What is a 4 mm nodule with central lucency

what is a nonsmall cell lung carcinoma. that is what my mother has been diagnosed with. with the largest one in her left hilum of lower lung

Orly, I am assuming that the nodule was found in a lung, since you tagged your question with Lung tags. Is that right?

Can I ask you a couple of questions? How old are you, and why the doctor recommended a CT scan, and whether you are (or were in the past) a smoker? Some of the answers to those questions can help us give you better answers to your question.

But here's some info based on what you asked.

First of all, understand 4 mm. That stands for 4 millimeters, which is quite small. There are about 25.5 millimeters in an inch, so 4 mm is like 1/6 of an inch.

A nodule is a small, round growth on a lung that shows up as a spot on a scan. On a lung, it's called a pulmonary nodule. Some are benign -- harmless -- and some may be cancerous. Usually it is called a nodule if it is 3 mm or less, and larger than that it's called a mass.

Lucency refers to how the nodule shows up on a CT scan. Tissues have different levels of density and show up differently on a scan. Lucency represents an area of tissue that is different from the tissue around it because it shows up as a spot on the X-ray.

About 60 percent of pulmonary nodules turn out to be benign, and 40 percent turn out to be cancerous. If a pulmonary nodule is cancerous and is caught before it's 1 centimeter across, 80 percent of patients live 5 years or more. (One centimeter equals 10 mm, so a 4 mm nodule is not quite half that size).

If your doctor is concerned about this nodule, she or he has probably told you when to come back for another scan, in order to monitor the growth rate. If the nodule is benign, there will be little or no growth. If the nodule has expanded, they might biopsy it -- remove some cells with a long needle -- to study the cells.

Here's a University of Rochester Medical Center page on pulmonary nodules, their diagnoses and treatment:

http://www.urmc.rochester.edu/encyclopedia/content.cfm?pageid=P93016

If a needle biopsy is required, here is what happens:

http://www.radiologyinfo.org/EN/INFO.CFM?PG=NLUNGBIOP&bhcp=1

Take care, and if you need more information, please feel free to add details and see what we can find for you.