A simpler diagnostic algorithm of the Japan Esophageal Society classification for Barrett's esophagus-related superficial neoplasia.

BACKGROUND: We previously developed a Japan Esophageal Society Barrett's Esophagus (JES-BE) magnifying endoscopic classification for superficial BE-related neoplasms (BERN) and validated it in a nationwide multicenter study that followed a diagnostic flow chart based on mucosal and vascular patterns (MP, VP) with nine diagnostic criteria. Our present post hoc analysis aims to further simplify the diagnostic criteria for superficial BERN. METHODS: We used data from our previous study, including 10 reviewers' assessments for 156 images of high-magnifying narrow-band imaging (HM-NBI) (67 dysplastic and 89 non-dysplastic histology). We statistically analyzed the diagnostic performance of each diagnostic criterion of MP (form, size, arrangement, density, and white zone), VP (form, caliber change, location, and greenish thick vessels [GTV]), and all their combinations to achieve a simpler diagnostic algorithm to detect superficial BERN. RESULTS: Diagnostic accuracy values based on the MP of each single criterion or combined criteria showed a marked trend of being higher than those based on VP. In reviewers' assessments of visible MPs, the combination of irregularity for form, size, or white zone had the highest diagnostic performance, with a sensitivity of 87% and a specificity of 91% for dysplastic histology; in the assessments of invisible MPs, GTV had the highest diagnostic performance among the VP of each single criterion and all combinations of two or more criteria (sensitivity, 93%; specificity, 92%). CONCLUSION: The present post hoc analysis suggests the feasibility of further simplifying the diagnostic algorithm of the JES-BE classification. Further studies in a practical setting are required to validate these results.

Clinical Evaluation of Computer-Aided Colorectal Neoplasia Detection Using a Novel Endoscopic Artificial Intelligence: A Single-Center Randomized Controlled Trial.

INTRODUCTION: Computer-aided diagnostic systems are emerging in the field of gastrointestinal endoscopy. In this study, we assessed the clinical performance of the computer-aided detection (CADe) of colonic adenomas using a new endoscopic artificial intelligence system. METHODS: This was a single-center prospective randomized study including 415 participants allocated into the CADe group (n = 207) and control group (n = 208). All endoscopic examinations were performed by experienced endoscopists. The performance of the CADe was assessed based on the adenoma detection rate (ADR). Additionally, we compared the adenoma miss rate for the rectosigmoid colon (AMRrs) between the groups. RESULTS: The basic demographic and procedural characteristics of the CADe and control groups were as follows: mean age, 54.9 and 55.9 years; male sex, 73.9% and 69.7% of participants; and mean withdrawal time, 411.8 and 399.0 s, respectively. The ADR was 59.4% in the CADe group and 47.6% in the control group (p = 0.018). The AMRrs was 11.9% in the CADe group and 26.0% in the control group (p = 0.037). CONCLUSION: The colonoscopy with the CADe system yielded an 11.8% higher ADR than that performed by experienced endoscopists alone. Moreover, there was no need to extend the examination time or request the assistance of additional medical staff to achieve this improved effectiveness. We believe that the novel CADe system can lead to considerable advances in colorectal cancer diagnosis.

Diagnostic utility of a novel magnifying endoscopic classification system for superficial Barrett's esophagus-related neoplasms: a nationwide multicenter study.

BACKGROUND: Currently, no classification system using magnification endoscopy for the diagnosis of superficial Barrett's esophagus (BE)-related neoplasia has been widely accepted. This nationwide multicenter study aimed to validate the diagnostic accuracy and reproducibility of the magnification endoscopy classification system, including the diagnostic flowchart developed by the Japan Esophageal Society-Barrett's esophagus working group (JES-BE) for superficial Barrett's esophagus-related neoplasms. METHODS: The JES-BE acquired high-definition magnification narrow-band imaging (HM-NBI) images of non-dysplastic and dysplastic BE from 10 domestic institutions. A total of 186 high-quality HM-NBI images were selected. Thirty images were used for the training phase and 156 for the validation (test) phase. We invited five non-experts and five expert reviewers. In the training phase, the reviewers discussed how to correctly predict the histology based on the JES-BE criteria. In the validation phase, they evaluated whether the criteria accurately predicted the histology results according to the diagnostic flowchart. The validation phase was performed immediately after the training phase and at 6 weeks thereafter. RESULTS: The sensitivity and specificity for all reviewers were 87% and 97%, respectively. Overall accuracy, positive predictive value, and negative predictive value were 91%, 98%, and 83%, respectively. The overall strength of inter-observer and intra-observer agreements for dysplastic histology prediction was κ = 0.77 and κ = 0.83, respectively. No significant difference in diagnostic accuracy and reproducibility between experts and non-experts was found. CONCLUSION: The JES-BE classification system, including the diagnostic flowchart for predicting dysplastic BE, is acceptable and reliable, regardless of the clinician's experience level.

