Adenocarcinoma, Pulmonary Primary

Today, we discussed a case of an elderly man with nearly 100-pack-year smoking history presenting with subacute progressive shortness of breath, found to have a an isolated elevated alkaline phosphatase on labs and a chest x-ray with an extensive bilateral reticular pattern. This was followed up by a CT chest with finding of extensive multifocal consolidative opacities as well as nodules in a perilymphatic distribution suspicious for lymphangetic tumor spread along with a liver mass.  

Ultimately, tissue was consistent with metastatic adenocarcinoma with lung primary.

Adenocarcinoma is a type of non-small cell lung cancer arising from the bronchi, bronchioles and alveolar cells. WHO subdivides into mucinous and non-mucinous variants.

Radiologically, adenocarcinomas usually appear as ground glass opacities or solid nodules/ mass lesions--often in the periphery or upper lobes. These imaging finding typically correspond to a lepidic pattern (neoplastic cells lining the alveolar lining) or invasive tumor, respectively.

Epidemiologically, as below, adenocarcinoma is the most likely diagnosis in this patient, given the relative frequency of lung cancer, and specifically adenocarcinomas--in conjunction with the patient's significant smoking history.

Also, adenocarcinoma represents the most common type of lung cancer in females, nonsmokers and younger males. Patients with these characteristics (rather than older smokers) are more likely to have mutations in EGFR, ALK, PD1, and ROS-1--and these molecular diagnostics can guide targeted therapy (tyrosine kinase inhibitors).