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The Korean Journal of Pathology 2000;34(2): 145-153.
Histological and Immunohistochemical Characteristics of Keratoacanthoma and Well Differentiated Squamous Cell Carcinoma.
Lucia Kim, Seung Kyung Hann, Kwang Gil Lee
1Departments of Pathology, Yonsei University College of Medicine, Seoul 120-752, Korea.
2Departments of Dermatology, Yonsei University College of Medicine, Seoul 120-752, Korea.
3Department of Pathology, Yonsei University Wonju College of Medicine.
ABSTRACT
Keratoacanthoma (KA) is a rapidly growing cutaneous tumor and is difficult to distinguish from squamous cell carcinoma (SCC) on histomorphology alone. In the present study, we compared the clinicopathological and immunohistochemical findings using antibodies for p21 (WAF-1/CIP1), p53, laminin, and Ki-67 proteins in 27 cases of KA and 31 cases of well differentiated SCC. KA was characterized by occurrence in sun-exposed skin, shorter duration, and smaller size. Expression of p21 protein was increased according to the maturation and involution of KA, but there was no statistical significance. Expression of Ki-67 was decreased in the involutional stage of KA than in SCC (p<0.05). But p53 protein and Ki-67 were expressed in the cells at the periphery of both KA and SCC. The immunoexpression pattern of p53 and Ki-67 suggests that proliferative activities of the two lesions are similar. Laminin was present in the infiltrative cell nests of fully developed and involutional stages of KA, and it may be related to the healing process of KA. In conclusion, it is suggested that the degree of proliferative activity in the proliferative and fully developed stages of KA is similar to that of SCC and that p21 gene expression represents the differentiation property of KA and may be associated with its regression.
Key Words: Keratoacanthoma; Squamous cell carcinoma; p21 (WAF-1/CIP1); p53; Ki-67; Laminin