Newly developed magnifying endoscopic classification of the Japan Esophageal Society to identify superficial Barrett's esophagus-related neoplasms.

AIM AND METHODS: The Japan Esophageal Society created a working committee group consisting of 11 expert endoscopists and 2 pathologists with expertise in Barrett's esophagus (BE) and esophageal adenocarcinoma. The group developed a consensus-based classification for the diagnosis of superficial BE-related neoplasms using magnifying endoscopy. RESULTS: The classification has three characteristics: simplified, an easily understood classification by incorporating the diagnostic criteria for the early gastric cancer, including the white zone and demarcation line, and the presence of a modified flat pattern corresponding to non-dysplastic histology by adding novel diagnostic criteria. Magnifying endoscopic findings are composed of mucosal and vascular patterns, and are initially classified as "visible" or "invisible." Morphologic features were evaluated for "visible" patterns, and were subsequently rated as "regular" or "irregular," and the histology, non-dysplastic or dysplastic, was predicted. CONCLUSION: We introduce the process and outline of the magnifying endoscopic classification.

Fracture of a Colonic Self-expandable Metallic Stent in Malignant Colonic Obstruction.

Self-expandable metallic stents (SEMSs) are used for the management of malignant colorectal obstruction. A patient who underwent colonic uncovered SEMS insertion for extraluminal stenosis in the splenic flexure of the transverse colon due to advanced gastric cancer is herein reported. The patient presented with a fracture of the colonic SEMS 494 days after SEMS insertion. Although various complications of stenting have previously been reported, the details of fractures of colonic SEMSs have not yet been reported. Because the improvement in the prognosis for patients who undergo palliative SEMS insertion leads to long-term SEMS placement, diverse complications can thus be expected, and new events like stent fracture are expected to increase in the future.

Prediction of the invasion depth of superficial squamous cell carcinoma based on microvessel morphology: magnifying endoscopic classification of the Japan Esophageal Society.

Predicting invasion depth of superficial esophageal squamous cell carcinoma is crucial in determining the precise indication for endoscopic resection because the rate of lymph node metastasis increases in proportion to the invasion depth of the carcinoma. Previous studies have shown a close relationship between microvascular patterns observed by Narrow Band Imaging magnifying endoscopy and invasion depth of the superficial carcinoma. Thus, the Japan Esophageal Society (JES) developed a simplified magnifying endoscopic classification for estimating invasion depth of superficial esophageal squamous cell carcinomas. We conducted a prospective study to evaluate the diagnostic values of type B vessels in the pretreatment estimation of invasion depth of superficial esophageal squamous cell carcinomas utilizing JES classification, the criteria of which are based on the degree of irregularity in the microvascular morphology. Type A microvessels corresponded to noncancerous lesions and lack severe irregularity; type B, to cancerous lesions, and exhibit severe irregularity. Type B vessels were subclassified into B1, B2, and B3, diagnostic criteria for T1a-EP or T1a-LPM, T1a-MM or T1b-SM1, and T1b-SM2 tumors, respectively. We enrolled 211 patients with superficial esophageal squamous cell carcinoma. The overall accuracy of type B microvessels in estimating tumor invasion depth was 90.5 %. We propose that the newly developed JES magnifying endoscopic classification is useful in estimating the invasion depth of superficial esophageal squamous cell carcinoma.

A case of IgG4-related mesenteritis.

IgG4-related disease is a newly recognized fibroinflammatory condition characterized by tumefaction consisting of fibrosis with dense infiltration of IgG4-positive plasma cells; affecting various organs. A case of IgG4-related sclerosing mesenteritis is reported. A 64-year-old man was admitted to our hospital with a suspected tumor of the small intestine. Abdominal computed tomography demonstrated a 6-cm soft tissue mass in the right lower mesentery compressing the jejunum, which also showed accumulation of fluorodeoxyglucose uptake on fluorine-18 fluorodeoxyglucose positron emission tomography. With a preoperative diagnosis of suspected malignant lymphoma with lymphadenopathy in the mesentery, partial small bowel resection was performed. Macroscopically, a hard mass, including several swollen lymph nodes, was detected in the mesentery. Microscopically, marked fibrosis showing partially storiform pattern, obstructive phlebitis, follicular hyperplasia, and abundant infiltration of IgG4-positive plasma cells were detected. IgG4-related mesenteritis was diagnosed histopathologically, but the serum IgG4 level was 81 mg/dl postoperatively. Five months after the surgery, an 11-cm soft tissue mass involving the left ureter appeared. Histological examination of a biopsy specimen from the retroperitoneal mass showed fibrosis with inflammatory infiltration. Although IgG4-related retroperitoneal fibrosis could not be confirmed histologically, the tumor responded well to steroid therapy.

