Cost-effectiveness of operative intervention for mucinous cystic neoplasm: the role of post-operative diabetes.

BACKGROUND: Small mucinous cystic neoplasms (MCN) of the pancreas are managed with operative resection in otherwise healthy patients; however, postoperative diabetes development is not considered in recommendations for resection. METHODS: Via probabilistic microsimulation Markov modeling, we assessed clinical and economic implications of laparoscopic distal pancreatectomy (LDP) versus surveillance for non-DM patients with suspected MCN of 2 cm without high-risk or worrisome features. Primary outcomes included quality-adjusted life years (QALYs), medical costs (2021 USD), and incremental cost-effectiveness ratios (ICERs). We conducted sensitivity analyses to evaluate the robustness of our model to changes in input parameters. All analyses were repeated for a population with pre-DM. RESULTS: Surveillance resulted in 6.52 QALYs and $61,200, while LDP accumulated 6.12 QALYs and $63,700. Almost 20% of the LDP cohort developed DM over the first 10 years, compared to 11% of the surveillance cohort. In a pre-DM cohort, LDP remained Dominated in the base case, with over 40% developing DM postoperatively. In sensitivity analyses, surveillance remained the preferred strategy in most iterations for both cohorts. CONCLUSIONS: Surveillance for small suspected MCNs without high-risk features is the preferred strategy from a clinical and economic standpoint. Consensus guidelines should consider the long-term implications of postoperative diabetes development following LDP.

Significance of Specimen Extraction Site in Minimizing Hernia Risk After Distal Pancreatectomy.

BACKGROUND: Incisional hernia (IH) results in significant morbidity to patients and financial burden to healthcare systems. We aimed to determine the incidence of IH in distal pancreatectomy (DP) patients, stratified by specimen extraction sites. METHOD: Imaging in DP patients in our institution from 2016 to 2021 were reviewed by radiologists blinded to the operative approach. Specimen extraction sites were stratified as upper midline/umbilical (UM) versus Pfannenstiel. IH was defined as fascial defect on postoperative imaging. Patients without preoperative and postoperative imaging were excluded. RESULTS: Of the 219 patients who met our selection criteria, the median age was 64 years, 54% were female, and 64% were White. The majority were minimally invasive (MIS) procedures (n = 131, 60%), of which 52% (n = 64) had a UM incision for specimen extraction, including 45 hand-assist and 19 purely laparoscopic procedures. MIS with Pfannenstiel incisions for specimen extraction was 48% (n = 58), including 44 robotic and 14 purely laparoscopic procedures. Mean follow-up time was 16.3 months (standard deviation [SD] 20.8). Follow-up for MIS procedures with UM incisions was 16.6 months (SD 21.8) versus 15.5 months (SD 18.6) in the Pfannenstiel group (p = 0.30). MIS procedures with UM incisions for specimen extraction had a 17.8 times increase in odds of developing an IH compared with MIS procedures with Pfannenstiel extraction sites (p = 0.01). The overall odds of developing an IH increased by 4% for every month of follow-up (odds ratio 1.04; p < 0.001). CONCLUSION: A Pfannenstiel incision should be performed for specimen extraction in cases with purely laparoscopic or robotic distal pancreatectomy, when feasible.

Long-term symptom resolution following the surgical management of chronic pancreatitis.

BACKGROUND: Pervasive symptoms from chronic pancreatitis despite noninvasive management is an indication for surgical intervention. Frey and Whipple procedures are appropriate options for proximal pancreas disease; however, data are limited on symptomatic outcomes. METHODS: We conducted a retrospective analysis of patients who underwent surgical intervention for chronic pancreatitis of the proximal pancreas from 2005 to 2019. Preoperative patient characteristics and postoperative outcomes were evaluated. RESULTS: One hundred forty patients underwent surgical intervention for chronic pancreatitis, 91 Whipple and 49 Frey procedures. Mean age was 53 years (SD 12), and mean BMI 24 (SD 5.6). At post-operative follow-up, 74 â€‹% were asymptomatic, and 84 â€‹% at average follow-up of 2 years. Groove pancreatitis, lack of post-operative delayed gastric emptying, and decreased length of stay were predictive of symptom resolution. CONCLUSIONS: Whipple and Frey procedures are appropriate surgical options for chronic pancreatitis affecting the proximal pancreas. Both lead to sustained symptom resolution for most patients.

