A 40 year old man presents with insidious gradual shortness of breath. He gets dyspneic on exertion and has a cough, fatigue, weight loss, and low-grade fever. His physical exam is pretty much normal. His labs show polycythemia, hypergammaglobulinemia, and increased LDH. Chest X-ray is below:
High resolution CT scan shows homogeneous ground glass opacities. Pulmonary function tests show a restrictive ventilatory defect. A bronchioalveolar lavage results in an opaque milky fluid which settles upon standing.
Challenge: Aha! Your diagnosis is...?
Image shown under Fair Use.