Clinical utility of artificial intelligence assistance in histopathologic review of lymph node metastasis for gastric adenocarcinoma.

BACKGROUND: Advances in whole-slide image capture and computer image analyses using deep learning technologies have enabled the development of computer-assisted diagnostics in pathology. Herein, we built a deep learning algorithm to detect lymph node (LN) metastasis on whole-slide images of LNs retrieved from patients with gastric adenocarcinoma and evaluated its performance in clinical settings. METHODS: We randomly selected 18 patients with gastric adenocarcinoma who underwent surgery with curative intent and were positive for LN metastasis at Chiba University Hospital. A ResNet-152-based assistance system was established to detect LN metastases and to outline regions that are highly probable for metastasis in LN images. Reference standards comprising 70 LN images from two different institutions were reviewed by six pathologists with or without algorithm assistance, and their diagnostic performances were compared between the two settings. RESULTS: No statistically significant differences were observed between these two settings regarding sensitivity, review time, or confidence levels in classifying macrometastases, isolated tumor cells, and metastasis-negative. Meanwhile, the sensitivity for detecting micrometastases significantly improved with algorithm assistance, although the review time was significantly longer than that without assistance. Analysis of the algorithm's sensitivity in detecting metastasis in the reference standard indicated an area under the curve of 0.869, whereas that for the detection of micrometastases was 0.785. CONCLUSIONS: A wide variety of histological types in gastric adenocarcinoma could account for these relatively low performances; however, this level of algorithm performance could suffice to help pathologists improve diagnostic accuracy.

Comparison of the risk of ovarian malignancy algorithm and Copenhagen Index for the preoperative assessment of Japanese women with ovarian tumors.

OBJECTIVE: To compare the risk of ovarian malignancy algorithm (ROMA) and Copenhagen Index (CPH-I) in their ability to distinguish epithelial ovarian cancer (EOC) and malignant ovarian tumors (MLOT) from benign ovarian tumors (BeOT) in Japanese women. METHODS: Patients with pathologically diagnosed ovarian tumors were included in this study. The study validated the diagnostic performance of ROMA and CPH-I. RESULTS: Among the 463 Japanese women included in this study, 312 had BeOT, 99 had EOC, and 52 had other MLOT. The receiver-operator characteristic (ROC) area under the curve (AUCs) of ROMA (0.89) and CPH-I (0.89) for distinguishing EOC from BeOT were significantly higher than that of CA125 (0.82) (CA 125 vs. ROMA; p = 0.002, vs. CPH-I; p < 0.001). The ROC-AUCs of ROMA (0.82) and CPH-I (0.81) for distinguishing MLOT from BeOT were significantly higher than that of CA125 (0.75) (CA 125 vs. ROMA: p = 0.003, vs. CPH-I: p < 0.001). The sensitivity (SN)/specificity (SP) of ROMA and CPH-I for distinguishing EOC from BeOT at standard cut-off points were 69%/90%, and 69%/90%, respectively, those for distinguishing MLOT from BeOT were 54%/90%, and 55%/90%, respectively. CONCLUSION: ROMA and CPH-I performed comparably well and better than CA125 in distinguishing EOC from BeOT in Japanese women. ROMA and CHP-I should be used with caution in practical situations, where all histological possibilities for must be considered, because the SNs of ROMA and CPH-I were only 54% and 55%.

Hepatic invasion of a gastric ulcer confirmed by endoscopy and surgery.

A 66-year-old woman who had been suffering from chronic anorexia for two years was transported to the hospital after being unable to consume food for three days. She had no hematemesis or abdominal pain and had no history of taking nonsteroidal anti-inflammatory drugs. Blood tests showed marked anemia with hemoglobin of 3.3 g/dL, and esophagogastroduodenoscopy revealed a large ulcer lesion in the lesser curvature of the gastric body and a liver-like mass protruding from the ulcer base. Biopsy of the mass showed proliferation of cells showing irregular cord-like structures, suggestive of normal liver tissue or hepatocellular carcinoma. Computed tomography scan showed no obvious free air in the abdomen. Despite conservative treatment, the patient developed hematemesis and progressive anemia, and surgery was performed (total gastrectomy with partial hepatectomy). Surgical specimen showed an ulcer lesion with fibrosis and loss of wall structure in all layers of the stomach, and liver adhesion with fibrosis deep in the ulcer, but no malignant findings. With the advent of powerful gastric acid secretion inhibitors, gastric ulcer invasion into the liver is now very rare, and this case is thus a valuable example showing very clear images.