Differences in preoperative frailty assessment of surgical candidates by sex, age, and race.

Introduction: Surgical decision-making often relies on a surgeon's subjective assessment of a patient's frailty status to undergo surgery. Certain patient demographics can influence subjective judgment when compared to validated objective assessments. In this study, we explore the relationship between subjective and objective frailty assessments according to patient age, sex, and race. Methods: Patients were prospectively enrolled in urology, general surgery, and surgical oncology clinics. Using a visual analog scale (0-100), operating surgeons independently rated the patient's frailty status. Objective frailty was classified using the Fried Frailty Criteria ranging from 0 to 5. Multivariable proportional odds models were conducted to examine the potential association of factors with objective frailty, according to surgeon frailty rating. Subgroup analysis according to patient sex, race, and age was also performed. Results: Seven male surgeons assessed 203 patients preoperatively with a median age of 65. A majority of patients were male (61 %), white (67 %), and 60 % and 40 % underwent urologic and general surgery/surgical oncology procedures respectively. Increased subjective surgeon rating (OR 1.69; p < 0.001) was significantly associated with the presence of objective frailty. On subgroup analysis, a higher magnitude of such association was observed more in females (OR 1.86; p = 0.0007), non-white (OR 1.84; p = 0.0019), and older (>60, OR 1.75; p = 0.0001) patients, compared to male (OR 1.45; p = 0.0243), non-white (OR 1.48; p = 0.0109) and patients under 60 (OR 1.47; p = 0.0823). Conclusion: The surgeon's subjective assessment of frailty demonstrated tendencies to rate older, female, and non-white patients as frail; however, differences in patient sex, age, and race were not statistically significant.

Transposon DNA sequences facilitate the tissue-specific gene transfer of circulating tumor DNA between human cells.

The exchange of genes between cells is known to play an important physiological and pathological role in many organisms. We show that circulating tumor DNA (ctDNA) facilitates cell-specific gene transfer between human cancer cells and explain part of the mechanisms behind this phenomenon. As ctDNA migrates into the nucleus, genetic information is transferred. Cell targeting and ctDNA integration require ERVL, SINE or LINE DNA sequences. Chemically manufactured AluSp and MER11C sequences replicated multiple myeloma (MM) ctDNA cell targeting and integration. Additionally, we found that ctDNA may alter the treatment response of MM and pancreatic cancer models. This study shows that retrotransposon DNA sequences promote cancer gene transfer. However, because cell-free DNA has been detected in physiological and other pathological conditions, our findings have a broader impact than just cancer. Furthermore, the discovery that transposon DNA sequences mediate tissue-specific targeting will open up a new avenue for the delivery of genes and therapies.

Use of Perioperative Advanced Practice Providers to Reduce Cost and Readmission in the Postoperative Hepatopancreatobiliary Population: Results of a Simulation Study.

BACKGROUND: Postoperative healthcare use and readmissions are common among the hepatopancreatobiliary (HPB) population. We evaluated the surgical volume required to sustain advanced practice providers (APPs) in the perioperative setting for cost reduction. STUDY DESIGN: Using decision analysis modeling, we evaluated costs of employing dedicated perioperative APP navigators compared with no APPs navigators. Simulated subjects could: (1) present to an emergency department, with or without readmission, (2) present for direct readmission, (3) require additional office visits, or (4) require no additional care. We informed our model using the most current available published data and performed sensitivity analyses to evaluate thresholds under which dedicated perioperative APP navigators are beneficial. RESULTS: Subjects within the APP navigator cohort accumulated $1,270 and a readmission rate of 6.9%, compared with $2,170 and 13.5% with no APP navigators, yielding a cost savings of $905 and 48% relative reduction in readmission. Based on these estimated cost savings and national salary ranges, a perioperative APPs become financially self-sustaining with 113 to 139 annual HPB cases, equating to 2 to 3 HPB cases weekly. Sensitivity analyses revealed that perioperative APP navigators were no longer cost saving when direct readmission rates exceeded 8.9% (base case 3.7%). CONCLUSIONS: We show that readmissions are reduced by nearly 50% with an associated cost savings of $900 when employing dedicated perioperative APPs. This position becomes financially self-sufficient with an annual HPB case load of 113 to 139 cases. High-volume HPB centers could benefit from postdischarge APP navigators to optimize outcomes, minimize high-value resource use, and ultimately save costs.

