Clinicopathological features of colloid adenocarcinoma of the lung: A report of six cases

Objectives: Colloid adenocarcinoma of the lung (CA) is a rare neoplasm that is associated with abundant mucin, which destroys alveoli. We evaluated the clinicopathological features of CA. Methods: A total of 4,648 patients underwent surgical resection of primary lung cancer at our institution from 2002 to 2014. We analyzed the clinicopathological features of CA in six (0.13%) of these patients. Results: All patients were asymptomatic. The median age was 60.5 years. The median tumor size was 2.4 cm. All tumors appeared as solitary solid nodules on computed tomography (CT). Four of the six showed intense ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG–PET) accumulation, and the remaining two showed weak ¹⁸F-FDG accumulation. All patients underwent lobectomy with systematic lymph node dissection. Histologically, CAs presented with various degrees of a non-mucinous component in addition to abundant mucin. Only one patient with pN2 had recurrence. Conclusions: On CT, CA appears a solitary solid nodule. Further, FDG–PET findings present various ¹⁸F-FDG accumulations. Lobectomy with systematic lymph node dissection is an appropriate procedure in view of lymph node metastasis. Since the definitive diagnosis of CA of the lung is difficult, further immunohistochemical and genetic analyses are needed. J. Surg. Oncol. 2016;114:211–215.