PTEN negative adenocarcinoma developed in a gastric hamartoma polyp of a Cowden syndrome patient.
Jumpei Suzuki, Bunichiro Kato, Hiro-O Matsushita et al.
✦ AI-curated · Sources linked
Case in brief
A man in his 60s with Cowden syndrome, diagnosed after Lhermitte-Duclos disease, medullary thyroid carcinoma and gastrointestinal polyposis, underwent regular endoscopic surveillance. A recent examination found an irregular, hemorrhagic polyp in the lower gastric body; biopsy raised concern for carcinoma, prompting endoscopic mucosal resection. Histology showed well-differentiated tubular adenocarcinoma arising within a hamartomatous polyp. PTEN expression was absent in the carcinoma and most hamartoma cells, with retained expression in some hamartoma cells; analysis confirmed a PTEN pGly127Arg mutation. The lesion was removed endoscopically.
What made this case unusual
The adenocarcinoma arose within a gastric hamartoma in a patient with Cowden syndrome, and PTEN loss was present in the carcinoma and most—but not all—hamartoma cells.
Diagnostic / clinical pearl
In Cowden syndrome, an irregular or hemorrhagic gastric hamartoma polyp may harbor adenocarcinoma; careful endoscopic assessment and histologic evaluation can identify it.
Why it matters
The case supports regular, careful endoscopic observation of hamartoma polyps in patients with Cowden syndrome to detect gastric carcinoma at an early stage.