Robotic versus laparoscopic gastrectomy for adenocarcinoma in the US: a propensity score-matching analysis of 11,173 patients on oncological adequacy.

INTRODUCTION: Surgery remains the cornerstone treatment for gastric cancer. Previous studies have reported better lymphadenectomy with minimally invasive approaches. There is a paucity of data comparing robotic and laparoscopic gastrectomy in the US. Herein, we examined whether oncological adequacy differs between laparoscopic and robotic approaches. METHODS: The National Cancer Database was utilized to identify patients who underwent gastrectomy for adenocarcinoma between 2010 and 2019. A propensity score-matching analysis between robotic gastrectomy (RG) versus laparoscopic gastrectomy (LG) was performed. The primary outcomes were lymphadenectomy ≥ 16 nodes and surgical margins. RESULTS: A total of 11,173 patients underwent minimally invasive surgery for gastric adenocarcinoma between 2010 and 2019. Of those 8320 underwent LG and 2853 RG. Comparing the unmatched cohorts, RG was associated with a higher rate of adequate lymphadenectomy (63.5% vs 57.1%, p < .0.0001), higher rate of negative margins (93.8% vs 91.9%, p < 0.001), lower rate of prolonged length of stay (26.0% vs 29.6%, p < .0.001), lower 90-day mortality (3.7% vs 5.0%, p < 0.0001), and a better 5-year overall survival (OS) (56% vs 54%, p = 0.03). A propensity score-matching cohort with a 1:1 ratio was created utilizing the variables associated with lymphadenectomy ≥ 16 nodes. The matched analysis revealed that the rate of adequate lymphadenectomy was significantly higher for RG compared to LG, 63.5% vs 60.4% (p = 0.01), respectively. There was no longer a significant difference between RG and LG regarding the rate of negative margins, prolonged length of stay, 90-day mortality, rate of receipt of postoperative chemotherapy, and OS. CONCLUSIONS: This propensity score-matching analysis with a large US cohort shows that RG was associated with a higher rate of adequate lymphadenectomy compared to LR. RG and LG had a similar rate of negative margins, prolonged length of stay, receipt of postoperative chemotherapy, 90-day mortality, and OS, suggesting that RG is a comparable surgical approach, if not superior to LG.

Operative Outcomes for Polycystic Liver Disease: Results of a Large Contemporary Series.

INTRODUCTION: Persistent symptoms of pain, early satiety, dyspnea, and gastrointestinal reflux due to significant liver enlargement are indications for surgical debulking in patients with polycystic liver disease (PCLD) due to the lack of effective medical therapies; however, few data exist on outcomes of surgical intervention for PCLD. METHODS: We conducted a retrospective analysis of consecutive patients who underwent operative intervention due to persistent symptoms secondary to PCLD. Preoperative patient characteristics, 30-day postoperative outcomes, and long-term postoperative outcomes, including complications and symptom resolution, were analyzed. RESULTS: We identified 50 patients who underwent hepatic resection for symptomatic PCLD. Nine patients (19%) had concomitant polycystic kidney disease, and 14 (28%) had previously undergone interventions for PCLD management. The overall complication rate was 30%, with 8 patients (16%) experiencing Clavien-Dindo Grade III-V complications and no mortalities. The median relative reduction in liver volume was 41%. At a median follow-up of 2 years, 94% has sustained symptom resolution. CONCLUSIONS: This is among the largest case series exploring PCLD operative outcomes, revealing that surgical intervention for debulking for advanced PCLD is safe and effective for symptom management. Furthermore, patients with PCLD undergoing hepatectomy tolerate significant liver volume loss without evidence of impaired hepatic function.

Gastric Cancer Surgery in the US: a Contemporary Trend Analysis of Lymphadenectomy and the Impact of Minimally Invasive Approaches.

