Fluorescence diagnosis in keratinocytic intraepidermal neoplasias.

Background: 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.

Objective: 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.

Methods: 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.

Results: 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.

Limitations: Relatively few malignancies were biopsied.

Conclusions: 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.