Organ Correlation in IgG4-Related Diseases.

IgG4-related disease (IgG4-RD) is a potentially multiorgan disorder. In this study, clinical and serological features from 132 IgG4-RD patients were compared about organ correlations. Underlying pathologies comprised autoimmune pancreatitis (AIP) in 85 cases, IgG4-related sclerosing cholangitis (IgG4-SC) in 12, IgG4-related sialadenitis (IgG4-SIA) in 56, IgG4-related dacryoadenitis (IgG4-DAC) in 38, IgG4-related lymphadenopathy (IgG4-LYM) in 20, IgG4-related retroperitoneal fibrosis (IgG4-RF) in 19, IgG4-related kidney disease (IgG4-KD) in 6, IgG4-related pseudotumor (IgG4-PT) in 3. Sixty-five patients (49%) had multiple IgG4-RD (two affected organs in 36 patients, three in 19, four in 8, five in 1, and six in 1). Serum IgG4 levels were significantly higher with multiple lesions than with a single lesion (P<0.001). The proportion of association with other IgG4-RD was 42% in AIP, the lowest of all IgG4-RDs. Serum IgG4 level was lower in AIP than in other IgG4-RDs. Frequently associated IgG4-RDs were SIA (25%) and DAC (12%) for AIP; AIP (75%) for IgG4-SC; DAC (57%), AIP (38%) and LYM (27%) for IgG4-SIA; AIP (26%) and LYM (26%) for IgG4-DAC; SIA (75%), DAC (50%) and AIP (45%) for IgG4-LYM; SIA (58%), AIP (42%) and LYM (32%) for IgG4-RF; AIP (100%) and SIA (67%) for IgG4-KID; and DAC (67%) and SIA (67%) for IgG4-PT. Most associated IgG4-RD lesions were diagnosed simultaneously, but IgG4-SIA and IgG4-DAC were sometimes identified before other lesions. About half of IgG4-RD patients had multiple IgG4-RD lesions, and some associations were seen between specific organs.

[A case of MALT lymphoma of the colon, stomach, and small intestine].

An 85-year-old man was diagnosed with mucosa-associated lymphoid tissue (MALT) lymphoma of the colon in 20XX. Although Helicobacter pylori eradication was performed as part of the treatment, it was ineffective. He was followed-up by colonoscopy for 4 years without additional treatment and there was no interval change;however, he was lost to follow-up 6 years after the first visit. Nine years after the initial diagnosis, he presented with new MALT lymphoma lesions in the stomach and small intestine. Genetic analysis showed that a biopsy specimen was positive for API2/MALT1 fusion gene, and IgH rearrangement showed monoclonal banding between colon and stomach. This suggested disseminated monoclonal API2/MALT1-positive MALT lymphoma of the colon, stomach, and small intestine. Careful attention should be paid to the appearance of multiple lesions in MALT lymphoma.

Characteristic findings of endoscopic retrograde cholangiopancreatography in autoimmune pancreatitis.

BACKGROUND/AIMS: Diffuse or segmental irregular narrowing of the main pancreatic duct (MPD), as observed by endoscopic retrograde cholangiopancreatography (ERCP), is a characteristic feature of autoimmune pancreatitis (AIP). METHODS: ERCP findings were retrospectively examined in 40 patients with AIP in whom irregular narrowing of the MPD was detected near the orifice. The MPD opening sign was defined as the MPD within 1.5 cm from the orifice being maintained. The distal common bile duct (CBD) sign was defined as the distal CBD within 1.5 cm from the orifice being maintained. Endoscopic findings of a swollen major papilla and histological findings of specimens obtained from the major papilla were examined in 26 and 21 patients, respectively. RESULTS: The MPD opening sign was detected in 26 of the 40 patients (65%). The distal CBD sign was detected in 25 of the 32 patients (78%), which showed stenosis of the lower bile duct. The patients who showed the MPD opening sign frequently showed the distal CBD sign (p=0.018). Lymphoplasmacytic infiltration, but not dense fibrosis, was histologically detected in biopsy specimens obtained from the major papilla. CONCLUSIONS: On ERCP, the MPD and CBD adjacent to the major papilla are frequently maintained in patients with AIP involving the pancreatic head. These signs are useful for diagnosing AIP on ERCP. (Gut Liver 2015;9113-117).

