Background: A wide spectrum of lesions ranging from dysplasia to in situ carcinoma have to be considered when dealing with laryngeal precancerous conditions. Recently the concept of laryngeal intraepithelial neoplasia (LIN) was introduced.
Methods: A series of 259 consecutive cases of laryngeal keratosis was studied from 1976 to 1994. All patients entered the study after microlaryngoscopy and biopsy. Histologic diagnoses were subdivided into keratosis without dysplasia (KWD), with mild dysplasia (LIN 1), with moderate dysplasia (LIN 2), and with severe dysplasia or carcinoma in situ (LIN 3). The follow-up period ranged from 15 months to 19 years (mean, 101 months).
Results: KWD had the best prognosis with the lowest recurrence rate (12.5%) after stripping of laryngeal mucous membrane. The recurrence rate after stripping was higher for LIN 1 (25%) and LIN 2 cases (68.7%). The recurrence rate after CO2 laser cordectomy was 16.6% for LIN 2 and 18.7% for LIN 3. The incidence of progression to infiltrative carcinoma was 4.19% for KWD, 7.14% for LIN 1, 21.42% for LIN 2, and 9.37% for LIN 3.
Conclusions: KWD and LIN 1 can be successfully treated by stripping the mucous membrane, close follow-up, and a change in smoking habits. On the contrary, LIN 2 and LIN 3 need a more aggressive therapeutical approach.