Cerebellar tonsillar herniation in sudden death of an adolescent anorexia nervosa patient: a case report.

BACKGROUND: Anorexia nervosa not only results in severe malnutrition but also carries a high risk of sudden death. Although fatal arrhythmias are the most common cause of sudden death, it is often unclear what exactly causes them. To the best of our knowledge, there have been no reports of cerebellar tonsillar herniations in patients with anorexia nervosa. CASE PRESENTATION: A 17-year-old girl with anorexia nervosa and autism spectrum disorder was admitted to the pediatric ward for extreme weight loss. Since she refused to take oral nutrition or tube feeding, we started continuous intravenous fluids. Eight hours after admission, she suddenly went into cardiopulmonary arrest and died despite resuscitation. A postmortem autopsy revealed the unexpected findings of generalized severe cerebral edema and cerebellar tonsillar herniation. CONCLUSION: Intracranial hypertension may need to be considered when the condition of patients with anorexia nervosa suddenly worsens during refeeding periods. Postmortem autopsy and autopsy imaging are recommended to determine the exact cause of sudden death. LEVEL OF EVIDENCE: Level IV: Evidence obtained from multiple time series analysis such as case studies. (NB: Dramatic results in uncontrolled trials might also be regarded as this type of evidence).

Myxoid stroma is associated with postoperative relapse in patients with stage II colon cancer.

BACKGROUND: Fibrosis surrounding cancer cells has been shown to affect cancer cell metastatic behavior. The present study aimed to explore the utility of myxoid stroma as a predictive factor for postoperative relapse in patients with stage II colon cancer. METHODS: The present study retrospectively investigated 169 patients who underwent curative surgical resection of stage II colon cancer. The fibrotic stroma was classified according to Ueno's criteria, and the patients were divided into the myxoid (MY) group and the non-MY (NMY) group. We also recorded tumor budding (TB) and investigated the combination of MY and TB for postoperative relapse. Postoperative survival was also explored. RESULTS: Thirty-two (18.9%) patients had MY. MY was significantly associated with tumor budding (TB) and postoperative relapse (p <  0.001 and p <  0.001, respectively). The 5-year RFS rates in MY group and NMY group were 52.1 and 94.6% (p < 0.0001), and the 5-year OS rates in MY group and NMY group were 74.6 and 93.3% (p = 0.001). Multivariate analysis showed that both MY and TB were significant risk factors for postoperative relapse (p < 0.001 and p = 0.02, respectively), and that only TB was a significant risk factor for OS (p = 0.043). Furthermore, compared with patients with either one of MY or TB, patients with both MY and TB had postoperative relapse more frequently (11.4% vs. 53.8%). CONCLUSIONS: The present study suggests that MY is a predictive marker for postoperative relapse in patients with stage II colon cancer.

The origin of p40-negative and CDX2-positive primary squamous cell carcinoma of the stomach: case report.

