Fluorescence diagnosis in keratinocytic intraepidermal neoplasias.

<bold>Background: </bold>As different tissue types have distinct capabilities to accumulate protoporphyrin-IX, fluorescence diagnosis with aminolevulinic acid-induced porphyrin (FDAP) could be used to discriminate between different tissue types.<bold>Objective: </bold>Protoporphyrin-IX accumulation and proliferation were studied in cutaneous squamous (pre)malignancies to see whether FDAP could be used to discriminate between different stages of keratinocytic intraepidermal neoplasia or proliferative status.<bold>Methods: </bold>FDAP was performed in 14 patients (86 lesions) and biopsy specimens were taken, on which (immuno)histochemistry was performed for histopathologic classification and assessment of Ki67-antigen expression. Stratum corneum thickness was also measured.<bold>Results: </bold>The fluorescence ratio (lesional:nonlesional skin) showed neither significant differences between the different keratinocytic intraepidermal neoplasia stages, nor between different levels of Ki67-antigen expression. Macroscopic fluorescence intensity and stratum corneum thickness were negatively correlated.<bold>Limitations: </bold>Relatively few malignancies were biopsied.<bold>Conclusions: </bold>With FDAP we were not able to discriminate between keratinocytic intraepidermal neoplasia lesions or proliferative activity. However, hyperkeratosis appeared to be an important determinant in variations in macroscopic fluorescence intensity. [ABSTRACT FROM AUTHOR]