Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jul 17.
doi: 10.2169/internalmedicine.5837-25. Online ahead of print.

Spontaneous Regression in Pancreatic Neuroendocrine Tumor

Mami Bamba  1 , Yuki Yamauchi  2 , Takeshi Matsumura  2
Affiliations
Free article

Spontaneous Regression in Pancreatic Neuroendocrine Tumor

Mami Bamba et al. Intern Med. .
Free article

Abstract

Spontaneous regression (SR) of pancreatic neuroendocrine tumors (pNETs) is extremely rare. We herein report a 64-year-old man with a nonfunctioning pNET that was incidentally detected during an evaluation for back pain. Imaging showed a 30-mm mass in the pancreatic tail, but surgery was delayed because of an old myocardial infarction. Four months later, follow-up imaging revealed tumor shrinkage of 20 mm without treatment. Laparoscopic distal pancreatectomy confirmed a grade 3 pNET. While ischemia was considered, factors such as mild immune response or metabolic stress may have contributed. This case suggests that ischemia and other factors may also play a role. Further research is needed to elucidate the mechanisms underlying SR in NETs.

Keywords: immune response; ischemia; pancreatic neuroendocrine tumor; spontaneous regression.

PubMed Disclaimer