Histopathology of Connective Tissue Disease-Associated Pleuropulmonary Disease

Pulmonary complications associated with autoimmune connective tissue disease (CTD) are common causes of clinical interstitial lung disease (ILD). Pleural manifestations are dominated by inflammation and varying amounts of diffuse fibrosis. In the lung, a wide spectrum of histologic injury patterns are encountered in every anatomic location including small airway disease most commonly in the form of chronic bronchiolitis, vascular changes, and interstitial lung disease ranging from diffuse alveolar damage to advanced pulmonary fibrosis. The most common interstitial pattern, seen in nearly all of the different CTDs, is a cellular and variably fibrotic ILD referred to as nonspecific interstitial pneumonia (NSIP). Each of the major CTDs has particular manifestations more commonly manifested, but the histopathologic changes found in these CTDs are often not specific and a definitive diagnosis usually requires detailed clinical, serologic, and pathologic correlation as well as close patient follow-up.