The patient underwent a bronchoscopy and biopsy, and histopathology with IHC evaluation confirmed poorly differentiated non-small cell lung carcinoma, adenocarcinoma subtype.

This case demonstrates the CT angiogram sign that refers to normally enhancing pulmonary vessels appearing prominent on contrast-enhanced CT as they traverse an airless portion of the atelectatic lung. The atelectatic lung is hyperattenuating to skeletal muscle whereas the tumour is relatively hypoattenuating.

The CT angiogram sign can be seen in post-obstructive atelectasis, pneumonia, pulmonary oedema and malignancies such as lung adenocarcinoma, pulmonary lymphoma, and metastasis from gastrointestinal carcinoma.