B43-56 A Case of Follicular Bronchiolitis and Connective Tissue Disease-associated Interstitial Lung Disease

Abstract Introduction A common pulmonary diagnostic dilemma is the patient with respiratory symptoms and abnormal but non-specific findings on serology, pulmonary function testing, and imaging. We present an unusual case of combined small airway and parenchymal lung disease for which wedge resection biopsy and multidisciplinary discussion were crucial for determining the underlying diagnosis. Case Report A 56-year-old female with past medical history of obesity, obstructive sleep apnea, right upper lobe hamartoma, and remote 5 pack-year smoking history presented for evaluation of productive cough and episodic wheezing after previously being given the diagnosis of asthma. Episodes of cough and wheezing were treated with oral corticosteroids, yet the patient’s history was inconsistent with asthma. Pulmonary function testing indicated normal spirometry without bronchodilator response and reduced diffusing capacity for carbon monoxide (64% predicted). Extensive serologic work-up was notable for mildly elevated anti-RNP antibody and rheumatoid factor. Computed Tomography (CT) of the chest revealed upper lobe predominant subpleural reticular changes as well as ground glass opacities, micronodules, and mild paraseptal emphysema which had been present for at least 2.5 years. Despite interdisciplinary discussion, the etiology of her symptoms and interstitial lung disease remained uncertain. Given her overall clinical stability, serial monitoring was advised. Approximately two years after presentation, the patient had persistent symptoms associated with progression of fibrosis on CT, so the decision was made to proceed with wedge biopsy via video-assisted thoracic surgery. Pathology revealed numerous reactive lymphoid follicles with some germinal centers predominately associated with the airways as well as microscopic honeycombing and focal areas of acute and organizing pneumonia. Additionally, repeat CT scan six months after biopsy revealed progression of parenchymal involvement in a nonspecific interstitial pneumonia (NSIP) pattern. Multidisciplinary interstitial lung disease (ILD) conference concluded that the diagnosis was most consistent with follicular bronchiolitis with concurrent connective tissue disease-associated ILD (CTD-ILD) without a specific underlying autoimmune disorder. Immunosuppression with azathioprine was initiated with repeat clinical assessment pending. Discussion Follicular bronchiolitis should be considered in patients with chronic respiratory symptoms, especially those with symptoms refractory to asthma-targeted therapy or signs of small airway disease on CT. If small airway involvement is strongly suspected and asthma has been excluded, surgical or cryobiopsy is often necessary for pathologic diagnosis. Pathologic findings consistent with follicular bronchiolitis should prompt investigation for underlying systemic disorders as idiopathic follicular bronchiolitis is rare. Autoimmune disorders, especially Sjogren’s syndrome and rheumatoid arthritis, can be associated with both bronchiolitis and NSIP. This abstract is funded by: None