Efficacy and safety of shunt surgery in patients with idiopathic normal-pressure hydrocephalus: can we predict shunt response by preoperative magnetic resonance imaging (MRI)?

AIM: The aim of this study was to identify preoperative magnetic resonance imaging (MRI) findings that can predict the shunt responsiveness in idiopathic normal-pressure hydrocephalus (iNPH) patients and to investigate postoperative outcome and complications. MATERIALS AND METHODS: A total of 192 patients with iNPH who underwent shunt at our hospital between 2000 and 2021 were included to investigate complications. Of these, after exclusion, 127 (1-month postoperative follow-up) and 77 (1-year postoperative follow-up) patients were evaluated. The preoperative MRI features (the presence of tightness of the high-convexity subarachnoid space, Sylvian fissure enlargement, Evans' index, and callosal angle) of the shunt-response and nonresponse groups were compared, and a systematic review was conducted to evaluate whether preoperative MRI findings could predict shunt response. RESULTS: Postoperative complications within one month after surgery were observed in 6.8% (13/192), and the most common complication was hemorrhage. Changes in corpus callosum were observed in 4.2% (8/192). The shunt-response rates were 83.5% (106/127) in the 1-month follow-up group and 70.1% (54/77) in 1-year follow-up group. In the logistic regression analysis, only Evans' index measuring >0.4 had a significant negative relationship with shunt response at 1-month follow-up; however, no significant relationship was observed at 1-year follow-up. According to our systematic review, it is still controversial whether preoperative MRI findings could predict shunt response. CONCLUSION: Evans' index measure of >0.4 had a significant relationship with the shunt response in the 1-month follow-up group. In systematic reviews, there is ongoing debate about whether preoperative MRI findings can accurately predict responses to shunt surgery. Postoperative corpus callosal change was observed in 4.2% of iNPH patients.

Direct thermal injury to the popliteal artery after total knee arthroplasty.

Vascular damage after total knee arthroplasty is rare. However, delayed diagnosis and management may cause adverse outcomes for patients. In particular, direct thermal injury to the popliteal artery after total knee arthroplasty is extremely rare. A 74-year-old woman presented to another institution with a left popliteal artery injury after left total knee arthroplasty. Arteriography revealed total occlusion of the popliteal artery, and emergency surgery was performed. Because of the total occlusion of the popliteal artery due to severe direct thermal injury, anastomosis was performed in an end-to-end fashion with a right great saphenous vein graft. At the time of discharge, she had no specific symptoms other than pain at the surgical site, with a palpable left dorsalis pedis pulse. While performing total knee arthroplasty, the anatomical position of the popliteal artery should be carefully considered to prevent injury.

Imaging findings of primary hepatic angiosarcoma on gadoxetate disodium-enhanced liver MRI: comparison with hepatic haemangiomas of similar size.

AIM: To describe imaging characteristics of primary hepatic angiosarcoma on gadoxetate disodium-enhanced dynamic magnetic resonance imaging (MRI) and to determine features that differentiate angiosarcomas from similar-sized haemangiomas. MATERIALS AND METHODS: The study included 15 patients with hepatic angiosarcomas and 35 patients with size-matched hepatic haemangiomas who underwent gadoxetate disodium-enhanced liver MRI. The number, size, growth pattern, signal intensity (SI) characteristics, and SI changes on dynamic scans were evaluated and compared between the two entities. RESULTS: Overall, hepatic angiosarcomas significantly more often showed lesion multiplicity (86.7%), capsular retraction (40%), prominent intratumoural vessels (66.7%), vascular invasion (20%), heterogeneous SI on T2-weighted (100%) and hepatobiliary phase images (80%), and intralesional haemorrhage (60%, all p<0.05). On dynamic scans, angiosarcomas demonstrated enhancing foci of irregular or rim-like nodular/linear or bizarre (86.7%) shapes, with centrifugal or bizarre patterns of progressive enhancement (53.3%). Enhancement of angiosarcomas was less than that of the blood pool on visual grading, but the enhancement curves followed that of the aorta. Regardless of size, angiosarcomas showed heterogeneous T2 SI, intratumoural haemorrhage, and heterogeneity during the hepatobiliary phase, whereas these findings were more common in haemangiomas >6 cm in diameter. CONCLUSION: Gadoxetate disodium-enhanced dynamic liver MRI is capable of depicting vascular hallmarks of hepatic angiosarcomas. Heterogeneous SI on T2-weighted and hepatobiliary phase images, multiplicity, and an enhancement curve following that of the aorta are also distinctive features that differentiate angiosarcomas from haemangiomas.

Use of vertebral body units to locate the cavoatrial junction for optimum central venous catheter tip positioning.

BACKGROUND: Central venous catheter (CVC) placement plays an important role in clinical practice; however, optimal positioning of the CVC tip remains a controversial issue. The objective of this study was to evaluate the use of vertebral body unit (VBUs), to locate the cavoatrial junction (CAJ), for optimal CVC tip placement based on chest radiography (CXR) using the carina as a landmark. METHODS: 524 patients who underwent coronary computed tomographic angiography (CTA) and CXR were included. The position of the CAJ was identified using VBUs, and the efficacy of VBUs for locating the CAJ with the carina as a landmark was analysed using multiple regression analysis. A VBU was defined as the distance between two adjacent vertebral bodies, including the inter-vertebral disk space. RESULTS: The mean (sd) distance from the carina to the superior CAJ was 54.3 (9.7) mm on CTA; the mean distance in VBUs at the level of the carina was 21.4 (1.7) mm on CTA and 22.6 (2.1) mm on CXR. The mean CAJ position was 2.5 VBUs below the carina on CTA and 2.4 VBUs below on CXR with 95% limits of agreement between -0.6 and +0.3. CONCLUSIONS: The position of the CVC tip in relation to the carina can be described using the thoracic spine as an internal ruler, and the position of the CAJ in adults was reliably estimated to be 2.4 VBUs below the carina. CLINICAL TRIAL REGISTRATION: KCT0001319.

