Precursor Lesions of the Vocal Cord: a Study on the Diagnostic Role of Histomorphology, Histometry and Ki-67 Proliferation.

The precise typing of precursor lesions of squamous cell carcinoma of vocal cord is of vital importance since it determines the line of therapy and prognosis. The aim of the present study is to evaluate the possible value of the types of dyskeratosis, histometry and cell proliferation rate in discriminating these lesions. The present retrospective study was based on 145 patients, classified according to the updated 2017 WHO system and included: Low-grade dysplasia (24 cases), high -grade dysplasia (53 cases), carcinoma insitu (33 cases) and microinvasive carcinomas (35 cases). Cell proliferation was assessed by immunoreactivity to Ki-67. For histometry and quantitation of Ki-67 proliferation rate, an image analysis system was used (Leica LAS, Wetzlar, Germany). Epithelial pearls (cell nests) were commonly observed in microinvasive carcinoma (82.9%) than high-grade dysplasia (5.9%). The median epithelial thickness, as well as, proliferation rate showed a significant increase according to the grade of the lesion. It is concluded that dyskeratosis pattern, histometry and Ki-67proliferation rate are valuable parameters to characterize precursor lesions. The presence of epithelial pearls, thickness > 450 μm and Ki-67 > 40% denote high risk lesions that require adequate excision and/or radiotherapy.