There are several variants of basal cell carcinoma, all of which tend to occur in areas of sun exposure:
Superficial basal cell carcinomas appear as a scaly plaque and might resemble psoriasis or eczema.
Nodular basal cell carcinomas appear as a slightly shiny or translucent nodule which may ulcerate centrally and have blood vessels visible on their surface.
Infiltrative (or morphoeic) basal cell carcinomas are less well-defined plaques and can be difficult to identify.