How do you miss a 6cm lung nodule on a chest xray?

[rcarver]

Hi!  This is very confusing for me because I work in x ray and I have a hard time believing that a nodule as large as 6 cm can be overlooked on a chest x ray.  My dad had a routine cxr in Sept '08 which was unremarkable.  He had a horse accident in Nov in which he broke the 10th and 11th rib on the right anterior side.  Naturally, this was painful, but in March, he started having a fever and bad cough.  The chest x ray showed pneumonia in the right lower lobe.  Doc gave him a Z pak and he came in for a f/u cxr on 4-15. (I actually did this cxr so I saw myself what looked like he still had pneumonia).  The cxr showed he still had pneumonia and also a small pleural effusion and CT was recommended.  Holy cow...the ct showed three lung masses in the RLL---the largest is almost 7CM....and 4 enlarged lymph nodes in the right hilar region.  Naturally this is highly suspicious for metastatic malignancy, but...how in the world do you not see a 6CM mass on a cxr?  I get if it was aroung 6mm...but 6 CM?  My dad doesn't have a spleen and I know with the broken rib that he was probably taking it easy on that side...I'm hoping and praying that the broken rib caused his right lung to get lazy, therefore setting up the pneumonia and his compromised immune system is just not efficient enough to help him heal in a month.  The radiologists I work with have gone over his films over and over with me and we just do not see any hint of shadow or anything in prev x rays.  Any ideas or opinions on this?

[NancyLynn60]

A related discussion, 6 cm in size was started.

[NancyLynn60]

A related discussion, What do you think? was started.

[Kamal S Saini, MD, MRCP (UK), DM]

Great to hear this!!

[rcarver]

We got the results from the PET today...very faint uptake and smaller than on the CT.  No lymph nodes showed uptake...just residual pneumonia!

[Kamal S Saini, MD, MRCP (UK), DM]

Hi,
This is indeed unusual. A large lung lesion developed in the interval between an X ray and the subsequent confirmatory CT scan. Although a CT scan is much more sensitive than an X ray, but as you said, a large lesion should have been picked up by an X ray.
One possible explanation, as you have rightly deduced, is that he has a fulminant infection worsened by his asplenic state. The other could be an aggressive cancer.
At this time, a PET scan and a histopath (biopsy or FNAC) would provide vital information. Admission to a hospital and a course of intravenous antibiotics is strongly recommended pending further investigations.
All the best, and God Bless!