The immunopathology of regression in keratoacanthoma
Fathia A Bayoumi
Medcare Hospital, UAE
: Androl Gynecol: Curr Res
Abstract
Background: Keratoacanthoma (KA) has a tendency for either progression or spontaneous regression. Regression is a phenomenon present in a variety of cutaneous lesions. It is likely that certain immunologic mechanisms explain the phenomenon of spontaneous regression occurring in KA. Causes and detailed mechanism of this regression are still not completely elucidated. Recent studies suggested that the tumor regression is dependent mainly on the stromal immune response. Aim: As a first step in confirming or refuting this hypothesis, we did an immunohistochemical study of KA. Also, we correlated between the tumor size, rate of proliferation and stromal infiltration by cytotoxic T lymphocytes which release granzyme-B. Methods & Results: This is a case series study done on 20 cases of KA that were examined and clinicopathological findings were reviewed. Immunohistochemical stains using PCNA, P53 and granzyme-B were done. PCNA showed positive staining in all cases (100%) with significant positive correlation with the tumor size (0.5, p<0.02). P53 was positive in 16 cases (80%) with highly significant positive correlation with the tumor size (0.63, p<0.0028). Granzyme-B was positive in the stromal lymphocytes and histiocytes only in 6 cases (30%) with highly significant negative correlation with the tumor size (-0.79, p<0.0001). Negative correlation between PCNA overall score and granzyme-B was evident (-0.37) and between P53 overall score and granzyme-B also (-0.38). The mean total score for granzyme-B was higher (1.04+0.23) in tumors less than 1 cm in size if compared with that in tumors more that 1cm in size (0.66+0.12). Conclusion: The increased release and/or activity of granzyme-B as CTL-mediated response were a central effector mechanism in tumor regression in KA.
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