INTRODUCTION: Laryngeal dysplasias, precursors of squamous cell carcinomas, are uncommon lesions, inasmuch as most cases are diagnosed as invasive carcinomas. OBJECTIVE: To characterize severe dysplasia/in situ carcinoma of the vocal cords by comparing the area of involved epithelium, nuclear diameter, and proliferative index with transition and normal squamous epithelia. MATERIAL AND METHOD: Among 1,400 surgical and biopsy specimens of laryngeal lesions (1994-2006), five cases (0.35%) were selected and compared according to age with two controls with normal epithelium. Furthermore, all of them were identified and submitted to morphometric and immunohistochemical analysis (Ki-67). RESULTS: After comparing dysplastic with transition and normal squamous epithelia, it was observed an increased nuclear diameter in dysplastic epithelium. Additionally, there was no significant difference in nuclear diameter per layer between dysplastic and transition epithelia. Moreover, the proliferative index was higher in dysplastic epithelium with stained nuclei in all layers and lower in normal and transition epithelia with nuclei concentrated on the basal and parabasal layers. CONCLUSION: Dysplastic epithelium occupies larger areas. Nuclear diameter is similar in dysplastic and transition epithelia. However, the latter has uniform nuclei, in contrast with pleomorphism in dysplastic epithelium. The proliferative index (Ki-67) contributes to the differential diagnosis of intraepithelial lesions of the vocal cords, inasmuch as in severe dysplasia/in situ carcinoma there is a higher number of stained nuclei, which are seen in all epithelial layers.
Larynx; Carcinoma in situ; Vocal cord; Ki-67 antigen