Major and minor duodenal papillae in autoimmune pancreatitis.

OBJECTIVE: The objective of this study was to evaluate picture of the major and minor duodenal papillae in patients with autoimmune pancreatitis (AIP). METHODS: Endoscopic features of the major and minor papillae were examined in 59 and 13 patients with AIP. After steroid therapy, changes of the major and minor papillae were observed in 5 and 6 patients. The major and minor papillae were observed with narrow band imaging in 24 and 6 patients. Biopsy specimens from the major (n = 50) and minor (n = 13) papillae were immunostained using an anti-IgG4 antibody. RESULTS: Endoscopic features of the major and minor papillae were abnormal in 26 patients (44%; swelling [n = 20] and redness [n = 14]) and 5 patients (38%; swelling [n = 5]). Swelling of the pancreatic head, irregular narrowing of the main pancreatic duct of the pancreatic head, stenosis of the lower bile duct, and abundant infiltration of IgG4-positive plasma cells were more frequent in the patients with an abnormal major papilla compared with those with a normal major papilla. On narrow band imaging, dilated vessels were observed in abnormal papillae. After therapy, swelling of the major and minor papillae improved in all 4 and 2 patients. CONCLUSIONS: Endoscopic features of the major and minor papillae were abnormal in 44% and 38% of the patients with AIP.

Allergen-specific IgE antibody serologic assays in patients with autoimmune pancreatitis.

OBJECTIVE: To clarify the allergic manifestations in patients with autoimmune pancreatitis (AIP). METHODS: We assessed 67 AIP patients, before they received steroid therapy, for a past history of allergic disease, the peripheral eosinophil count (n=62) and the serum IgE level (n=53). Allergen-specific IgE antibody serologic assays were performed in 15 patients. RESULTS: A positive past history and/or the presence of active allergic disease were found in 24 AIP patients (36%), including 15 patients with acute allergic rhinitis and eight patients with bronchial asthma. Peripheral eosinophilia and elevation of the serum IgE level were detected in 16% (10/62) and 60% (32/53) of the patients, respectively. Allergen-specific IgE antibody serologic assays were positive in 13 patients (87%). There were no differences between the assay-positive and -negative patients regarding the clinical profiles. CONCLUSION: In conclusion, 87% of the 15 AIP patients tested had positive allergen-specific IgE antibody serologic assays. Allergic mechanisms may be related to the occurrence of AIP.

Ulcerative colitis and immunoglobulin G4.

BACKGROUND/AIMS: Ulcerative colitis (UC) is sometimes associated with autoimmune pancreatitis (AIP). Infiltration of immunoglobulin G4 (IgG4)-positive plasma cells is sometimes detected in the colonic mucosa of AIP or UC patients. This study aimed to clarify the relation between UC and IgG4. METHODS: Associations with UC were reviewed in 85 AIP patients. IgG4 immunostaining was performed on biopsy specimens from the colonic mucosa of 14 AIP and 32 UC patients. RESULTS: UC was confirmed in two cases (type 1 AIP, n=1; suspected type 2 AIP, n=1). Abundant infiltration of IgG4-positive plasma cells in the colonic mucosa was detected in the case of suspected type 2 AIP with UC and two cases of type 1 AIP without colitis. Abundant infiltration of IgG4-positive plasma cells was detected in 10 UC cases (IgG4-present, 31%). Although 72% of IgG4-absent UC patients showed mild disease activity, 70% of IgG4-present patients showed moderate to severe disease activity (p<0.05). CONCLUSIONS: UC is sometimes associated with AIP, but it seems that UC is not a manifestation of IgG4-related disease. Infiltration of IgG4-positive plasma cells is sometimes detectable in the colonic mucosa of UC patients and is associated with disease activity.

Capability and limitations of recent diagnostic criteria for autoimmune pancreatitis.