BACKGROUND: The National Comprehensive Cancer Network guidelines recommend harvesting 16 or more lymph nodes for the adequate staging of gastric adenocarcinoma. This study examines the rate of adequate lymphadenectomy over recent years, its predictors, and its impact on overall survival(OS). STUDY DESIGN: The National Cancer Database was utilized to identify patients who underwent surgical treatment for gastric adenocarcinoma between 2006-2019. Trend analysis was performed for lymphadenectomy rates during the study period. Logistic regression, Kaplan-Meier survival plots, and Cox proportional hazard regression were utilized. RESULTS: A total of 57,039 patients who underwent surgical treatment for gastric adenocarcinoma were identified. Only 50.5% of the patients underwent a lymphadenectomy of ≥ 16 nodes. Trend analysis showed that this rate significantly improved over the years, from 35.1% in 2006 to 63.3% in 2019 (p < .0001). The main independent predictors of adequate lymphadenectomy included high-volume facility with ≥ 31 gastrectomies/year (OR: 2.71; 95%CI:2.46-2.99), surgery between 2015-2019 (OR: 1.68; 95%CI: 1.60-1.75), and preoperative chemotherapy (OR:1.49; 95%CI:1.41-1.58). Patients with adequate lymphadenectomy had better OS than patients who did not: median survival: 59 versus 43 months (Log-Rank: p < .0001). Adequate lymphadenectomy was independently associated with improved OS (HR:0.79; 95%CI:0.77-0.81). Laparoscopic and robotic gastrectomies were independently associated with adequate lymphadenectomy compared to open, OR: 1.11, 95%CI:1.05-1.18 and OR: 1.24, 95%CI:1.13-1.35, respectively. CONCLUSION: Although the rate of adequate lymphadenectomy improved over the study period, a large number of patients still lacked adequate lymph node dissection, negatively impacting their OS despite multimodality therapy. Laparoscopic and robotic surgeries were associated with a significantly higher rate of lymphadenectomy ≥ 16 nodes.

Surgical management of a giant hepatic metastasis from a cranial meningioma 10 years after resection.

Meningiomas are the most common type of primary brain tumor; they have a low risk for extracranial metastases, which are primarily associated with increased tumor grade. Hepatic metastases from cranial meningiomas are extremely rare, with only a paucity of cases reported in the literature and no standardized approach to management. Herein, we report a case of an incidentally discovered giant (>20 cm) metastatic meningioma to the liver treated with surgical resection 10 years following resection of a low-grade cranial meningioma. This report also highlights the use of (68Ga) DOTATATE PET/CT as the diagnostic imaging modality of choice when evaluating for meningioma metastases. To our knowledge, this report describes the largest hepatic metastasis from a cranial meningioma to undergo surgical resection in the literature.

Early experience with robotic central pancreatectomy with patient-reported outcomes and comparison with open central pancreatectomy.

BACKGROUND: Robotic central pancreatectomy (CP) has emerged in recent years as a noninferior approach to open CP and may offer improved patient-reported outcomes and reduction in incisional hernias. METHODS: All patients who underwent open and robotic CP between (2013 and 2022) were selected, and perioperative outcomes were analyzed. Patients who underwent robotic CP were interviewed over the phone to assess patient-reported postoperative outcomes. RESULTS: A total of 18 CP operations (56%-open vs. 44%-robotic) were identified. The overall median age was 67 years (interquartile range: 60-72), and 50% (n = 9) of patients were female. Median length of surgery was statistically longer for robotic CP (411 vs. 138 min, p = 0.002); all other intraoperative variables were similar. Postoperatively, a similar number of patients in the open and robotic cohorts developed clinically significant postoperative pancreatic fistulas (37.5% vs. 30%, p = 1) and major complications (37.5% vs. 20%, p = 0.60), respectively. No patients in the robotic cohort developed an incisional hernia, compared to 40% (n = 4) in open (p = 0.08). All patients returned to a baseline level of activity and reported a high quality of life. CONCLUSION: With the exception of longer operative times, robotic CP is a noninferior, definitive resection technique for select lesions of the middle pancreas. Additionally, the robotic approach may result in a reduction in incisional hernia development.

Does CPT Modifier 22 Appropriately Reflect a Difficult Pancreaticoduodenectomy? Retrospective Analysis of Operative Outcomes and Cost.