BACKGROUND: Primary gastric squamous cell carcinoma (SCC) is a very rare disease. The origin of this tumor remains unclear, although there are some hypotheses. A 60-year-old man consulted a previous physician complaining of upper abdominal pain. Esophagogastroduodenoscopy revealed type 2 gastric cancer, and the patient was referred to our hospital. After close examination, the patient was diagnosed as cStage IIA gastric adenocarcinoma, and distal gastrectomy was performed. Histochemical studies showed typical findings of SCC, and the tumor was surrounded by intestinal metaplasia. Immunohistochemical examination was positive for cytokeratin (CK) 5/6 and caudal-type homeobox protein 2 (CDX2) and negative for p63/p40. CONCLUSION: The results of immunostaining for CK5/6 supported that this tumor was SCC, but the question why p63/p40 were negative and CDX2 was positive still remained. Concerning about the origin of p63/p40 and CDX2, it was suggested that the tumor cells were not derived from ectopic squamous epithelium but from intestinal metaplasia. And tumor cells looked like homogeneous and squamous metaplasia was not observed. These findings supported the idea that these tumor cells arose from stem cells in the intestinal metaplasia of the stomach.

Gastric mucosal status susceptible to lanthanum deposition in patients treated with dialysis and lanthanum carbonate.

Lanthanum carbonate is a popular chemical which is administered for patients with end-stage kidney disease to reduce the absorption of phosphate, and lanthanum deposition in the gastroduodenal mucosa has recently been reported. The aim of this study was to assess whether any histologic changes of the gastric mucosa are related to the deposition of lanthanum. Twenty-four patients who revealed the histology of lanthanum deposition on gastroduodenal biopsy between 2011 and 2014 were included in the study, and their clinical records and gastroduodenal biopsies obtained from 2011 to 2015 were reviewed, adding the review of gastroduodenal biopsies before 2011 if possible. Analysis of the deposited materials by scanning electron microscopy-energy dispersive x-ray spectroscopy was performed for a representative gastric biopsy. All patients were diagnosed as having renal insufficiency due to chronic kidney disease and treated with dialysis for more than 5 years, with confirmation of lanthanum carbonate use for 22 patients. Of 121 gastric biopsies and 10 duodenal ones between 2011 and 2015, 86 gastric biopsies (71.1%) and 3 duodenal biopsies (30%), respectively, revealed histology consistent with lanthanum deposition, which was confirmed by scanning electron microscopy-energy dispersive x-ray spectroscopy analysis for a representative case. The deposition tended to occur in the gastric mucosa with regenerative change, intestinal metaplasia, or foveolar hyperplasia (P<.05). Such mucosal changes were observed in about half of the gastric biopsy samples obtained prior to 2010, in which no lanthanum deposition was identified irrespective of the gastric mucosal status. Although direct association between lanthanum deposition and clinical symptoms is not clear, the evaluation of the gastric mucosal status (prior to administration) seems to be important to predict lanthanum deposition when lanthanum carbonate is administered for patients with chronic kidney disease treated with dialysis.

Development of a new classification for in vivo diagnosis of duodenal epithelial tumors with confocal laser endomicroscopy: A pilot study.

BACKGROUND AND AIM: Confocal laser endomicroscopy (CLE) has been established for in vivo diagnosis of various gastrointestinal diseases. However, validated criteria for confocal diagnosis of duodenal tumors do not exist. Therefore, the aim of the present pilot study was to develop a novel classification for in vivo optical diagnosis of duodenal tumors using CLE. METHODS: Consecutive patients with duodenal tumorous lesions were included. First, an initial classification system was developed which was then validated. Histopathology was used as a reference standard. RESULTS: A simple classification system for in vivo diagnosis of duodenal epithelial tumors using CLE was developed. Sensitivity, specificity, and accuracy were 90%, 100%, and 97%, respectively. Positive and negative predictive values were calculated as 100% and 96%. The kappa coefficient representing consistency was 1 between observers and within each observer. CONCLUSION: A new classification for in vivo diagnosis of duodenal epithelial tumors using confocal imaging has been developed. The new classification system allows adequate prediction of histology and could therefore be used to guide subsequent therapy of duodenal lesions.

Adenocarcinoma arising in small sessile serrated adenoma/polyp (SSA/P) of the colon: clinicopathological study of eight lesions.

