Thread by @MdSuster

1) Nice illustrative example on a common issue in lung biopsy interpretation. Lung cancers are notorious for presenting with a mixture of patterns as well as invasive and non-invasive components that can make for pitfalls on sampling.

#pathtwitter #pulmpath @smlungpathguy

2) Here is an axial HRCT scan from a lesion - it shows two components - periphery of "ground glass" and a central denser area with a little bit of enhancement.

3) Now imagine two separate biopsies from this tumor; one where the needle is placed in the periphery, and one that snags that central component- likely to turn up pretty different findings.

4) Here is a case where they hit the interface (Kudos!). A- corresponds to ground glass area and histologically shows a "lepidic" pattern.
B- corresponds to the central solid component and shows an invasive pattern (micropapillary and acinar IMO)

5) Here are higher power magnifications of A and B. Now you can understand the reasoning why you can essentially never sign out a "lepidic" adenocarcinoma on biopsy, since you don't know with certainty what may be lurking in the rest of the tumor!

Bonus image: This tumor also had the so called "Filigree" micropapillary pattern present.

PS I post 99% of my images free of tags ETC on twitter so anyone can use them. Please don't steal these particular ones - they are already going into a publication and hence already copyrighted (not by me). thank you :)