Autoimmune pancreatitis with colonic stenosis: an unusual complication and atypical pancreatographic finding

Steroid Therapy and Steroid Response in Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP), a unique subtype of pancreatitis, is often accompanied by systemic inflammatory disorders. AIP is classified into two distinct subtypes on the basis of the histological subtype: immunoglobulin G4 (IgG4)-related lymphoplasmacytic sclerosing pancreatitis (type 1) and idiopathic duct-centric pancreatitis (type 2). Type 1 AIP is often accompanied by systemic lesions, biliary strictures, hepatic inflammatory pseudotumors, interstitial pneumonia and nephritis, dacryoadenitis, and sialadenitis. Type 2 AIP is associated with inflammatory bowel diseases in approximately 30% of cases. Standard therapy for AIP is oral corticosteroid administration. Steroid treatment is generally indicated for symptomatic cases and is exceptionally applied for cases with diagnostic difficulty (diagnostic steroid trial) after a negative workup for malignancy. More than 90% of patients respond to steroid treatment within 1 month, and most within 2 weeks. The steroid response can be confirmed on clinical images (computed tomography, ultrasonography, endoscopic ultrasonography, magnetic resonance imaging, and 18F-fluorodeoxyglucose-positron emission tomography). Hence, the steroid response is included as an optional diagnostic item of AIP. Steroid treatment results in normalization of serological markers, including IgG4. Short- and long-term corticosteroid treatment may induce adverse events, including chronic glycometabolism, obesity, an immunocompromised status against infection, cataracts, glaucoma, osteoporosis, and myopathy. AIP is common in old age and is often associated with diabetes mellitus (33-78%). Thus, there is an argument for corticosteroid therapy in diabetes patients with no symptoms. With low-dose steroid treatment or treatment withdrawal, there is a high incidence of AIP recurrence (24-52%). Therefore, there is a need for long-term steroid maintenance therapy and/or steroid-sparing agents (immunomodulators and rituximab). Corticosteroids play a critical role in the diagnosis and treatment of AIP.

Pancreatic cystic lesions with atypical steroid response should be carefully managed in cases of autoimmune pancreatitis

BACKGROUND AND AIM

Pancreatic cysts have been reported in cases with autoimmune pancreatitis (AIP) and are often treated by corticosteroid; however, their response to steroid has not been determined fully. We aimed to see the incidence and steroid response of pancreatic cysts and the features of cysts without proper response in cases with AIP.

METHODS

Fifty-eight AIP cases were analyzed for the incidence and associated factors of pancreatic cystic lesions (≥ 10 mm). Of these, 47 cases, determined for steroid response, were retrospectively investigated for the factors associated with cyst change by corticosteroid therapy.

RESULTS

At initial diagnosis, 17 pancreatic cystic lesions were recognized in 13 cases (22.4%) of AIP, with an average size of 30 mm (range: 11-130 mm), associated with higher incidence of elevated serum amylase (38.5% vs 11.1%, P = 0.02). Of these 13 cases, nine cases with 10 cystic lesions underwent steroid therapy in our hospital. All of seven unilocular cysts were dramatically shrunken or vanished in a few months; meanwhile, three cases with multilocular cysts showed scarcely any steroid response (P = 0.008). Of these three cases, two cases were revealed to accompany pancreatic ductal carcinoma, in contrast to null of seven unilocular cysts (P = 0.07).

CONCLUSIONS

Pancreatic cystic lesions are sometimes recognized in cases with AIP, and most unilocular cysts can be minimized by corticosteroids. However, clinicians must be alert for atypical pancreatic cysts, such as multilocular cysts or cysts without obvious steroid response.

Colovesical fistula caused by glucocorticoid therapy for IgG4-related intrapelvic mass

IgG4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory disorder that can occur in almost all systemic organs and generally responds to corticosteroid treatment. We report a rare case of an IgG4-related intrapelvic mass lesion that responded to steroid therapy but caused a fistula between the sigmoid colon and bladder. A 71-year-old man was followed after treatment for hepatocellular carcinoma. Follow-up computed tomography (CT) incidentally depicted left hydronephrosis with an ill-demarcated intrapelvic mass lesion. This lesion was histologically diagnosed as IgG4-RD by open biopsy, and peroral steroid therapy was initiated. One month after starting steroids, a colovesical fistula was detected by follow-up CT. A colostomy and urethral catheterization were emergently performed. The patient recovered and the mass lesion was drastically minimized by the initiation of glucocorticoids; however, he still needs urethral catheterization. IgG4-RD develops in various systemic organs and generally responds well to steroids. Clinicians must be watchful for the complications of responses to corticosteroids, such as fistulization, when the mass lesion of IgG4-RD is adjacent to multiple luminal organs.

[Multiple smooth colon stenosis in 76-year-old female patient]

Differential diagnostic aspects of colon stenoses are discussed using the example case of a female patient presenting with multilocular colon metastases, who had lobular breast cancer 9 years previously. Typical is linitis plastica, which can indicate tumorous infiltration not only of the stomach, but also of the large intestine. Other endoscopic imaging and histological studies may, however, fail. The pathologist requires the anamnestic data relating to the breast cancer for exact assignment of the tumorous infiltration.