Correct!
Answer: 2. Fiberoptic bronchoscopy
Given that pulmonary alveolar proteinosis is the leading diagnostic consideration, fiberoptic bronchoscopy is the most appropriate procedure to definitively establish a diagnosis. In selected cases, surgical lung biopsy may be required to establish the diagnosis of pulmonary alveolar proteinosis, but bronchoscopy is generally the first choice and is sufficient for most patients. Percutaneous transthoracic lung biopsy is generally not employed for the diagnosis of diffuse lung diseases, and surveillance CT is not indicated given that a working diagnosis in need of tissue confirmation is present. Pleuroscopy is not a relevant consideration in this circumstance given the working diagnosis and the lack of pleural disease.)
Clinical Course: Bronchoscopy with lavage was performed and milky periodic acid-Schiff positive, phospholipoproteinaceous fluid was found, confirming the diagnosis of pulmonary alveolar proteinosis. The patient continued to complain of headache, and brain MRI (Figure 3) was performed.
Figure 3: Axial brain MRI contrast-enhanced T1-weighted images.
What is the likely cause of the patient’s brain MRI findings?