BACKGROUND: CPT coding allows addition of a 2-digit modifier code to denote particularly difficult procedures necessitating additional reimbursement, called the modifier 22. The use of modifier 22 in relation to pancreatic surgery and outcomes, specifically pancreaticoduodenectomy (PD), has not been explored. STUDY DESIGN: All PDs performed from 2010 to 2019 at a quaternary healthcare system were analyzed for differences in preoperative characteristics, outcomes, and cost based on the use of modifier 22. Adjusted logistic regression analysis was used to identify factors predictive of modifier 22 use. RESULTS: A total of 1,284 patients underwent PD between 2010 and 2019; 1,173 with complete data were included, of which 320 (27.3%) were coded with modifier 22. Patients coded with modifier 22 demonstrated a significantly longer duration of surgery (365.9 ± 168.4 vs 227 ± 97.1; p < 0.001). They also incurred significantly higher cost of index admission ($37,446 ± 34,187 vs $28,279 ± 27,980; p = 0.002). An adjusted multivariable analysis (specifically adjusted for surgeon variation) revealed duration of surgery (p < 0.001), neoadjuvant chemotherapy (p = 0.039), class II obesity (p = 0.019), and chronic pancreatitis (p = 0.005) to be predictive of modifier 22 use. CONCLUSIONS: Despite the subjective nature of this CPT modifier, modifier 22 is an appropriate marker of intraoperative difficulty. Preoperative and intraoperative characteristics that lead to its addition may be used to further delineate difficult PDs.

Implications of leukocytosis following distal pancreatectomy splenectomy (DPS) and association with postoperative complications.

BACKGROUND: Early identification of complications after distal pancreatectomy splenectomy (DPS) poses challenges, as white blood cell count (WBC) is confounded by physiologic leukocytosis. We examined WBC patterns associated with complications after DPS. METHODS: Clinicopathologic data were collected for patients who underwent DPS in our system from 2009 to 2016. We examined WBC, temperature, platelet count (PC), and ratios of these variables as potential early indicators of patients at risk of infections or major complications (MCs). RESULTS: 348 patients met study inclusion, of whom 206 (59%) were women and the median patient age was 59 ± 15 years. Infectious and MC rates were 11% and 16%, respectively, with <1% 30-day mortality. Postoperative WBC peaks were higher in patients with infections and MCs compared with no complication (23 vs. 17, p < 0.0001). WBC peak timing occurred postoperative day (POD) 2-3 for uncomplicated cases while peaks occurred POD9 for patients with infections and MCs. DISCUSSION: These data define patterns of leukocytosis following DPS. Although differences in infection markers were identified for patients with and without complications, no obvious thresholds were identified. Clinical suspicion for complications after DPS remains our best tool for early identification.

Narcotic sparing postoperative analgesic strategies after pancreatoduodenectomy: analysis of practice patterns for 1004 patients.

BACKGROUND: Improved post-operative outcomes have been demonstrated in gastrointestinal procedures where a narcotic sparing strategy has been utilized. Data for pancreaticoduodenectomy (PD) patients is limited. This study reviews an institutional database for outcomes based on initial analgesic strategy. METHODS: 1004 consecutive patients who underwent PD at Emory University between 2010 and 2017, were included in the analysis. Patients were divided into groups based on primary analgesic strategy employed: epidural alone (EPI), patient controlled opiate analgesia (PCA), dual (dual-PCA/EPI) and other (non-PCA/EPI). Postoperative outcomes for each group were analyzed utilizing univariate and multivariate linear regression. RESULTS: 448 (44.6%) patients were treated with EPI, 300 (29.9%) were given a PCA, 78 (7.8%) had dual-PCA/EPI and 178 (17.7%) had non-PCA/EPI analgesia. On univariate analysis, increased BMI (p = 0.030), PCA use (p < 0.001), venous thromboembolism (VTE) (p < 0.001), post-operative pancreatic fistula (POPF) (p < 0.001) and Ileus/delayed gastric emptying (DGE) (p < 0.001) were all correlated with increased LOS. On multivariate linear regression, VTE (b-coefficient 9.07, p = 0.004) POPF (8.846, p = 0.001), Ileus/DGE (4.464, p = 0.004) and PCA use (1.75, p = 0.003) were associated with significantly increased LOS. CONCLUSION: A primary narcotic sparing strategy is associated with a significantly reduced LOS and lower rates of Ileus/DGE. Mean opiate usage was significantly lower in the EPI and non-EPI/PCA groups.

The aborted Whipple: Why, and what happens next?

