Lightmicroscopical features of interferon-alpha-treated laryngeal papillomatosis in adults.

Papillomatous tissue samples from 12 adult patients with laryngeal papillomatosis were examined by light microscopy before and after interferon-alpha (IFN) treatment. Increased atypia, a change in intra-epithelial differentiation, sclerosis of the underlying stroma and infiltration of especially plasma cells were found in tumour tissue removed after 3 weeks of IFN treatment. These morphological findings do not explain the effects exerted by IFN on the growth pattern of adult laryngeal papillomatosis, but provide a basis for further studies.