19) Metatypical BCC has been used synonymously with basosquamous carcinoma by some authors (6,18-19) and by others, it is used to describe tumors that have overlapping features of both squamous and basal cell carcinomas, (20) which is how the term is used at our institution.
Metatypical basal cell carcinoma: a clinical review.
The histopathology of the skin basal cell carcinoma with areas of intermediate differentiation: a metatypical carcinoma?
The pathologic presence of multiple different neoplasms coexisting in a single cancer lesion can result either from (1) a collision tumor, in which two or more cutaneous malignancies coincidentally collide and clinically appear as one lesion (46) or (2) a metatypical
tumor, in which the epidermal keratinocytes differentiate into tumor cells of both basal cell carcinoma and squamous cell carcinoma, such as a basosquamous (or basaloid squamous cell) carcinoma.
or basosquamous carcinoma is a subtype that is characterized by varying degrees of squamous differentiation.