A case of mucinous (“colloid”) adenocarcinoma that was difficult to diagnose by intraoperative histopathological frozen sectioning

Abstract

A 70-year-old man was noted to have an abnormal shadow in the left lung during screening with chest radiography. A chest CT revealed an 8-mm nodule in S¹⁰ of the left lung. He was followed for one year, and was then admitted to our hospital for examination and treatment of the pulmonary nodule as it had not changed. We performed a partial resection of the left lung using a thoracoscopic surgical procedure. The intraoperative histopathological diagnosis did not show a malignant tumor. However, the final pathological diagnosis was mucinous (“colloid”) adenocarcinoma. We performed another operation (left lower lobectomy and lymph node dissection ND2a-2) using a totally thoracoscopic surgical procedure after obtaining informed consent. The pathological stage was pT1aN0M0-IA. Mucinous (“colloid”) adenocarcinoma is a rare histological type of lung cancer. The difficulty of diagnosing mucinous (“colloid”) adenocarcinoma should be taken into consideration.