Cystic lung lesions in Sjogren syndrome: analysis of lymphocyte subsets in tissue with clinico-radiologic-pathologic correlation

Pulmonary complications associated with Sjögren syndrome (SS) have attracted attention in recent years. Sjögren syndrome has been associated with small cyst formation in salivary glands, thymus, and lungs and has been recently brought to the forefront by radiologists due to high-resolution techniques. However, pathologists are less aware of this finding unless clinico-radiologic-pathologic correlation is sought. Formation of large bullae in SS is a rare complication with potential for confusion with other diseases. Here, we present the clinical, radiologic, and pathologic findings in 3 patients with SS associated with multiple pulmonary cystic lesions. All 3 patients had a variable mixed restrictive and obstructive component of the disease. There was good correlation with the pulmonary function tests (PFTs), high-resolution computed tomographic scan, and morphology with regard to the restrictive component. The small cysts appear to correlate with the extent of obstructive changes on the PFTs. However, the large bullae do not, implying noncommunication with the conducting airways. This noncorrelation between the PFTs and extent of bullous disease with predominant involvement of lower lobes in SS enables distinction from bullous emphysema. The mechanism of bulla formation in SS appears to be different from bullous emphysema. A check valve mechanism has been proposed previously in SS, which does not explain cyst formation in the thymus. Alternately, inflammation may play a role with the key suspects being CD4 T-helper cells and perhaps NK cells. This is the first report of a clinico-radiologic-pathologic correlation with analysis of lymphocyte subsets.