Atypical mitotic figures in basal cell carcinoma. A review of 208 cases.

A retrospective review of 208 cases of basal cell carcinoma (BCC) from the Johnson City Veterans Affairs Medical Center (VAMC) and University Physician's Practice Group Clinic was made to ascertain the percentage of BCCs having mitoses and to evaluate the possible occurrence of abnormal mitotic figures. One of the authors had observed in a limited cytologic sample that the detection of atypical mitotic figures in a lesion suspected of being a BCC could be a helpful indicator pointing toward a nonbasal cell carcinoma diagnosis. The present study demonstrated abnormal-appearing mitotic figures in 121 of 208 cases. However, definite tripolar or tetrapolar forms were present in only a small number of cases. Thus, the presence of these forms in an "equivocal" basal cell carcinoma may suggest an alternate diagnosis but does not totally exclude a diagnosis of BCC.