Autoimmune pancreatitis mimicking pancreatic tumor.
There are two forms of autoimmune pancreatitis (AIP), type 1 is called 'lymphoplasmocytic sclerosing pancreatitis' and type 2 is the 'idiopathic duct-centric pancreatitis'. AIP type 1 seems to be a member of the 'IgG4-related group of diseases', associated with high serum level of IgG4 gamma globulin fraction, IgG4-positive plasma cell tissue infiltration and sclerosis [1-4].
A 60-year-old male is presented with abdominal pain. On CT scan, a 70 x 66 x 48 mm' lesion was identified in the tail of the pancreas. Repeated aspiration demonstrated no malignancy, tumor markers were within the normal range. Control imaging studies showed enlargement of the mass, infiltrative growth, venous compression and appearance of a pathologic lymph node, suggesting a malignant process, therefore we decided surgical exploration (Fig. 1). A solid, malignantly appearing lesion was identified in the body and tail of the pancreas, infiltrating the splenic hilum and transverse colon. A pylorus-preserving total pancreatectomy with splenectomy and extended right hemicolectomy was performed with an uneventful postoperative recovery (Fig. 2).
On histological examination, both lesions contained elongated spindle cells, infiltration of plasma cells, lymphocytes, histiocytes and eosinophilic granulocytes. There was no evidence of malignancy. Large number of plasma cells were IgG positive, and 40% of the cells were IgG4 positive (Fig. 3).
Laboratory tests proved an elevated IgG4 level (2.4 g/l).
About 20% of AIP is still diagnosed after surgical resection. The question arises whether it is possible to reduce the number of unnecessary operations, since AIP can be treated with steroids [5-7].
Diagnostic work up based on the International Consensus Diagnostic Criteria .
Endoscopic retrograde cholangiopancreatography (ERCP) images can be so characteristic, which combined with any other positive test result can confirm the diagnosis of AIP. Our patient had no jaundice, so the indication for preoperative ERCP was not self-evident--perhaps this test could have brought us closer to the diagnosis.
CT, MRI or Magnetic Resonance Cholangiopanreatography (MRCP) can also show typical signs (sausage-like broadening, infiltration of adipose tissue, ring-like delayed contrast enhancement and altering density distribution), but alone none of the tests is sufficient to verify the diagnosis.
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Transabdominal or endoscopic ultrasound-guided pancreatic Fine Needle Aspiration Biopsy (FNAB) is a valuable method detecting pancreatic cancer. However, a negative cytological finding does not exclude pancreatic cancer. Whenever AIP is suspected, EUS--FNAB or core biopsy is recommended, and alone the positivity of this test is sufficient for making the diagnosis. Demonstrating v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations from the FNAB sample further helps to distinguish AIP for malignant pancreatic disease, since KRAS mutation is found in 90% of patients with pancreatic cancer, but never in AIP [8, 9].
The serum IgG4 level can be elevated up to 70-90% in AIP type 1; however, 10% of pancreatic cancers can present with an increased IgG4. A 2-fold increase of IgG4 concentration could be the watershed value.
Elevated CA 19-9 level is typical for ductal pancreas adenocarcinoma; however, a slight increase of CA 19-9 levels can be observed in 20% of AIP patients as well, but rarely elevated above 200 U/ml [7, 10].
AIP responds well to steroid therapy. If this disease is suspected, a so-called 'steroid trial' might be used. However, patients with pancreatic cancer can also experience a lessening of their complaints; therefore, this 'trial' could be used only by patients with tumor-negative core biopsies, in specialized centers when other AIP-specific criteria are present .
Focal lesions of the pancreas should always be considered as malignant, unless other disease cannot be unequivocally verified. On the other hand, retrospectively analyzing this case, we came to the conclusion that even in the case of a pancreatic lesion described by the imaging studies as clearly malignant, a possibility of a rare disease such as AIP should be taken into consideration. This could change the treatment dramatically.
KD proposed the study. KD and DT performed research and wrote the first draft. FS, AT collected the data. All authors contributed to the design and interpretation of the study and to further drafts. AB is the guarantor. Ethical approval is not required for this study.
Conflict of interest
No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
Received 22 August 2012; revised 11 September 2012; accepted 13 September 2012
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[2.] Stone JH, Zen Y, Deshpande V. IgG4-related disease. N Engl J Med 2012;366:539-51.
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[4.] Okazaki K, Uchida K, Koyabu M, Miyoshi H, Takaoka M. Recent advances in the concept and diagnosis of autoimmune pancreatitis and IgG4-related disease. J Gastroenterol 2011;46:277-88.
[5.] Psarras K, Baltatzis ME, Pavlidis ET, Lalountas MA, Pavlidis TE, Sakantamis AK. Autoimmune pancreatitis versus pancreatic cancer: a comprehensive review with emphasis on differential diagnosis. Hepatobiliary Pancreat Dis Int 2011;10:465-73.
[6.] Takuma K, Kamisawa T, Gopalakrishna R, Hara S, Tabata T, Inaba Y, et al. Strategy to differentiate autoimmune pancreatitis from pancreas cancer. World J Gastroenterol 2012;18:1015-20.
[7.] Wakabayashi T, Kawaura Y, Satomura Y, Watanabe H, Motoo Y, Okai T, et al. Clinical and imaging features of autoimmune pancreatitis with focal pancreatic swelling or mass formation: comparison with so-called tumor-forming pancreatitis and pancreatic carcinoma. Am J Gastroenterol 2003;98:2679-87.
[8.] Eloubeidi MA, Jhala D, Chhieng DC, Chen VK, Eltoum I, Vickers S, et al. Yield of endoscopic ultrasound-guided fine-needle aspiration biopsy in patients with suspected pancreatic carcinoma. Cancer 2003;99:285-92.
[9.] Khalid A, Dewitt J, Ohori NP, Chen JH, Fasanella KE, Sanders M, et al. EUS--FNA mutational analysis in differentiating autoimmune pancreatitis and pancreatic cancer. Pancreatology 2011;11:482-6.
[10.] Ghazale A, Chari ST, Smyrk TC, Levy MJ, Topazian MD, Takahashi N, et al. Value of serum IgG4 in the diagnosis of autoimmune pancreatitis and in distinguishing it from pancreatic cancer. Am J Gastroenterol 2007;102:1646-53.
Kristof Dede (1) *, Ferenc Salamon (2), Andres Taller (3), Daniel Teknos (1) and Attila Bursics (1)
(1) Department of Surgery-Vascular Surgery, Uzsoki Street Hospital, Budapest, Hungary, (2) Department of Pathology, Uzsoki Street Hospital, Budapest, Hungary and (3) Department of Gastroenterology, Uzsoki Street Hospital, Budapest, Hungary
* Correspondence address. Department of Surgery, Uzsoki Street Hospital, 1145 Budapest, Uzsoki u.29, Budapest, Hungary. E-mail: email@example.com
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|Title Annotation:||Case Report|
|Author:||Dede, Kristof; Salamon, Ferenc; Taller, Andres; Teknos, Daniel; Bursics, Attila|
|Publication:||Journal of Surgical Case Reports|
|Article Type:||Case study|
|Date:||Nov 1, 2012|
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