# Pancreatic infiltrative malignancy masquerading as autoimmune pancreatitis: Case report, review of radiological criteria, and literature

## TL;DR

A case report highlights the difficulty in distinguishing pancreatic cancer from autoimmune pancreatitis, leading to a delayed diagnosis and treatment.

## Contribution

The paper emphasizes the risk of misdiagnosis when pancreatic cancer is mistaken for an inflammatory condition due to histological and radiological similarities.

## Key findings

- A patient's pancreatic cancer was initially misdiagnosed as autoimmune pancreatitis based on imaging and early biopsies.
- Histological diagnosis was later confirmed as adenocarcinoma after multiple follow-ups and additional biopsies.
- The desmoplastic reaction and reliance on histology without considering radiological data contributed to the diagnostic delay.

## Abstract

We report a case of a 44-year-old male patient, who presented to the University Hospital of Salzburg, Austria with abdominal pain, persistent jaundice, and lack of appetite. Radiological work-up (CT, MRI, PET/CT) indicated a suspicious mass of the uncinate process of the pancreatic head with adjacent infiltration and regional lymphadenopathy. The differential diagnosis was between primary pancreatic cancer and focal autoimmune pancreatitis. Further laparoscopic biopsies from multiple areas, showed only fibrous scarring processes, with no malignancy. Treatment with steroids didn't give any benefits. After multiple follow-up CTs and MRs within 6 months—additional biopsies were done, which eventually demonstrated adenocarcinoma. Evidently the cancer diagnosis was much delayed and the patient started receiving chemotherapy, but radical surgery was not possible. Multiple articles and case reports can be found in the literature, that are reviewing the fact that pancreatic inflammatory processes are mimicking pancreatic tumor, but not many articles or case reports are available in the literature, where neoplastic processes are misinterpreted as inflammatory and incorrectly proven with histological examination. One of the main reasons for improper diagnosis is the desmoplastic reaction around the pancreatic malignancy. Another important aspect is the acceptance of histological diagnosis as conclusive, where no opposing arguments are specified, based on radiological criteria.