Shadow cell basal cell carcinoma with acantholysis.

I present histologic documentation of a unique basal cell carcinoma (BCC) in which shadow cells formed the major cellular component along with extensive acantholysis and the development of ringed shadow cells. This neoplasm contained trichohyalin granules, which are indisputable evidence of follicular differentiation. Shadow cells rarely are encountered within BCCs and generally form relatively small components. Such neoplasms have been labeled BCC with matrical differentiation. Because of nonspecificity and ambiguity, I propose that this terminology be abandoned and replaced by shadow cell BCC.