Question: Hi, I had a CTA to check the status of a PE I was diagnosed with in October 2018. There were no nodules in the tests done in October 2018 or January 2019. Do the results below from the test I had last week mean that there are now 2 nodules, one pleura-based 8mm nodule that goes into the right lung and another nodule in the left lower lobe?
How concerned should I be about the % of the pleura-based nodule being malignant? What I've found on the internet so far states that pleura-based nodules are almost always metastasized from somewhere else in the body and malignant.

How can it be a stable pleural-based nodule if there were none as recently as January?
Would your opinion also be that I should request a PET scan as the next diagnostic tool or something else?



FINDINGS:
Pulmonary Arteries: The study is of adequate diagnostic quality due to patient's increased body habitus and borderline GFR. There are no filling defects in the main, lobar and segmental branches. The subsegmental branches are not well opacified . The pulmonary arteries are normal in size.

Aorta: The aorta is nonaneurysmal. Aberrant right subclavian artery.
Heart: The heart size is normal. There is no pericardial effusion.
Mediastinum and hila: There is no mediastinal lymphadenopathy. There is no hilar lymphadenopathy. The thoracic esophagus is normal.
Axilla: There is no axillary lymphadenopathy.
Thyroid gland: Negative.
Lungs: Stable pleural-based nodule in the right lower lobe measuring up to 8 mm seen on axial lung window right intrafissural nodule. Left intrafissural nodule. Image 52.
Bones: There is no rib fracture. There are no bony lytic or osteoblastic lesions.

Upper Abdomen: There is no retrocrural lymphadenopathy. There are no masses in the liver, spleen, pancreas, or the adrenal glands.

IMPRESSION:
No definite central, lobar or segmental pulmonary embolism. Subsegmental branches are not well evaluated due to patient's increased body habitus/suboptimal bolus.

Stable pleural-based nodule in the right lower lobe.

I have read that pleura based nodules don't originate there but are metastasized from elsewhere in the body. Is it possible that these have mets from the lungs or likely elsewhere?