What disease causes progressive fibrosis on CXR, pleural honeycombing on CT, and a restrictive pattern on PFTs?

The correct answer is Idiopathic Fibrosing Interstitial Pneumonia, which is characterized by distinct radiological and pulmonary function test findings. Progressive fibrosis noted on chest X-ray (CXR) reflects the gradual accumulation of fibrotic tissue in the lung interstitium, leading to reduced lung volume and impaired gas exchange.

On CT imaging, the presence of pleural honeycombing is a key indicator of advanced interstitial lung disease and is specifically associated with idiopathic pulmonary fibrosis. Honeycombing indicates the presence of cystic airspaces surrounded by thickened fibrotic walls, which are hallmarks of chronic lung injury and fibrosis.

The restrictive pattern observed on pulmonary function tests (PFTs) aligns with the disease's pathophysiology. In idiopathic fibrosing interstitial pneumonia, the lungs become less compliant due to fibrous tissue buildup, leading to a decreased total lung capacity and vital capacity. This differs markedly from inflammatory or obstructive diseases where lung volume may be preserved or increased.

Overall, the combination of these findings—progressive fibrosis on CXR, pleural honeycombing on CT, and a restrictive pulmonary function pattern—strongly supports a diagnosis of Idiopathic Fibrosing Interstitial Pneumonia.