We reviewed the clinicopathological findings of eight cases of sessile serrated adenoma/polyps (SSA/Ps) with carcinoma, the largest diameter of which was 10 mm or less. All lesions were polyps located in the right side of the colon. Four lesions showed submucosal invasion and one lesion invaded the proper muscle layer. The depth of invasion, however, did not seem to be related to the carcinoma area size. Most carcinomas were well to moderately differentiated tubular adenocarcinomas focally showing some serrated appearances, and the predominant component of one carcinoma was a poorly differentiated medullary growth with inflammatory stroma. Rapid progression to invasive carcinoma from SSA/P was suggested for the carcinoma with proper muscle invasion whereas one submucosally invasive carcinoma was considered to progress over 7 years. Immunohistochemically, it was suggested that with or without hMLH1 protein loss, alterations of p53 and/or Wnt signaling pathway can be involved in the cancerization through SSA/Ps. The carcinomas irregularly imitated the mucin expression of the SSA/Ps (positive for MUC5AC and MUC2, and MUC6 expression in crypt bases), which was lost with progression of the carcinomas. Analyses of small SSA/P lesions with cancerization would facilitate the understanding of the mode of progression of SSA/Ps and their early detection.

Two tumor types in a unilateral testis in a patient with severe oligozoospermia and a history of cryptorchidism surgery: A case report.

Testicular cancer, the most common cancer among young male adults, is associated with infertility. A 38-year-old male patient was admitted to Dokkyo Medical University Saitama Medical Center, Japan, with infertility associated with severe oligozoospermia. Scrotal ultrasonography revealed two distinct tumors in the left testis: A mass with abundant blood flow on the cranial side and a mass with poor blood flow on the caudal side. Additional analysis revealed mild elevation of intact human chorionic gonadotropin (hCG) levels (tumor marker level assessment), high testosterone and low luteinizing hormone and follicle-stimulating hormone levels (hormonal level assessment) and severe oligoasthenozoospermia (semen assessment). The preoperative diagnosis was left-sided testicular cancer and severe oligoasthenozoospermia and the patient underwent left high orchiectomy and oncological testicular sperm extraction. Based on the pathological assessment, the cranial tumor was diagnosed as a seminoma with syncytiotrophoblastic cells, whereas the caudal tumor had only scar tissue with germ cell neoplasia in situ in the adjacent parenchyma. Following surgery, intact hCG and hormone levels of the patient were normalized, and the semen parameters (semen volume, sperm density, and motility) improved dramatically. To the best of our knowledge, the present case is the first report of two types of testicular tumor in a unilateral testis in a patient with a history of cryptorchidism surgery. The present case demonstrated that scrotal ultrasonography should be performed in patients with abnormal semen results to rule out testicular tumors.

A Case of a Granular Cell Tumor Arising in a Patient with Long-segment Barrett's Esophagus.

Esophageal cell tumors are rare. Esophagogastroduodenoscopy performed on a 48-year-old woman revealed an elevated esophageal lesion and the presence of long-segment Barrett's esophagus. Endoscopic ultrasonography showed a 15 mm homogeneous hypoechoic tumor extending from the lamina propria mucosa to the submucosa. Pathological examination of the biopsy tissue revealed a sheet-like cluster of histiocytoid cells with an abundant eosinophilic granular cytoplasm. Immunohistochemical examination revealed S-100 (+) and CD68 (+), thus suggesting the diagnosis of a granular cell tumor. The tumor was resected by endoscopic submucosal dissection. Pathologically, the background mucosa was Barrett's mucosa. This is the first reported case of an esophageal granular cell tumor in long-segment Barrett's esophagus.

Primary anastomosing hemangioma as a preoperative diagnostic mimicker of retroperitoneal cavernous hemangioma: A case report.