BACKGROUND: For patients with periampullary adenocarcinoma (PAC), pancreatoduodenectomy (PD) provides the best survival. Surgery on a subset of patients is aborted during PD. We analyzed these patients. METHODS: Patients who underwent laparotomy for planned PD for PAC were identified (2006-2019). From operative notes, we identified the subset with intraoperative decision to abort. Patient, treatment, and outcome data were analyzed. The subset with pancreatic ductal adenocarcinoma (PDAC) was analyzed for survival. RESULTS: Only 6.7% (n = 55/819) of cases were aborted. Majority 78% (n = 43) had pathologically-confirmed diagnoses at time of surgery, and 18.2% (n = 10) received preoperative chemotherapy. Reasons for aborted PD included: distant metastases (65.5%, n = 36) and local invasion (34.5%, n = 19). Of patients with metastatic disease, 75% (n = 27) had liver metastases. Eighty-nine percent (n = 49) of patients underwent at least one palliative bypass procedure and 81.8% (n = 45) had both gastric and biliary bypass. Patients with computed tomography (CT) scans before surgery more commonly had missed metastatic disease (79.2% CT compared to 54.8% magnetic resonance imaging [MRI], χ2 = 3.54, p = 0.059). In PDAC, 61.4% (n = 27/44) were aborted for metastatic disease and 38.7% (n = 17/44) for local invasion. Median overall survival for all PDAC patients after aborted PD was 334 days. CONCLUSION: Majority of pancreatoduodenectomies for periampullary adenocarcinoma are done to completion. Liver metastases is the most common reason for aborting. Preoperative MRI may help identify hepatic metastases.

Counting the cost: financial implications of complications following pancreaticoduodenectomy.

BACKGROUND: Morbidity after pancreaticoduodenectomy (PD) has been reported to be about 30-53%. These complications can double hospital costs. We sought to explore the financial implications of complications after PD in a large institutional database. METHODS: A retrospective analysis of patients undergoing PD from 2010-2017 was performed. Costs for index hospitalization were divided into categories: operating room, postoperative ward, radiology and interventional radiology. Complications were categorized according to the Clavien-Dindo classification. Univariable and mutivariable analysis were performed. RESULTS: Median cost of index admission for 997 patients who underwent PD was $23,704 (range $10,988-$528,531). Patients with major complications incurred significantly greater median costs compared to those without ($40,005 vs $21,306, p < 0.001). Patients with postoperative pancreatic fistula (POPF) grade A, B and C had progressively increasing costs ($32,164, $50,264 and $102,013, p < 0.001). On multivariable analysis ileus/delayed gastric emptying, respiratory failure, clinically significant POPF, thromboembolic complications, reoperation, duration of surgery >240 minutes and male sex were associated with significantly increased costs. CONCLUSION: Complications after PD significantly increase hospital costs. This study identifies the major contributors towards increased cost post-PD. Initiatives that focus on prevention of complications could reduce associated costs and ease financial burden on patients and healthcare organizations.

Pancreatic ductal adenocarcinomas associated with intraductal papillary mucinous neoplasms (IPMNs) versus pseudo-IPMNs: relative frequency, clinicopathologic characteristics and differential diagnosis.

The literature is highly conflicted on what percentage of pancreatic ductal adenocarcinomas (PDACs) arise in association with intraductal papillary mucinous neoplasms (IPMNs). Some studies have claimed that even small (Sendai-negative) IPMNs frequently lead to PDAC. Recently, more refined pathologic definitions for mucin-lined cysts were provided in consensus manuscripts, but so far there is no systematic analysis regarding the frequency and clinicopathologic characteristics of IPMN-mimickers, i.e., pseudo-IPMNs. In this study, as the first step in establishing frequency, we performed a systematic review of the pathologic findings in 501 consecutive ordinary PDACs, which disclosed that 10% of PDACs had associated cysts ≥1 cm. While 31 (6.2%) of these were IPMN or mucinous cystic neoplasm (MCN), 19 (3.8%) were other cyst types that mimicked IPMN (pseudo-IPMNs) per recent WHO/consensus criteria. As the second step of the study, we performed a comparative clinicopathologic analysis by also including our entire surgical pathology/consultation databases that was comprised of 60 IPMN-associated PDACs, 30 MCN-associated PDACs and 40 pseudo-IPMN-associated PDACs. We found that 84% of true IPMNs were pre-operatively recognized, whereas IPMN was considered in differential diagnosis of 33% of pseudo-IPMNs. Of the 40 pseudo-IPMNs, there were 15 secondary duct ectasias; 6 large-duct-type PDACs; 5 pseudocysts; 5 cystic tumor necrosis; 4 simple mucinous cysts; 3 groove pancreatitis-associated paraduodenal wall cysts; and 2 congenital cysts. Microscopically, pseudo-IPMNs had at least partial mucinous-lining mimicking IPMN but had smaller cystic (mean = 1.9 cm) and larger PDAC (mean = 3.8 cm) components compared to true IPMNs (cyst = 5.7 cm; PDAC = 2.0 cm). In summary, in this pathologically verified analysis that utilized refined criteria, 10% of PDACs were discovered to have cysts ≥1 cm, about two-thirds of which were IPMN/MCN but about one-third were pseudo-IPMNs. True IPMNs underlying the PDACs are often large and are already diagnosed pre-operatively as having an IPMN component, whereas only a third of the pseudo-IPMNs receive IPMN diagnosis by imaging and their cysts are smaller. At the histopathologic level, pseudo-IPMNs are highly prone to misdiagnosis as IPMN, which presumably accounts for much higher association of IPMNs with PDAC as reported in some studies. The subtle but salient characteristics of pseudo-IPMNs elucidated in this study should be combined with careful radiological/clinical correlation in order to exclude pseudo-IPMNs.

