Reference for Chullin 110:7

ולית הלכתא כרב עוירא (דרב עוירא נמי) לא אמרן אלא בקולשיה אבל בסומכיה טרפה ואי אישתייר ביה כעובי דינר זהב כשרה

It was said in the West: Whatsoever is considered a defect in the lung is not a defect in the kidney, for a perforation is a defect in the lung and is not a defect in the kidney; and of course, whatsoever is not considered a defect in the lung is not a defect in the kidney.

Jastrow