The most frequent consideration in the clinical and histologic dif ferential diagnosis of keratoacanthoma is squamous cell carcinoma. In
the pres ent study, cytokeratin 10 ex pres sion and pro lif er a tion rate as measured by Ki-67 ex pres sion were com pared be tween 50 clin i cally and histologically di ag nosed keratoacanthomas and 50 squamous cell car ci no mas.
Tis sue sec tions from the skin were immunohistochemically stained with
anti-cytokeratin 10 and anti-Ki-67 monoclonal antibodies. The distribution of
cytokeratin 10 ex pres sion and proliferative cell count were analyzed. Study
results showed higher cytokeratin 10 expression in kerato acanthomas than
in squamous cell car cinomas and different distribution of staining in the two
entities. The analysis of cytokeratin 10 ex pression showed a much wider
range of values and statistically higher median (p 0.001) in kerato acanthomas than in squamous cell carcinomas. Additionally, the prolifer ation index of keratinocytes as mea sured by Ki-67 ex pres sion was significantly higher
in squamous cell carcinomas than in keratoacanthomas (p 0.01). These
re sults may prove help ful in histologic differentiation of these disorders
