There are two terms in pulmonology I keep mixing up: fibrosis and sarcoidosis. I finally sat down to sort things out in my head and write a post, which I hope will benefit my readers, too. 😊

Fibrosis is the overgrowth of connective tissue and scarring, usually as a result of chronic inflammation following infection, trauma, radiation, and so on. Fibrosis can develop in many organs, including the lungs. And fibrotic changes in the lungs (pulmonary fibrosis) can accompany a variety of underlying conditions.

Sarcoidosis is a systemic disease characterized by formation of epithelioid-cell granulomas in different organs. Granulomas are collections of immune and epithelioid cells that either resolve over time or are replaced by connective tissue. The exact cause of sarcoidosis is still unknown: it may be bacteria or other pathogens, or a combination of different factors.

And there is a combo: fibrotic sarcoidosis. This term means that a patient with sarcoidosis has (1) lung involvement and (2) overgrowth of connective tissue in the lungs. You can see what fibrotic sarcoidosis looks like on one of my favorite resources, Radiopaedia.

Do you have your own “favorite” pairs of terms — the ones that never quite stay put in your head? Share them in the comments.