Correct!
3. Bronchoscopy with bronchoalveolar lavage
Bronchoscopy with bronchoalveolar lavage is the best choice for the next step in the evaluation of this patient. Serial thoracic CT is unlikely to provide management-altering information. Such an approach could be of benefit if there were clinical features of infection or increased pressure / hydrostatic pulmonary edema and presumptive treatment was implemented, but the patient’s clinical history does not suggest these possibilities. 18FFDG-PET scanning is useful for evaluation of pulmonary nodules and staging of malignancy, but is not typically employed for diffuse lung disease evaluation; neither the presence nor the absence of tracer accumulation within the pulmonary opacities would provide management-altering information. Percutaneous transthoracic fine needle aspiration biopsy is usually reserved for nodular lung lesions and is not typically employed for diffuse lung diseases. Surgical lung biopsy is often used for the evaluation of diffuse lung diseases and could provide the diagnosis in this case, but may not be needed in this circumstance because bronchoscopy may be able to obtain the diagnosis in a far less invasive fashion. It is prudent to attempt the less costly and less invasive procedure first, and reserve the more costly and potentially morbid procedure if more conservative approaches are unrevealing.)
The patient subsequently underwent bronchoscopy with bronchoalveolar lavage, and the returned lavage fluid had the appearance shown in Figure 4.
Figure 4. Photograph of bronchoalveolar lavage fluid shows a milky white appearance of the effluent.
Microscopic analysis of the lavage fluid revealed numerous, PAS-positive acellular globules (Figure 5).
Figure 5. Light microscopy of BAL fluid specimen shows extensive accumulation of extracellular granular eosinophilic proteinaceous material.
What is the likely diagnosis?