High-resolution computed tomography findings of early mucinous adenocarcinomas and their pathologic characteristics in 22 surgically resected cases.

Abstract Background The pathological criteria of early-stage mucinous adenocarcinoma of the lung have recently been defined; however, its characteristic radiologic imaging findings are still poorly understood. Thus, this study aimed to clarify the radiologic and pathological findings of early-stage mucinous adenocarcinoma. Materials and methods In this study, we clinicopathologically reviewed 22 cases of surgically resected mucinous adenocarcinoma in situ (AIS) and minimal invasive adenocarcinoma (MIA), and attempted to elucidate the characteristic radiologic features of early mucinous adenocarcinomas using high-resolution computed tomography (HRCT). Results Radiologically, the mean value of the maximum diameter of 22 tumours was 2.1 cm (range, 1.0–2.9 cm). Based on the HRCT findings, the tumours were divided into part-solid ground glass nodules ( n  = 11) and solid nodules ( n  = 11). The mean CT attenuation value was 25.7 HU (range, 17–35 HU). All tumours, except 3 tumours pathologically diagnosed as AIS, showed air-containing features. According to the preoperative CT findings, 7 (35%) cases were diagnosed as inflammatory nodules. Of these, 4 cases had lobular-bounded margins, and 3 showed vaguely outlined ground glass shadows. Conclusion The characteristic HRCT findings of mucinous AIS and MIA were solid or part-solid nodules with air-containing spaces. However, some AIS and MIA nodules showed lobular-bounded margins or marginally vaguely outlined ground glass shadows, and were difficult to differentiate from inflammatory nodules.