A 70-year-old man with epigastric pain was referred to our hospital. Computed tomography and magnetic resonance imaging showed the diffusely enlarged pancreas compared to his normal pancreas 6 months prior to presentation. Serum levels of IgG4 and amylase were normal, while C-reactive protein was slightly elevated. Endoscopic ultrasound-guided fine-needle biopsy of the pancreas revealed acinar-ductal metaplasia with neutrophil infiltration and without infiltration of IgG4-positive plasma cells. After the clinical diagnosis of type 2 autoimmune pancreatitis (AIP), his symptoms spontaneously improved without steroid therapy. Three months later, radiological findings showed improved pancreas size and serological findings. The pathological diagnosis of type 2 AIP using endoscopic ultrasound-guided fine-needle biopsy is challenging, particularly for proving granulocyte epithelial lesions. This was a valuable type 2 AIP case in which the images before, at the time of onset, and at the time of spontaneous remission were evaluated.
Keywords: Acinar–ductal metaplasia; Endoscopic ultrasound-guided fine-needle biopsy; Granulocyte epithelial lesions; Type 2 autoimmune pancreatitis.
© 2023. Japanese Society of Gastroenterology.