Clinical history: 73 year old male presented with a right lower lobe lung mass. Right lower lobectomy was done and 1.8 x 1.5 x 0.9 cm lobulated lesion with a white and yellow cut surface was noted and sampled.
What is the most probable diagnosis?
Sections of tumour show biphasic morphology of moderately differentiated squamous cell carcinoma and well differentiated adenocarcinoma with focal clear cell features. The proportion of adenocarcinoma and squamous cell carcinoma is approximately equal.
The immunostains performed show reactivity for TTF-1, CK7 in the adenocarcinoma component and p63 and CK5/6 show diffuse reactivity in the squamous differentiation areas. The findings confirm the diagnosis of adenosquamous carcinoma.