Shinshu M ed J, 63⑹ :417〜418, 2015

Letter to the Editor
Treatment of a Huge Pancreatic Pseudocyst Associated withAutoimmune Pancreatitis
Norikazu ARAKURA , Tetsuya ITO , Eiji TANAKAand Takeji UMEMURA
1) Endoscopic Examination Center, Shinshu University Hospital2) Department of Medicine, Shinshu University School of Medicine

Dear Sir,
Pancreatic pseudocysts are lesions associated typically with acute and chronic pancreatitis.Since spontaneous resolution of massive pseudocysts is very unlikely, drainage by endoscopic or surgical means is arecommended ﬁrst line of treatment.However,this may not be the case for cysts associated with autoimmune
pancreatitis (AIP).
A 70‑year‑old man had noticed a slowly growing epigastric mass 9 months prior to hospital admission for
epigastric pain and diﬃculty eating. Slight jaundice and a large epigastric mass with mild tenderness weredetected by physical examination.Laboratory data showed abnormalities in blood cell counts and biochemical
tests,including white blood cells 12,850/μl,total bilirubin 2.6 mg/dl,alanine aminotransferase 40 U/l,aspartate
aminotransferase 49 U/l,alkaline phosphatase 1,006 U/l (normal:115‑330 U/l),γ‑GTP 90 U/l (normal:13‑70U/l), pancreatic amylase 243 U/l (normal:22‑55), and lipase 138 U/l (normal:11‑53 U/l). Imaging examinations (Fig. A, B)revealed a huge cystic lesion of over 100 mm in diameter with uniform ﬂuid content in theleft upper abdomen. Diﬀuse narrowing of the pancreatic duct in the head and body of the pancreas which
separated from the cystic lesion,and narrowing of the intrapancreatic bile duct with corresponding dilatationof upstream bile ducts due to segmental enlargement of the pancreatic head were observed.We also noted soft
tissue which surrounded the abdominal aorta.Based on these radiological abnormalities and high serum IgG4352 mg/dl (normal:4‑108),the patient was diagnosed as having pancreatic pseudocyst due to AIP.Sclerosing
dacryoadenitis, sialoadenitis and chest abnormalities including hilar lymphadenopathy were not observed.
It has been reported that narrowing of the pancreatic duct and subsequent retention of pancreatic juice
associated with AIP improves rapidlywith prednisolone(PSL)therapy.

Accordingly,the patient commenced

PSL treatment at 0.5 mg/kg daily, and the large cyst found on admission was dramatically decreased in size
after only 1 week of therapy (Fig. C, D). The narrowing and associated dilatations of bile ducts were also
improved.
We previously described the clinical outcomes of 3 patients with pancreatic pseudocyst associated withAIP .Although the cysts responded well to PSL,their sizes (largest :60×36 mm)were much smaller than thatin the present case. Kubota et al . observed that while small cysts tended to respond favorably to PSLtreatment,large cysts of over 55 mm in diameter did not.However,the present pseudocyst which was larger
than 100 mm in diameter exhibited a rapid and drastic improvement with steroid therapy,suggesting that PSL
can be considered a ﬁrst‑line drug for all sizes ofCorresponding author:Takeji Umemura
Department of M edicine, Shinshu University School ofMedicine, 3‑1‑1 Asahi, M atsumoto, Nagano 390‑8621,
Japan

AIP ‑associated pancreatic pseudocysts. Theseﬁndings may spare patients and medical staﬀfrom
possibly unnecessary pseudocyst drainage.

E‑mail:tumemura＠shinshu‑u.ac.jp

No. 6, 2015417

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Imaging examinations.Fig.A (CT),B‑1 (MR)and B‑2 (schema of M RI)are images taken
upon patient admission.Fig.C (CT),D‑1 (M R)and D‑2 (schema of M RI)were obtained at 1week after commencement ofprednisolone therapy.The arrow indicates the narrowing ofthe
intrapancreatic bile duct. Small arrowheads denote the pancreatic duct. Large arrowheads
demarcate the inner margins of the cystic lesion.

References1) M uraki T, Hamano H, Ochi Y, Arakura N, Takayama M , Komatsu K, Komiyama Y, Kawa S, Uehara T,Kiyosawa K :Corticosteroid‑responsive pancreatic cyst found in autoimmune pancreatitis. J Gastroenterol. 40:761‑766, 2005
2) Kubota K,Fujita Y,Sato T,Sekino Y,Hosono K,Kobayashi N,Fujisawa N,Kagawa K,Fujisawa T,Matsuhashi
N,Tanida E,Sakaguchi T,Endo I,Nakajima A :Autoimmune pancreatitis associated with pancreatic cyst :how
can we manage it ?J Hepatobiliary Pancreat Sci 21:902‑910, 2014（2015. 6.18 received ; 2015. 7. 7 accepted）

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