Clinicopathologic features and computed tomographic findings of 52 surgically resected adenosquamous carcinomas of the lung

Background Adenosquamous carcinoma (ASC) is a rare malignant tumor with a squamous cell carcinoma (SCC) and an adenocarcinoma (AC) component. It behaves more aggressively than other histologic subtypes of lung cancer. We studied the clinicopathologic features and computed tomographic (CT) findings of ASC and assessed the effect of tumor location and the extent of the AC component in ASC on the clinical and radiologic characteristics of ASC. Methods A diagnosis of ASC was made in 53 (1.1%) of 4,923 patients who underwent resection for primary lung cancer. Fifty-two of these patients underwent preoperative high-resolution CT imaging and were enrolled in our study. Results ASC was peripherally located in 43 patients and centrally located in 9. Tumor size larger than 5 cm (p = 0.012) and CT findings of inflammatory changes surrounding the tumor (p = 0.040) were independent prognostic factors. Larger tumor size (p < 0.001), chief complaints (p = 0.01), advanced tumor stage (p = 0.03), obstructive pneumonia (p < 0.01), and CT findings of inflammatory changes surrounding the tumor (p = 0.005) were associated with central location. Twenty-four cases were predominantly AC, and 28 were predominantly SCC. Peripheral ground-glass opacity (GGO) on CT was more often seen in the AC-predominant groups (p = 0.03). Conclusions ASC patients presented with centrally located obstructive pneumonia typical of SCC and with peripheral GGO typical of lepidic AC. Tumor size that exceeded 5 cm and CT findings of inflammatory changes surrounding the tumor were strong predictors of poor prognosis.