Fig. 25.1 Cystic fibrosis in a 23-year-old man. (a–c) Lung window images of CT scans (2.5-mm section thickness) obtained at levels of great vessels (a), lower lobar bronchi (b), and inferior pulmonary veins (c), respectively, show areas of bronchiectasis (arrows), tree-in-bud signs (arrowheads), and mucus plugging (open arrows). Also note

mosaic perfusion areas (curved arrows). (d) Low-magnification (×4) photomicrograph of surgical biopsy specimen discloses bronchiolar dilatation (arrows) owing to luminal impaction of mucus and inflammatory exudates. Also note bronchiolar wall thickening (arrowheads) with chronic inflammation and fibrosis

Cystic Fibrosis

Pathology and Pathogenesis

Cystic fibrosis is an autosomal recessive disease with the mutation of cystic fibrosis transmembrane conductance regulator gene and multisystem involvement. Patients have abnormal transport of chloride and sodium across the respiratory epithelium, resulting in thickened airway secretions and susceptibility to recurrent infections. Gross pathologic findings for end-stage disease show widespread bronchiectasis (more severe in upper lobe) with thick mucus plugs, pleural fibrosis or adhesions, pneumonic consolidation, and lobar atelectasis. Microscopically, there are acute and chronic inflammation involving the large and

small airways associated with bronchial gland and goblet cell hyperplasia, squamous metaplasia, and mucostasis [1] (Fig. 25.1).

Symptoms and Signs

Since cystic fibrosis is a genetic disease resulting in complications in multiple organs, especially involving the lungs and pancreas, it mimics a number of other diseases. Usual respiratory presentations in adults include cough, sputum, wheezing dyspnea, recurrent respiratory tract infection, and cor pulmonale if advanced. Usual gastrointestinal presentations in adults are recurrent abdominal pain, biliary cirrhosis with portal hypertension, and recurrent pancreatitis. Infertility may occur.