Answer: Lymphangioleiomyomatosis (LAM)

Notice the scatter, varying sized, thin walled cysts within the lungs as well as the left pneumothorax. While there are several things in the differential, give the patient’s age and the pneumothorax (which was recurrent by the way), this all fits most with LAM (which patient had a known diagnosis of)

DDX:

Langerhans Cell Histiocytosis - young pt with h/o of cigarette use

LIP (lymphocytic interstitial pneumonia) - classically has small nodules and ground glass findings

Reference: https://radiopaedia.org/articles/lymphangioleiomyomatosis-1