Pancreatobiliary Maljunction-associated Gallbladder Cancer Is as Common in the West, Shows Distinct Clinicopathologic Characteristics and Offers an Invaluable Model for Anatomy-induced Reflux-associated Physio-chemical Carcinogenesis.

OBJECTIVE: To determine the associations of pancreatobiliary maljunction (PBM) in the West. BACKGROUND: PBM (anomalous union of common bile duct and pancreatic duct) is mostly regarded as an Asian-only disorder, with 200X risk of gallbladder cancer (GBc), attributed to reflux of pancreatic enzymes. Methods: Radiologic images of 840 patients in the US who underwent pancreatobiliary resections were reviewed for PBM and contrasted with 171 GBC cases from Japan. RESULTS: Eight % of the US GBCs (24/300) had PBM (similar to Japan; 15/ 171, 8.8%), in addition to 1/42 bile duct carcinomas and 5/33 choledochal cysts. None of the 30 PBM cases from the US had been diagnosed as PBM in the original work-up. PBM was not found in other pancreatobiliary disorders. Clinicopathologic features of the 39 PBM-associated GBCs (US:24, Japan:15) were similar; however, comparison with non-PBM GBCs revealed that they occurred predominantly in females (F/M = 3); at younger (<50-year-old) age (21% vs 6.5% in non-PBM GBCs; P = 0.01); were uncommonly associated with gallstones (14% vs 58%; P < 0.001); had higher rate of tumor-infiltrating lymphocytes (69% vs 44%; P = 0.04); arose more often through adenoma-carcinoma sequence (31% vs 12%; P = 0.02); and had a higher proportion of nonconventional carcinomas (21% vs 7%; P = 0.03). Conclusions: PBM accounts for 8% of GBCs also in the West but is typically undiagnosed. PBM-GBCs tend to manifest in younger age and often through adenoma-carcinoma sequence, leading to unusual carcinoma types. If PBM is encountered, cholecystectomy and surveillance of bile ducts is warranted. PBM-associated GBCs offer an invaluable model for variant anatomy-induced chemical (reflux-related) carcinogenesis.

Unravelling the Complexity Myth for Minimally Invasive Right Hepatectomy: Liver Parenchymal Features and their Correlation to Objective Outcomes in Major Anatomical Resections.

BACKGROUND: Minimally invasive approaches to major liver resection have been limited by presumed difficulty of the operation. While some concerns arise from mastering the techniques, factors such as tumor size and liver parenchymal features have anecdotally been described as surrogates for operative difficulty. These factors have not been systematically studied for minimally invasive right hepatectomy (MIRH). METHODS: Seventy-five patients who underwent MIRH during 2007-2016 by the senior author were evaluated; these were compared to control group of open right hepatectomy. Demographics, operative, and post-operative variables were collected. Operative times and estimated blood loss, two objective parameters of operative difficulty were correlated to volume of hepatic resection, parenchymal transection diameter and liver parenchymal features using regression analysis. RESULTS: Thirty-eight (50.6%) resections were performed for malignant indications. Average tumor size was 5.7 cm (±3.6), mean operative time was 196 min (±74), and mean EBL was 220 mL (±170). Average transection diameter was 10.1 cm (±1.7). There was no correlation between operative difficulty with parenchymal transection diameter or presence of steatosis. Blood loss was higher with increased right hepatic lobe volume and body mass index. CONCLUSIONS: This analysis of a very defined anatomical resection suggests that the often quoted radiographic and pathologic features indicative of a challenging procedure were not significant in determining operative difficulty.