Lung cancer rarely occurs in young patients. Recent studies have demonstrated that epidemiologic data are closely correlated to some molecular characteristics. We investigated the clinicopathologic characteristics of lung adenocarcinoma in young patients and evaluated immunohistochemically detected epidermal growth factor receptor (EGFR) mutation status and anaplastic lymphoma kinase (ALK) positivity. Among lung adenocarcinoma patients, 31 cases were of the ≤ 40 yr-old group and 261 cases of > 50 yr-old group. Young patients were more likely to be females (67.7% vs 40.2%), and nonsmokers (58.1% vs 45.2%) and more often had high TNM stage (stage IV was 80.6% vs 52.1%) and had a high rate of distant metastasis (51.6% vs 28.0%) compared with older patients. The signet ring cell feature was more common (25.8% vs 11.5%) and lepidic growth pattern was rarely present (3.2% vs 16.5%) in the adenocarcinoma of young patients. There was no significant survival difference between the two age groups. The rate of EGFR mutation status and ALK positivity did not show a statistical difference between two groups. In conclusion, lung adenocarcinoma of young patients demonstrates distinct pathologic features with frequent presence of a signet ring cell feature and rare occurrence of lepidic growth pattern. Further investigation for other genetic abnormalities would be needed.

A 74-year-old man suffered from jejunal perforation and adhesion to sigmoid colon due to adenocarcinoma associated with intraductal papillary mucinous neoplasm (IPMN) arising in a jejunal heterotopic pancreas. The jejunal lesion showed direct extension to the sigmoid colon, which was mistaken as sigmoid colon cancer by surgeons. Malignant transformation is a rare complication of a heterotopic pancreas. About half of malignancies in reported cases were ductal adenocarcinoma arising in the stomach, and the jejunal location is extremely rare. Furthermore, IPMN is also uncommon finding in a heterotopic pancreas.