Comparative analysis of squamous cell differentiation by histologic subtypes in basal cell carcinoma

Background: There has been no general agreement on classifying basal cell carcinoma (BCC), and little is known about the squamous cell differentiations of each subtype of BCC. BCC is a locally-invasive tumor, but its aggressive forms tend to recur and metastasize. Objective: We have compared the histolopathological subtypes of BCC by squamous differentiation, with special emphasis on basosquamous carcinoma and the difference between the non-aggressive and aggressive forms of BCC. Materials & method: A total of 87 BCC specimens were collected from the 7 branch hospitals of The Catholic University of Korea from July 1997 to June 2003. Results: 1. The 87 samples were divided into 6 subtypes: 18 nodular, 19 nodular infiltrative, 12 micronodular, 14 infiltrative, 11 morpheaform, 13 basosquamous. Overall, 18 samples were classified as non-aggressive and the remaining 69 as aggressive. 2. In nodular-infiltrative BCC and basosquamous carcinoma, squamous cell differentiation was significantly more prominent than in the nodular BCC. Conclusion: Squamous cell differentiation should be considered as one of the aggressive markers, especially in nodule-forming BCC.