Anastomosing hemangioma (AH) is rare and a newly recognized variant of capillary hemangioma that is mostly found in the genitourinary tract. Additionally, AH is sometimes difficult to diagnose without pathological specimens. It is difficult to diagnose preoperatively due to the lack of specific clinical and radiologic appearance. The present report describes the imaging features from a radiological perspective and outlines the clinicopathologic features and treatment options. A 67-year-old woman was referred to Dokkyo Medical University Saitama Medical Center (Koshigaya, Japan) for a retroperitoneal tumor that was identified at a medical checkup 4 years prior. The patient had no symptoms, no abnormal physical signs and no past medical or specific family history. Routine blood tests were all within the normal ranges. A nonenhanced CT scan showed a circular, homogenous, well-circumscribed retroperitoneal tumor that was ~32×23 mm in size, between the abdominal aorta and the inferior vena cava, and just below the left renal vein. On a contrast-enhanced multidetector CT scan, the tumor showed heterogeneous septal enhancement in the arterial phase and persistent enhancement in the portal phase. The tumor was diagnosed as a benign neurogenic tumor or a retroperitoneal cavernous hemangioma at the time, and the patient was intended to be followed up at the outpatient clinic. However, it gradually increased to a maximum diameter of 35 mm over 4 years. Finally, it was completely resected by open laparotomy and pathologically diagnosed as AH. Retroperitoneal hemangioma is extremely rare in adulthood and has been confirmed in only 1-3% of all retroperitoneal tumors. To the best of our knowledge, only 6 cases of para-aortic AH have been reported. The incidence of this variant is very low. However, AH may be included in the differential diagnosis when a slowly progressing heterogeneous mass appears in the para-aortic region that exhibits a CT-enhanced pattern similar to a typical cavernous hemangioma.

Very well-differentiated gastric carcinoma of intestinal type: analysis of diagnostic criteria.

Very well-differentiated gastric adenocarcinoma of intestinal type is a rare variant of gastric cancer characterized by low-grade nuclear atypia, and for which the diagnostic criteria and clinical behavior are not fully established. This study presents a detailed histologic, immunohistochemical, and clinical analysis of 21 cases. Nuclear atypia was mild in all cases. Characteristic architectural features of this gastric adenocarcinoma variant were pit and glandular anastomosis, spiky glands, distended glands, discohesive cells, abortive glands, and glandular outgrowth. At least three of these features were present in all the cases. Retrospective review of preoperative biopsies in 18 patients revealed that half of the biopsies were originally reported as negative or indeterminate for malignancy. On the basis of immunohistochemical stains for intestinal (MUC2, CD10, and CDX-2) and gastric (MUC5AC and MUC6) markers, 11 (52%) cases had an intestinal immunophenotype and 10 (48%) cases had a mixed immunophenotype. Foci of discohesive neoplastic cells, indicating dedifferentiation toward a poorly cohesive carcinoma, were observed exclusively in neoplasms of mixed immunophenotype (n=5). All patients with follow-up but one were alive without disease at a mean of 19 months (range 1-60 months). One individual with a pT4 tumor with associated poorly cohesive carcinoma died of disease. In summary, very well-differentiated gastric adenocarcinomas are diagnostically challenging. Architectural features are critical to making the diagnosis. Cases with pure intestinal immunophenotype have not been associated with transformation into poorly cohesive carcinoma, and appear to behave as biologically low grade. Those with mixed immunophenotype appear more likely to dedifferentiate and behave more aggressively.

Different healing process of esophageal large mucosal defects by endoscopic mucosal dissection between with and without steroid injection in an animal model.

