Relation between thin-section computed tomography and clinical findings of mucinous adenocarcinoma

Detailed reports on mucinous adenocarcinoma (formerly "mucinous bronchioloalveolar carcinoma") have not been published. We evaluated the correlation between thin-section computed tomography findings and the clinicopathologic characteristics and prognosis of mucinous adenocarcinoma.

From April 1997 to March 2008, 45 resected lung carcinomas were diagnosed as mucinous adenocarcinoma. Five cases of multiple lung cancers or ambiguous mucinous adenocarcinoma were excluded. Tumors were classified as "solitary-type" or "pneumonic-type" tumors according to the thin-section computed tomography findings. We evaluated the clinicopathologic characteristics and the epidermal growth factor receptor and KRAS gene mutation statuses and correlated the thin-section computed tomography findings with patient prognoses.

Thirty patients had solitary-type and 10 had pneumonic-type tumors. The lesions in 23, 14, and 3 patients were classified as pathologic stage I, stage II, and stage III, respectively. Five patients had adenocarcinoma in situ, 9 had minimally invasive adenocarcinoma, and 26 had invasive mucinous adenocarcinoma. Thirteen patients showed recurrences, which were classified as intrapulmonary metastases in all patients. The 5-year overall and relapse-free survival rates were 83.3% and 88.8%, respectively, in patients with solitary-type tumors and 20.0% and 0%, respectively, in patients with pneumonic-type tumors (p < 0.001). The median follow-up time for surviving patients was 81 months. KRAS mutations were detected in 30 patients, but epidermal growth factor receptor mutations were absent in all patients.

Our results indicated that thin-section computed tomography findings for mucinous adenocarcinoma were useful in predicting prognosis before surgical resection. Further studies are required to improve the treatment strategy for mucinous adenocarcinoma.