[Bowenoid basocellular carcinomas (basaliomas with cellular monstrosities]

Marked cellular atypia was detected in 4 out of 2,000 consecutive specimens of basal cell carcinoma. The lesions occurred on the exposed skin of the head of 4 male patients with ages between 49 and 71 years. Besides the general pattern of basal cell carcinoma and cellular atypia there were remarkable differences from lesion to lesion resulting in variable difficulties of differential diagnosis, not only with Bowen's disease (3 cases) but with Darier's metatypical epithelioma as well, either of the mixed or intermediate type (1 case each). As with the other cases reported in the literature, the presence of cell atypia did not correlate with a more aggressive clinical behaviour of the lesions.