Adenosquamous carcinoma of the lung: CT, FDG PET, and clinicopathologic findings

PURPOSE: The aim of this study is to evaluate CT, FDG PET, and clinicopathologic features of the adenosquamous carcinoma of the lung (ASC). PATIENTS AND METHODS: Twenty-six patients (M/F = 20:6; mean age, 65.0 years) who underwent surgical resection of ASC were included. The tumors were assessed in terms of size, location, morphologic characteristics, and maximum standardized uptake value (SUVmax) on CT and FDG PET. Proportion of adenocarcinoma was determined. The central and peripheral groups were compared. The differences in disease-free survival among the groups according to the observations were analyzed by Kaplan-Meier test for patients who underwent curative resection (n = 21). RESULTS: Diameter was 3.8 ± 1.9 cm. Five tumors were located centrally (19.2%) and 21 tumors peripherally (80.8%). Internal low and heterogeneous attenuation was found in all patients. Margins were lobulated in 20 (80%) patients, spiculated in 23 (92%), and ill-defined in 23 (92%). SUVmax was 8.3 ± 3.9. Adenocarcinoma proportion was 33 ± 28%. Central ASC were larger than peripheral ASC (5.7 cm vs. 3.4 cm, P = 0.007). Only SUVmax >6.3 was a poor prognostic factor. CONCLUSION: ASC was more commonly peripheral than central, and showed internal low and heterogeneous attenuation and possessed lobulated, spiculated, or ill-defined margin on CT. Mean SUVmax of ASC was 8.3 ± 3.9. Central ASC was larger than peripheral ASC. Except for tumor size, central ASC and peripheral ASC showed no significant differences in pathology, FDG PET, and survival. Higher SUVmax was a poor prognostic factor.