Peripheral lung adenocarcinomas: 10 mm or less in diameter

Background Few reports have been published regarding peripheral lung adenocarcinomas that are 10 mm or less in diameter. This is considered to be the smallest tumor size detectable by present diagnostic modalities. Methods Clinicopathologic studies were performed in 57 patients with peripheral lung adenocarcinomas of 10 mm or less in diameter. Outcomes were compared with two other groups that consisted of 32 patients with adenocarcinomas between 11 and 15 mm in diameter and 35 patients with adenocarcinomas between 16 and 20 mm in diameter. Tumors were curatively resected between 1992 and 2002. Results The mean age was 61.7 years. The following three features were more frequent: female sex (78.9%), nonsmokers (77.2%), and cases with carcinoma detected by computed tomography despite negative chest radiography (96.5%). Negative lymphatic invasion (94.7%) was significantly higher. Three cases showed lymphatic invasion that was classified as types E or F, according to Noguchi’s classification. There were no cases of lymph node metastasis, pleural involvement, or intrapulmonary metastasis. Well-differentiated type was in 93.0%. Types A and B, which are noninvasive alveolar replacement-type adenocarcinomas, were significantly dominant (86.0%). The 5-year postoperative survival rate was 97.3%, which was significantly better than in the other two groups (75.5%, 78.1%). Conclusions Histopathologic features of most peripheral lung adenocarcinomas of 10 mm or less in diameter were types A and B. Types A and B were considered fundamentally indicated for thoracoscopic wedge resections. However, the other types required the standard operation.