Review Question - QID 100855

This patient's presentation is consistent with idiopathic pulmonary fibrosis (IPF). On biopsy, one would expect to see patchy interstitial fibrosis, fibroblastic proliferation ("fibroblastic foci"), and cystic spaces lined by hyperplastic type II pneumocytes or bronchiolar epithelium ("honeycomb fibrosis").

This pattern seen on biopsy is known as "usual interstitial pneumonia" (UIP) and is also seen in diseases of known etiology including pneumoconioses, hypersensitivity pneumonitis, and collagen vascular diseases. IPF is commonly seen in patients aged 50-70 years old with a slight male predominance and more common in smokers. Progression begins with insidious onset dyspnea and cough, with stepwise deterioration and acute exacerbations. Clubbing is seen in 25-50% of patients. Diagnosis is commonly made by CT features or lung biopsy if diagnosis is uncertain. No pharmacologic treatment has been demonstrated to improve mortality.

Illustration A shows histologic findings of subpleural cystic enlargement seen in IPF. Illustration B shows a CT scan from a patient with IPF - honeycombing present. Illustration C shows a physical exam finding of digital clubbing which occurs in pulmonary conditions such as COPD or IPF.

Incorrect Answers:
Answer 2:Charcot-Leyden crystals are seen in asthma.
Answer 3: Hyaline membranes are seen in ARDS.
Answer 4: Arteriovenous malformations of the lung may be seen in Osler-Weber-Rendu syndrome (Hereditary Hemorrhagic Telangiectasia).
Answer 5: Anti-GBM antibodies are characteristic of Goodpasture's syndrome.