BACKGROUND: Stricture formation is one of the major complications after endoscopic removal of large superficial squamous cell neoplasms of the esophagus, and local steroid injections have been adopted to prevent it. However, fundamental pathological alterations related to them have not been well analyzed so far. The aim of this study was to analyze the time course of the healing process of esophageal large mucosal defects resulting in stricture formation and its modification by local steroid injection, using an animal model. METHODS: Esophageal circumferential mucosal defects were created by endoscopic mucosal dissection (ESD) for four pigs. One pig was sacrificed five minutes after the ESD, and other two pigs were followed-up on endoscopy and sacrificed at the time of one week and three weeks after the ESD, respectively. The remaining one pig was followed-up on endoscopy with five times of local steroid injection and sacrificed at the time of eight weeks after the ESD. The esophageal tissues of all pigs were subjected to pathological analyses. RESULTS: For the pigs without steroid injection, the esophageal stricture was completed around three weeks after the ESD on both endoscopy and esophagography. Histopathological examination of the esophageal tissues revealed that spindle-shaped α-smooth muscle actin (SMA)-positive myofibroblasts arranged in a parallel fashion and extending horizontally were identified at the ulcer bed one week after the ESD, and increased contributing to formation of the stenotic luminal ridge covered with the regenerated epithelium three weeks after the ESD. The proper muscle layer of the stricture site was thinned with some myocytes which seemingly showed transition to the myofibroblast layer. By contrast, for the pig with steroid injection, esophageal stricture formation was not evident with limited appearance of the spindle-shaped myofibroblasts, instead, appearance of stellate or polygocal SMA-positive stromal cells arranged haphazardly in the persistent granulation tissue of the ulcer site. CONCLUSIONS: Proliferation of spindle-shaped myofibroblasts arranged in a parallel fashion is likely to play an important role in stricture formation after circumferential mucosal defects by esophageal ESD, which may be related to the thinning of the proper muscle layer in the healing course of the defects. Local steroid injection seems to be effective to prevent the stricture through the modification of this process.

Aberrant cytokeratin expression as a possible prognostic predictor in poorly differentiated colorectal carcinoma.

BACKGROUND AND AIM: The cytokeratin (CK)7(-) /CK20(+) immunoprofile is characteristic of colorectal carcinoma (CRC), although CK7(+) or CK20(-) phenotypes are occasionally encountered, particularly in histologically variant CRCs. We analyzed CK7/CK20 profiles in variant CRCs in association with clinicopathologic parameters and prognosis. METHODS: CK expression in well- and moderately differentiated adenocarcinoma (WMDA) (n = 63), poorly differentiated adenocarcinoma (PDA) (n = 91), mucinous adenocarcinoma (MUA) (n = 81), signet-ring cell carcinoma (SRCC) (n = 15), undifferentiated carcinoma (UDC) (n = 12), and adenosquamous carcinoma (n = 2) was analyzed using immunohistochemistry. Cut-off scores were set at 1% for CK7 and 25% for CK20 using the receiver operating characteristic curve analysis of PDA. Association between CK20(-) and better prognosis in PDA was validated in the second cohort (n = 66). RESULTS: CK7/CK20 immunoprofiling revealed a predominant CK7(-) /CK20(+) profile in WMDA, MUA, and SRCC, while the majority of UDC was characterized by a CK7(-) /CK20(-) profile. The CK7/CK20 profile in PDA was variable. Contingency table analysis revealed that CK expression was not significantly associated with any clinicopathologic parameters in WMDA, PDA, and MUA. However, survival analysis demonstrated that CK20(-) was significantly associated with better prognosis in PDA. Although CK20(-) was significantly associated with mismatch repair deficiency in PDA, it was an independent prognostic factor in multivariate analysis. Finally, we confirmed that CK20 status, determined using a 25% cut-off score, was a significant prognostic parameter in the second PDA cohort. CONCLUSIONS: CK20 status may be used as a prognostic predictor of PDA.

A case of eosinophilic pancreatitis in a patient with ulcerative colitis.

Eosinophilic pancreatitis (EP) is very rare and characterised by infiltration of eosinophils into the pancreatic parenchyma. A 40-year-old man was diagnosed with total-colitis-type ulcerative colitis at the age of 15 years. He was then diagnosed with steroid-dependent ulcerative colitis. He was given golimumab, which resulted in remission. Ten months after beginning golimumab, he was urgently hospitalised with a diagnosis of acute pancreatitis. Hence, endoscopic ultrasound-guided fine needle biopsy was performed to obtain a definitive diagnosis. Pathologically, abundant infiltration of eosinophils was observed in the edematous intralobular stroma of the pancreas. He was diagnosed with EP, and treated with corticosteroids.

Duodenal gastric-type neoplasm with uncertain malignant potential in a lipoma.

