What is ground glass opacity on the lung? Is it likely to be cancer and how do you determine whether it is or not?

“Not everything that arises in the lung is cancer,” says Russell K. Hales, M.D., a radiation oncologist, at the Johns Hopkins Kimmel Cancer Center on the Johns Hopkins Bayview campus. “A nodule in the lung can be from infection, irritation, or inflammation. It can be from other diseases, unrelated to cancer at all.”

Hales notes that a ground glass opacity is a radiologist's characterization of how something may look on the scan. “It’s almost as if you were to describe a car as a red car. Well, that tells us it's red, but it doesn't tell us what type of car it is,” he says. Many factors go into determining how likely the opacity is to be cancer, including the size of the lesion, or whether it's growing.

“At the Hopkins Kimmel Cancer Center, we evaluate carefully whether a ground glass opacity is cancerous or not,” Hales notes. “We have a solitary pulmonary nodule clinic to evaluate patients with ground glass opacities. If you're a patient who was recently told you have something like this, you can certainly call 410-955-LUNG, so that we can specifically evaluate the ground glass opacity that you may have.”