosing and treating minute pharyngeal neoplasia.

Methods: Magnified NBI gastrointestinal examinations were performed by the first author. A magnification hood was attached to the tip of the endoscope for quick focusing. Most of the examinations were performed under sedation. Magnified NBI examinations were performed for all of the pharyngeal lesions that had noticeable brownish areas under unmagnified NBI observation, and an intrapapillary capillary loop (IPCL) classification was made. A total of 93 consecutive pharyngeal lesions were diagnosed as IPCL type IV and were suspected to represent dysplasia. Sixty-two lesions of approximately 1 mm in diameter were biopsied in the clinic, and 17 lesions with larger diameters were resected by endoscopic submucosal dissection (ESD) at the Hiroshima University Hospital. In addition to the histological diagnoses, the lesion diameters were microscopically measured in 45 of the 62 biopsies. Thirty-four of the 62 biopsied patients received endoscopic follow up.

Results: Minute pharyngeal lesions were diagnosed in 93 of approximately 3000 patients receiving magnified NBI examinations at the clinic. Of the 93 patients with IPCL type IV lesions, 80 were men, and 13 were women. Fifty-six were drinkers, and 57 were smokers. Two had esophageal cancer. Twenty-one lesions were located on the posterior hypopharyngeal wall, and 72 lesions were located on the posterior oropharyngeal wall. All 93 lesions were flat and showed similar findings in the magnified and unmagnified NBI examinations. Although almost all of the IPCL type IV lesions showed faint redness when examined under white light, it was difficult to diagnose the lesions using only this technique because the contrast was weaker than that achieved in the NBI examinations. Of the 93 lesions, only 3 had diameters greater than 2.1 mm. Sixty-two lesions of approximately 1 mm were biopsied in the clinic, whereas 17 larger lesions were treated by ESD at the Hiroshima University Hospital. Of the 79 pharyngeal lesions that were biopsied or resected by ESD, 5 were histologically diagnosed as high-grade dysplasia, 39 were diagnosed as low-grade dysplasia, and 39 were determined to be non-dysplastic lesions. There were no cancerous lesions. Histologically, abnormal cell size variations and increased nuclear size were observed in all of the high-grade dysplasia lesions, while the incidence of these findings in the low-grade dysplasia lesions was low. Of the 62 biopsied lesions, 45 were microscopically measurable. The measured diameters ranged from 0.1 to 2.0 mm. The dysplasia ratios increased with the diameters. A follow-up endoscopic examination of the 34 biopsied patients found the rate of complete resection by biopsy to be 79%. The largest lesion in which complete resection was expected was a low-grade dysplasia of 1.9 mm in diameter.

Conclusion: Minute pharyngeal lesions suspected to be dysplasia that are identified by NBI magnifying endoscopy should be biopsied to determine the diagnosis and further treatment.