Because a diagnostic serological marker is unavailable, autoimmune pancreatitis (AIP) is diagnosed based on unique features. The diagnostic capabilities and potential limitations of four sets of diagnostic criteria for AIP (Japanese diagnostic criteria 2006 and 2011, Asian diagnostic criteria, and international consensus diagnostic criteria (ICDC)) were compared among 85 patients who were diagnosed AIP according to at least one of the four sets. AIP was diagnosed in 87%, 95%, 95%, and 95% of the patients according to the Japanese 2006, Asian, ICDC, and Japanese 2011 criteria, respectively. The ICDC can diagnose types 1 and 2 AIP independently and show high sensitivity for diagnosis of AIP. However, as the ICDC are rather complex, diagnostic criteria for AIP should perhaps be revised and tailored to each country based on the ICDC.

Intraductal papillary mucinous neoplasm of the pancreas and IgG4-related disease: a coincidental association.

BACKGROUND/AIMS: Coexistence of autoimmune pancreatitis (AIP) and pancreatic cancer, elevation of serum IgG4 levels in pancreatic cancer patients, and infiltration of IgG4-positive plasma cells in peritumorous pancreatitis have been described in a few reports. This study examined the relationship between intraductal papillary mucinous neoplasm (IPMN) of the pancreas and peritumorous IgG4-positive lymphoplasmacytic infiltrates. METHODS: Serum IgG4 levels were measured in 54 patients with IPMN (median 70 years, 26 males and 28 females; 13 main duct type and 41 branch duct type). Histological findings focusing on dense lymphoplasmacytic infiltration, storiform fibrosis, and obliterative phlebitis were reviewed, and immunostaining with IgG4 and IgG was performed in 23 surgically resected IPMN cases (18 main duct type and 5 branch duct type). The presence of IgG4-positive plasma cells >10/hpf and an IgG4-positive/IgG-positive plasma cell ratio >40% were considered significant. RESULTS: Serum IgG4 levels were elevated in 2 (4%) IPMN patients. Significant infiltration of IgG4-positive plasma cells was detected in 4 IPMN cases (17%). The IgG4-positive/IgG-positive plasma cell ratio was >40% in all 4 cases. In one case with a markedly elevated serum IgG4 level (624 mg/dL), typical lymphoplasmacytic sclerosing pancreatitis (AIP type 1) lesions surrounded the whole IPMN. In the 3 other cases, infiltration of IgG4-positive plasma cells with fibrosis was focally detected mainly in the periductal area around the IPMN. CONCLUSIONS: In a few patients with IPMNs, IgG4-positive plasma cell infiltration can occur in the peritumorous area. The association of an IPMN with AIP type 1-like changes seems to be exceptional and coincidental.

Clinical features of 10 patients with IgG4-related retroperitoneal fibrosis.

OBJECTIVE: To elucidate the clinical characteristics of IgG4-related retroperitoneal fibrosis (RF). METHODS: IgG4-related RF was diagnosed when all of the following three criteria were fulfilled: retroperitoneal soft tissue masses surrounding the aorta and/or adjacent tissues, elevation of the serum IgG4 levels, and abundant infiltration of IgG4-positive plasma cells in at least one organ or site. Ten patients were diagnosed as having IgG4-related RF. RESULTS: The mean age at diagnosis was 70.1 years, and the male-to-female ratio was 1:0.6. Only two patients had initial symptoms predominantly related to RF (back pain and edema of the lower extremities), while the remaining eight patients reported initial symptoms due to associated diseases. On laboratory examination, a severe inflammatory reaction was observed in one patient. Elevation of the levels of serum IgG and IgE, eosinophilia and positivity of antinuclear antibodies were detected in seven, five, two and seven patients, respectively. The retroperitoneal masses were detected primarily in the left renal hilus in four patients, in the periaortic region in five patients and in both regions in one patient. Hydronephrosis was present in five patients. The histological diagnosis was confirmed in the retroperitoneal masses (resection, n=1 biopsy, n=2) and extraretroperitoneal lesions (n=7). Twenty-four other IgG4-related diseases were found to be associated with IgG4-related RF in nine patients (autoimmune pancreatitis (n=2), sialadenitis (n=4), dacryoadenitis (n=5), lymphadenopathy (n=9), pulmonary pseudotumor (n=1) and pituitary pseudotumor (n=1)). Seven patients underwent steroid therapy, all of whom responded well and showed no instances relapse. CONCLUSION: IgG4-related RF has several clinical characteristic features. Our diagnostic criteria may be helpful in obtaining a correct diagnosis.

Embryological aspects in autoimmune pancreatitis, proposal of autoimmune dorsal pancreatitis.

