A red nodule of recent onset

A 79-year-old woman with extensive mottled sun-damaged skin had a prior history of multiple skin cancers. She noticed the recent appearance of an asymptomatic firm, red nodule (measuring 0.8 cm in diameter) on her forearm (Figure 1). Excision biopsy showed a normal epidermis under which there were sheets of atypical large cells with focally vacuolated cytoplasm and increased mitoses (Figure 2). Some of the cells were multinucleate.