Lung cancer in patients with idiopathic pulmonary fibrosis: CT findings

Purpose: The frequency of lung cancer in patients with idiopathic pulmonary fibrosis (IPF) is higher than that of general population. To evaluate CT findings of lung cancer associated with IPF, we analyzed 32 patients with lung cancer associated with IPF. Method: We analyzed retrospectively 32 patients with histologically confirmed lung cancer out of 244 consecutive cases diagnosed as IPF by either CT and clinical findings (n = 220) or histologically (n = 24). The patients were 40-85 years old (mean 66 years, M/F = 31/1). Scanning techniques were conventional CT in 24 patients, high resolution CT (HRCT) in 2 patients, and both conventional CT and HRCT in 6 patients. We analyzed the CT patterns, locations, and histologic types of lung cancer. Results: The frequency of lung cancer in patients with IPF was 13.1% (32/244). In 17 of 32 patients, the CT findings of lung cancer were ill defined lesions mimicking air-space consolidation. Lung cancer was located mainly in the lower lobes (21/32) and peripheral portion (21/32). Histologically, squamous cell carcinoma was the most common type (18/32). Conclusion: Typical CT findings of lung cancer were ill defined consolidation-like masses at the peripheral portion where the most advanced fibrosis was located.