A 28-year-old woman presented to the hospital with a 6-month history of dry cough. She was a lifetime nonsmoker and reported having no fevers, joint aches, eye pain, or rashes. On physical examination, auscultation of both lower lungs revealed fine crackles. High-resolution computed tomography (CT) of the chest showed mediastinal lymphadenopathy and diffuse ground-glass opacities (Panel A, axial view). Also visible were areas of superimposed interlobular and intralobular septal thickening, a pattern known as crazy paving because of the resemblance to irregular paving stones (Panel A, box). The serum level of angiotensin-converting enzyme was 80 U per liter (reference range, 17 to 55). A subsequent transbronchial lung biopsy showed multiple noncaseating granulomas (Panel B, inset showing granuloma; hematoxylin and eosin stain). Bronchoalveolar-lavage cultures, histopathological analysis, and molecular testing were negative for infectious organisms, including Mycobacterium tuberculosis. A diagnosis of pulmonary sarcoidosis was made. The crazy-paving pattern is commonly associated with pulmonary alveolar proteinosis, but it is also seen in a variety of other conditions, such as acute respiratory distress syndrome, Pneumocystis jirovecii pneumonia, and sarcoidosis, as in this case. A tapering dose of prednisone was initiated. By 6 months after the initiation of treatment, the patient’s symptoms had abated and the radiographic findings had greatly improved (Panel C). At that point, prednisone was discontinued, and the patient’s condition stabilized. The associated symptoms did not recur, and repeat chest CT after 1 year of follow-up did not suggest progression of the lesions.

Source: NEJM