American Board of Internal Medicine (ABIM) Certification Practice Exam

What condition is indicated by the presence of metachronous or synchronous cancers in specific organs for Lynch syndrome?

1. Biliary tract cancers

2. Carcinoid tumors

3. Colorectal cancer

4. Endometrial cancer

The correct answer is: Colorectal cancer

Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer (HNPCC), is characterized by an increased risk of certain types of cancers due to mutations in DNA mismatch repair (MMR) genes. One of the hallmark features of Lynch syndrome is the occurrence of metachronous (cancer occurring at different times) or synchronous (cancer occurring simultaneously) tumors in specific organs. Colorectal cancer is a key component of Lynch syndrome, and individuals with this condition have a significantly higher lifetime risk of developing it compared to the general population. The development of multiple primary cancers, particularly in the colorectum, is a critical clinical feature that informs the diagnosis and management of Lynch syndrome. While endometrial cancer is also associated with Lynch syndrome, the question specifically refers to the condition that primarily indicates the presence of cancers in the context provided. Since colorectal cancer was the first cancer identified in association with Lynch syndrome and is often considered the prototypical cancer of the syndrome, it aligns perfectly with the question context. The other options, such as biliary tract cancers and carcinoid tumors, are not primary indicators of Lynch syndrome and do not specifically relate to its classical presentation or genetic underpinnings.