OBJECTIVE: We examined the anatomy of the pancreatic duct system in patients with autoimmune pancreatitis (AIP) from the standpoint of embryological pancreatic primordial. MATERIAL AND METHODS: The pancreatic duct system involved in 83 AIP patients was embryologically divided into both ventral and dorsal pancreatic ducts (VD type), only the dorsal pancreatic duct (D type), or only the ventral pancreatic duct (V type). RESULTS: The 83 AIP patients were divided into 62 VD type, 20 D type, and 1 V type. Obstructive jaundice was significantly more frequent in VD type (87%) than in D type (0%; p < 0.01), and abdominal pain was more frequent in D type (24%) than in VD type (2%; p < 0.01). Stenosis of the lower bile duct was detected in 98% of VD type and 15% of D type (p < 0.01). In the 67 patients with involvement of the pancreatic head, only the dorsal pancreatic duct was involved with a normal ventral pancreatic duct in four patients (D type). In the four D-type patients, the pancreatic duct system showed complete pancreas divisum (n = 1), incomplete pancreas divisum (n = 2), or normal pancreatic duct system (n = 1). Stenosis of the lower bile duct was seen in three patients, but was mild, resulting in no obstructive jaundice. Three patients reported abdominal pain and one patient developed acute pancreatitis. CONCLUSIONS: We propose a new entity of "autoimmune dorsal pancreatitis" in which only the dorsal pancreas is involved, and involvement of the lower bile duct and obstructive jaundice is rare.

Differentiating immunoglobulin g4-related sclerosing cholangitis from hilar cholangiocarcinoma.

BACKGROUND/AIMS: Few studies have differentiated immunoglobulin G (IgG) 4-related sclerosing cholangitis (IgG4-SC) from hilar cholangiocarcinoma (CC). Thus, we sought to investigate useful features for differentiating IgG4-SC from hilar CC. METHODS: We retrospectively compared clinical, serological, imaging, and histological features of six patients with IgG4-SC and 42 patients with hilar CC. RESULTS: In patients with hilar CC, obstructive jaundice was more frequent (p<0.01), serum total bilirubin levels were significantly higher (p<0.05), serum CA19-9 levels were significantly higher (p<0.01), and serum duke pancreatic monoclonal antigen type 2 levels were frequently elevated (p<0.05). However, in patients with IgG4-SC, the serum IgG (p<0.05) and IgG4 (p<0.01) levels were significantly higher and frequently elevated. The pancreas was enlarged in all IgG4-SC patients but only in 17% of hilar CC patients (p<0.01). Salivary and/or lacrimal gland swelling was detected in only 50% of IgG4-SC patients (p<0.01). Endoscopic retrograde cholangiography revealed that the hilar or hepatic duct was completely obstructed in 83% of hilar CC patients (p<0.01). Lower bile duct stenosis, apart from hilar bile duct stenosis, was more frequent in IgG4-SC patients (p<0.01). Bile duct wall thickening in areas without stenosis was more frequent in IgG4-SC patients (p<0.01). CONCLUSIONS: An integrated diagnostic approach based on clinical, serological, imaging, and histological findings is necessary to differentiate IgG4-SC from hilar CC.

Pancreatic cancer causing acute pancreatitis: a comparative study with cancer patients without pancreatitis and pancreatitis patients without cancer.

BACKGROUND/PURPOSE: Although pancreatic cancer produces upstream obstructive pancreatitis, acute pancreatitis is a less common manifestation of pancreatic cancer. This study aimed to clarify the subgroup of pancreatic cancer patients who present with an episode of acute pancreatitis (Group I) in comparison with a matched group of pancreatic cancer patients without pancreatitis (Group II) and another group of acute pancreatitis patients without pancreatic cancer (Group III). METHODS: This was a retrospective comparative study of 18 patients in Group I, 300 patients in Group II and 141 patients in Group III. RESULTS: The mean age of Group I was 63.7 years and the male to female ration was 1:0.3. Serum CA 19-9 levels were elevated in 80 %. The main pancreatic duct was incompletely obstructed in 7 patients. There were no significant differences in location of tumor, clinical stage, resection rate and survival months between Group I and II. Acute pancreatitis secondary to pancreatic cancer was more likely to be mild (94 vs. 72 %,p < 0.05) and relapsed (39 vs. 16 %,p < 0.05) compared with Group III. CONCLUSIONS: Anatomic evaluation of the pancreas should be performed in patients with acute pancreatitis with no obvious etiology, even if the pancreatitis is mild, to search for underlying malignancy.