[Solar keratosis: a histochemical study on the distribution of SH groups and SS bonds]

The distribution of free SH groups and SS covalent linkages in hypertrophic, atrophic, acantholytic, bowenoid, pigmented solar keratoses (SK) and squamous cell carcinoma was evaluated. The sulphydryl groups were present in cytoplasms with a granular pattern and nucleoli mainly in atrophic, hypertrophic and bowenoid SK; the distribution of SS linkages appeared as a brilliant ovoid fluorescence localized in living layers, due to individually keratinized cells in SK. Similar results were found in squamous cell carcinoma. Our results agree with the opinion which considers SK as in situ carcinomas.