Clinicopathological characteristics of abnormal micro-lesions at the oro-hypopharynx detected by a magnifying narrow band imaging system

Background: Narrow band imaging (NBI) with magnifying endoscopy (NBI-ME) allows the detection of abnormal micro-lesions smaller than 5 mm in diameter in the oro-hypopharynx that could not be visualized previously. The purpose of the present study was to clarify the clinicopathological characteristics of abnormal micro-lesions of the oro-hypopharynx detected by NBI-ME Methods: Of the 62 lesions detected by NBI-ME, 40 abnormal micro-lesions in 37 patients were removed by endoscopic treatment and were pathologically evaluated. We reviewed the medical records of patients with these lesions and investigated the relationship between NBI-ME findings and pathological findings. Results: Pathological examination revealed the following: high-grade intraepithelial neoplasia (HGIN) in nine (23%) lesions, low-grade intraepithelial neoplasia (LGIN) in 22 (55%), pharyngitis in seven (18%) and papilloma in two (5%). Two NBI-ME findings, high microvascular density (MVD) and a brownish area (BA), were recognized more frequently as the grade of malignancy advanced. The likelihood ratio (confidential interval) for having HGIN in the patients with both MVD and BA was 13 (3.62-127). Conclusions: The pathological diagnosis of abnormal micro-lesions ranged from pharyngitis to HGIN. High MVD and BA may be important findings for grading the malignancy of abnormal micro-lesions.