Squamous cell hyperplasia of the larynx (a clinical follow-up study).

According to Kleinsasser's classification 200 patients with squamous cell hyperplasia, seen between 1963-1981, were reviewed histologically. The untreated patients (47 per cent) have been analysed for the incidence of malignant change and the patients with Class III lesions (carcinoma in situ) who were treated, were analysed for response to treatment. The mean follow-up period was 8.4 years. Only two of the 38 initially untreated patients of Class I (simple squamous cell hyperplasia) developed an invasive carcinoma. In Class II (hyperplasia with atypia), of 62 patients who were not treated initially, 17 developed a laryngeal squamous cell carcinoma later. Only six patients of Class III did not receive any treatment initially, and one of these progressed to invasive carcinoma. Almost all other patients with carcinoma in situ (Class III) were irradiated. In these patients no evidence of local recurrence was found.