Diffuse coexpression of thyroid transcription factor-1 and p40 in a non-small cell carcinoma of the lung: Second case in the female population.

Some non-small cell carcinomas of the lung can express TTF1 and p40 in the same tumor cells. This event has been described in only six cases prior to this one, and only in one other female. It is an extraordinary event that appears as a new entity yet to be defined. The case presented is a woman with a non-small cell lung carcinoma with diffuse coexpression of TTF1 and p40 in the same cells.