DEAR DR. ROACH: Are you aware of the possibility of pancreatitis resulting from long-term vitamin D2 supplementation? I was diagnosed with IPMN with chronic pancreatitis after being on 50,000 IU of vitamin D2 once a week for nine months. I had mild upper left quadrant pain, which I am told is quite unusual for pancreatic cysts. After doing some research, I decided to decrease and then stop the D2. As I did, cyst sizes and tumor markers both decreased. In addition, the pain resolved. I was fortunate enough to detect the connection, but have not had any interest from medical practitioners about looking into the possible link here. — J.D.

ANSWER: This is a complex issue, and it starts with your IPMN, which stands for “intraductal papillary mucinous neoplasms” of the pancreas. These are tumors of the pancreas that are at risk for becoming cancerous.

The size is the biggest predictor of malignancy, so your doctors are likely monitoring the size of your tumors. Those less than 2 cm in size are at low risk for malignancy. “Malignant” and “cancerous” are synonymous terms, but the boundary between benign tumors and malignant ones is not as sharp a line as we used to think.

These cystic tumors are filled with mucin and can block the main pancreatic duct or a side pancreatic duct, through which the pancreatic enzymes that help to digest food flow into the small intestine. Insulin is also produced by the pancreas, but it is transported to the body through the splenic vein into the liver rather than the ducts into the intestine. Blockage of the ducts causes ductal dilation behind the obstruction. For the subset in whom the pancreatic ducts get blocked, IPMN can also cause inflammation of the pancreas, called pancreatitis.

Scientists observed that vitamin D levels — D2 and D3, the usual kind we supplement — are low in people with any kind of pancreatitis, but vitamin D treatment often made the pancreatitis worse. This seeming paradox was resolved when it was further found that the inflammatory cells in the inflamed pancreas were making the active form of vitamin D (1,25-dihydroxy vitamin D), and high levels of this active D vitamin were increasing calcium levels. The increase made pancreatitis worse. The low levels of circulating vitamin D2 and D3 are part of the body’s response to the elevated 1,25-dihydroxy vitamin D. Vitamin D supplementation is thus not usually done in pancreatitis since it can make it worse.

With the lessening of inflammation because you stopped the D2, it’s possible the cysts decreased in size and the ducts were able to go back toward normal, relieving inflammation in your case of IPMN.

DEAR DR. ROACH: I have just been diagnosed with a Baker’s cyst behind my knee but received little information about it. Can you please tell me causes and cures? — D.O.

ANSWER: A Baker’s cyst is a common problem. It is a fluid collection behind the knee. In adults, these are usually due to increased joint fluid (from arthritis, a meniscal tear or trauma) communicating with the back of the knee through a one-way valve.

They are treated by addressing the underlying problem; for instance, anti-inflammatories and moderate exercise for arthritis. In addition, an injection of an anti-inflammatory into the joint space is usually successful in relieving symptoms. If a person is resistant to these treatments, an orthopedic surgeon has particular expertise in managing these.

* * *

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.