Abstract :
Lung carcinoma is the most common and lethal malignancy in men. Non-small cell lung carcinoma is more
aggressive than small cell lung carcinoma and often presents in advanced stage with metastasis. Cytology,
histopathology, immunohistochemistry and metabolic imaging play an important role in classifying lung
carcinomas. TTF 1 and Napsin A are highly sensitive and specific for adenocarcinoma lung, but the
sensitivity and specificity decreases in high grade tumours. Elevated serum CA 19-9 tumour marker is
not always related to pancreatico-biliary adenocarcinomas. It can be positive in adenocarcinoma lung and
its elevation confers poor prognosis. Quintessential role of metabolic imaging like 18F-FDG PET CT scan
in high grade carcinomas is well known. With the advent of targeted therapy, molecular and receptor studies
of EGFR, ROS 1 and ALK gene rearrangement becomes mandatory in all lung adenocarcinomas. Hence,
both oncologist and pathologist should diagnose advanced stage tumours without bias with good clinical,
radiological and pathological correlation.
Keyword :
Lung adenocarcinoma, Immunohistochemistry, CA 19-9, TTF1, Napsin A, Metabolic imaging.