Basal cell carcinoma of the skin with areas of squamous cell carcinoma: Basosquamous cell carcinoma?

The diagnosis of basosquamous cell carcinoma is controversial.A review of cases of basal cell carcinoma showed 23 cases that had conspicuous areas of squamous cell carcinoma.This was distinguished from squamous differentiation and keratotic basal cell carcinoma by a comparative study of 40 cases of compact lobular and 40 cases of keratotic basal cell carcinoma.Areas of intermediate tumour differentiation between basal cell and squamous cell carcinoma were found.Basal cell carcinomas with areas of squamous cell carcinoma may be called baso- squamous carcinoma.Basal cell carcinomas have been described with nuc- lear atypia,' multinucleate tumour giant cells,' 2 and other unusual or aggressive features.3Only one case of basal cell carcinoma with areas of squamous cell carcinoma has been reported, and this was termed basosquamous cell carcinoma.4This controversial diagnosis is accepted by some authors-8 and rejected by others.9-'2This paper reports a his- topathological study of 23 cases of basal cell carcinoma of skin in which there were conspicuous areas of squamous cell carcinoma.