# Autoimmune Pancreatitis Associated With Progressive Giant Multilocular Pancreatic Pseudocyst and Steroid-Induced Diabetes

## TL;DR

A rare case of autoimmune pancreatitis is described where steroid treatment led to diabetes and unusual pancreatic cyst growth.

## Contribution

This paper reports a rare case of progressive giant multilocular pancreatic pseudocyst and steroid-induced diabetes in a patient with autoimmune pancreatitis.

## Key findings

- Glucocorticoid treatment in a type 1 AIP patient led to steroid-induced diabetes mellitus.
- Progressive enlarging multi-cystic pancreatic lesions were observed despite clinical improvement from steroid therapy.
- The case highlights the rare occurrence of fast-growing pancreatic cysts following treatment for type 1 AIP.

## Abstract

Autoimmune pancreatitis (AIP) is acknowledged as a benign ailment with swift responsivity to corticosteroid treatment (CST). Though past assumptions dismissed its connection to cyst formation, a few instances of AIP-linked pancreatic cysts (PCs) have been documented. While some cases responded positively to CST, others demonstrated resistance, necessitating intervention. Our case is a 50-year-old male with a known diagnosis of type 1 AIP. This case presents a specific adverse drug reaction of glucocorticoid that causes diabetes mellitus. Glucocorticoid was tapered due to clinical improvement and diabetes complications but also caused multiple flares. Additionally, in several months, CT showed progressive enlarging multi-cystic pancreatic head lesions, which cause constriction at the distal duodenal outlet and biliary ductal dilation. This case presents a specific adverse drug reaction of glucocorticoid that causes diabetes mellitus. Meanwhile, the fast-growing multi-cysts in the pancreatic head after treatment of type 1 AIP were very rare.