The pathologic diagnosis of duodenal tumors is a developing field; however, its overview remains unclear. We describe a rare case of a duodenal gastric-type neoplasm in a 50-year-old woman. She visited her primary care doctor with complaints of upper abdominal pain, tarry stools, and shortness of breath on exertion. She was admitted owing to a stalked polyp with erosion and hemorrhage in the descending part of the duodenum. Endoscopic mucosal resection (EMR) was performed on the polyp. Histologically, the resected polyp was a lipomatous lesion in the submucosal layer, composed of mature adipose tissues. Scattered irregular lobules of Brunner's gland-like structures with well-preserved construction but mildly enlarged nuclei and occasional conspicuous nucleoli of the constituent cells were observed. The resection margin was negative. EMR findings of the duodenal polyp showed a gastric epithelial tumor within a lipoma, a rare histological type that has not been reported previously. This tumor may be classified as a "neoplasm with uncertain malignant potential" in a lipoma, an intermediate category between adenoma and invasive adenocarcinoma. There is no consensus on treatment, and careful follow-up is recommended. This is the first report of a duodenal gastric-type neoplasm with uncertain malignant potential in a lipoma.

Endoscopic Treatment for Submucosal Heterotopic Gastric Gland in a Case Observed over Nine Years from Development to Enlargement.

A 70-year-old Japanese man with a submucosal gastric mass that continued to increase in size underwent endoscopic submucosal dissection using the pocket creation method. Histologically, some epithelial cell nuclei were enlarged, but there was little atypia overall and no sign of malignancy, suggesting a diagnosis of submucosal heterotopic gastric gland (SHGG). SHGG that enlarges over time has been associated with gastric cancer, but a preoperative diagnosis is difficult. This case was very valuable, as it enabled us to follow the course of SHGG over a period of about nine years, from the onset to enlargement.

Prognostic relevance of morphological types of intraductal papillary mucinous neoplasms of the pancreas.

OBJECTIVE: The clinicopathological significance of four morphological types of intraductal papillary mucinous neoplasms of the pancreas (IPMNs; gastric, intestinal, pancreatobiliary and oncocytic) was assessed. DESIGN: Retrospective multicentre analysis of 283 surgically resected IPMNs. RESULTS: Of the 283 IPMNs, 139 were of the gastric type, 101 were intestinal, 19 were pancreatobiliary and 24 were oncocytic. These types were significantly associated with clinicopathological factors including sex (p = 0.0032), age (p = 0.00924), ectatic duct size (p = 0.0245), detection of mural nodules (p = 4.09 × 10⁻6), histological grade (p < 2.20 × 10⁻¹6), macroscopic types with differential involvement of the pancreatic duct system (p = 3.91 × 10⁻5), invasive phenotypes (p = 3.34 × 10⁻¹²), stage (p < 2.20 × 10⁻¹6) and recurrence (p = 0.00574). Kaplan-Meier analysis showed significant differences in patient survival by morphological type (p = 5.24 × 10⁻6). Survival rates at 5 and 10 years, respectively, were 0.937 (95% CI 0.892 to 0.984) for patients with gastric-type IPMNs; 0.886 (95% CI 0.813 to 0.965) and 0.685 (95% CI 0.553 to 0.849) for those with intestinal-type IPMNs; 0.839 (95% CI 0.684 to 1.000) and 0.734 (95% CI 0.526 to 1.000) for those with oncocytic-type IPMNs; and 0.520 (95% CI 0.298 to 0.909) and undetermined for those with pancreatobiliary-type IPMNs. Analysis by the Cox proportional hazards model comparing prognostic risks determined by stage and the morphological and macroscopic types indicated that staging was the most significant predictor of survival (p = 3.68×10⁻8) followed by the morphological type (p = 0.0435). Furthermore, the morphological type remained a significant predictor in a subcohort of invasive cases (p = 0.0089). CONCLUSION: In this multicentre retrospective analysis, the morphological type of IPMN appears to be an independent predictor of patient prognosis.