Match each clinical presentation of a patient with a suspected hereditary gastrointestinal syndrome to the most accurate diagnosis.
- A 22-year-old patient presents with multiple hamartomatous polyps in the jejunum, dark macules on the buccal mucosa, and a family history of pancreatic cancer.Peutz-Jeghers syndrome
- A 34-year-old patient undergoes colonoscopy revealing over 100 adenomatous polyps. Physical examination is notable for an osteoma of the mandible and epidermoid cysts.Gardner syndrome
- A 45-year-old patient is diagnosed with proximal colon cancer. Tumor analysis shows high microsatellite instability and loss of MSH2 protein expression.Lynch syndrome
- A 19-year-old patient is found to have dozens of colonic adenomas shortly after undergoing surgical resection for a primary medulloblastoma.Turcot syndrome
- A 40-year-old patient presents with 30-40 colonic adenomas. Genetic testing reveals a biallelic autosomal recessive mutation affecting DNA base excision repair, with a normal APC gene.MUTYH-associated polyposis
Answer
The presentations map respectively to Peutz-Jeghers syndrome (hamartomas and pigmentation), Gardner syndrome (adenomas and osteoma), Lynch syndrome (mismatch repair defect and proximal cancer), Turcot syndrome (adenomas and medulloblastoma), and MUTYH-associated polyposis (base excision repair defect).
Each genetic syndrome possesses highly specific phenotypic and genotypic markers required for accurate diagnosis: Peutz-Jeghers features hamartomas and pigmentation; Gardner features osteomas; Lynch features mismatch repair defects without extensive polyposis; Turcot features CNS tumors; and MAP features base excision repair defects with an attenuated polyposis phenotype.
Step-by-Step Solution
Key Concept
Hereditary gastrointestinal polyposis and neoplastic syndromes are differentiated by their distinct polyp histology, specific extracolonic manifestations, and underlying genetic mechanisms.