Diffuse Cystic Lung Disease as the Presenting Manifestation of Sjögren Syndrome.

Interstitial lung diseases, especially lymphoproliferative disorders such as follicular bronchiolitis and lymphoid interstitial pneumonia, are commonly seen in association with Sjögren syndrome. Although the predominant computed tomographic (CT) findings in patients with lymphoid interstitial pneumonia/follicular bronchiolitis include poorly defined centrilobular nodules and ground-glass attenuation, cystic changes can be seen in approximately two-thirds of these patients. The objective of this study was to define the clinical, radiological, and histopathological features of cyst-predominant lymphoid interstitial pneumonia/follicular bronchiolitis in patients with Sjögren syndrome. We present four patients who were referred to our institution with diffuse cystic changes on chest CT imaging. All four had a presumptive diagnosis of lymphangioleiomyomatosis but were subsequently found to have Sjögren syndrome. The diagnosis was established based on the clinical symptoms of xerostomia and xerophthalmia along with serologic detection of antinuclear antibodies, rheumatoid factor, anti-Sjögren's syndrome-related antigen A (SSA)/Ro antibodies, and anti-Sjögren's syndrome-related antigen B (SSB)/La antibodies. The cystic pattern associated with Sjögren syndrome had a characteristic appearance on chest CT images. Typical features included a wide variation in cyst size, internal structure within cysts, geographic simplification of parenchymal architecture producing a "dissolving lung appearance," perivascular and often basilar-predominant distribution, and frequent association with ground-glass opacities and nodules. In a compatible clinical context, we submit that these findings can be sufficiently distinctive to obviate the need for lung biopsy, even in the absence of confirmatory serological studies or lip biopsy. Clinicians should consider occult Sjögren syndrome in the differential diagnosis of patients presenting with idiopathic diffuse cystic lung disease.