腹股溝疝是在我們醫療工作中，是一種相當常見的的疾病。在患者的年齡超過了75歲的族群中，其終生患病率約為47％，但其病因非常罕見的是由癌症轉移所致。而大多數腹膜惡性腫瘤轉移至腹股溝疝多是來自胃腸道。在非腹膜惡性腫瘤轉移中，睾丸癌是最常見的腹膜外腹股溝轉移，但是從來沒有一例報告是從肺腺癌轉移。患者可能有惡性腫瘤轉移而引發腹股溝疝氣。這份報告提醒我們的腹股溝疝病理評價的重要性。否則，潛在的病理可能被錯過。

An inguinal hernia is a common medical condition in daily practice. Indeed, the lifetimeprevalence of inguinal hernias is 47% in patients > 75 years of age, but it is rare to have metastatic cancer of an inguinal hernia sac. Most cases of intraperitoneal malignant inguinal hernias arise from the gastrointestinal tract. Extraperitoneal inguinal metastases most commonly occur in males with testicular cancer; there have been no reported cases that have metastasized from lung adenocarcinoma. Here we report a 77-year-old male with possible cancerous peritonitis that led to the finding of metastases in a hernia sac. The patient presented with disease progression after chemo-radiation therapy with multiple metastases to the liver and bone. This report highlights the importance of a pathologic evaluation of the inguinal hernia sac in preventing misdiagnosis.