Development of a multi-channel visible bremsstrahlung measurement system for the effective charge in the versatile experiment spherical torus (VEST).

A diagnostic system for measuring the effective charge in the versatile experiment spherical torus (VEST) has been developed. The system utilizes a toroidal array to observe the plasma radius on the low magnetic field side, providing a spatially resolved Zeff. The target wavelength of visible bremsstrahlung (VB) was carefully selected to avoid contamination by line emissions. The detector signal was calibrated using a halogen light source and an integrating sphere to obtain an absolute value of the radiative power from each chord. The local emissivity profile was reconstructed from the line-integrated VB emission using the Abel inversion method. Reconstruction tests were performed on various shapes of phantom profiles to effectively reconstruct the local emissivity from the measurements. We found that the initial measurements of the multi-channel VB system were consistent with the results of other independent measurements, supporting the validity of the new measurements. Finally, we obtained the initial result of Zeff in the VEST.

Phase II study of a trastuzumab biosimilar in combination with paclitaxel for HER2-positive recurrent or metastatic urothelial carcinoma: KCSG GU18-18.

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) is a widely explored therapeutic target in solid tumors. We evaluated the efficacy and safety of trastuzumab-pkrb, a biosimilar of trastuzumab, in combination with paclitaxel, in HER2-positive recurrent or metastatic urothelial carcinoma (UC). PATIENTS AND METHODS: We enrolled 27 patients; they were administered a loading dose of 8 mg/kg trastuzumab-pkrb on day 1, followed by 6 mg/kg and 175 mg/m2 paclitaxel on day 1 every 3 weeks, intravenously. All patients received six cycles of the combination treatment and continued to receive trastuzumab-pkrb maintenance until disease progression, unacceptable toxicity, or for up to 2 years. HER2 positivity (based on immunohistochemistry analysis) was determined according to the 2013 American Society of Clinical Oncology /College of American Pathologists HER2 testing guidelines. The primary endpoint was objective response rate (ORR); the secondary endpoints were overall survival (OS), progression-free survival (PFS), and safety. RESULTS: Twenty-six patients were evaluated via primary endpoint analysis. The ORR was 48.1% (1 complete and 12 partial responses) and the duration of response was 6.9 months [95% confidence interval (CI) 4.4-9.3 months]. With a median follow-up of 10.5 months, the median PFS and OS were 8.4 months (95% CI 6.2-8.8 months) and 13.5 months (95% CI 9.8 months-not reached), respectively. The most common treatment-related adverse event (TRAE) of any grade was peripheral neuropathy (88.9%). The most common grade 3/4 TRAEs were neutropenia (25.9%), thrombocytopenia (7.4%), and anemia (7.4%). CONCLUSIONS: Trastuzumab-pkrb plus paclitaxel demonstrates promising efficacy with manageable toxicity profiles in patients with HER2-positive recurrent or metastatic UC.

Characterization of liver metastases: the efficacy of biphasic magnetic resonance imaging with ferucarbotran-enhancement.

AIM: To retrospectively evaluate the efficacy of biphasic magnetic resonance imaging (MRI) of the liver with ferucarbotran-enhancement for the characterization of hepatic metastases. MATERIALS AND METHODS: Thirty-six patients underwent MRI of the liver with separate acquisition of double-contrast enhancement consisting of gadolinium and ferucarbotran. A total of 106 focal hepatic lesions (51 metastases, 31 cysts, 23 haemangiomas, and one eosinophilic abscess) were included. Two sets of MRI were analysed: (1) ferucarbotran set: ferucarbotran-enhanced T1-weighted (T1W) dynamic imaging combined with ferucarbotran-enhanced T2*-weighted (T2*W) delayed imaging and (2) double set: gadolinium-enhanced T1W dynamic imaging combined with ferucarbotran-enhanced T2*W delayed imaging. The diagnostic accuracy of the two sets was evaluated using alternative free-response receiver operating characteristic curve analysis. Sensitivity and specificity were compared using the McNemar test. The enhancement pattern of focal hepatic lesions was analysed on gadolinium and ferucarbotran-enhanced T1W dynamic imaging. RESULTS: There was no significant difference in the accuracy of characterizing hepatic metastases between the two sets. Sensitivity and specificity were not significantly different between the sets (p>0.05). Peripheral rim enhancement was exhibited in 57% of metastatic lesions on ferucarbotran-enhanced T1W dynamic imaging. The majority (96%) of hepatic haemangiomas demonstrated typical peripheral nodular enhancement with progression on ferucarbotran-enhanced T1W dynamic imaging and were easily differentiated from metastases. CONCLUSION: Biphasic MRI of the liver with ferucarbotran-enhancement alone provided comparable diagnostic efficacy to double-contrast MRI for the characterization of hepatic metastases.

Rupture of carotid artery pseudoaneurysm in the modern era of definitive chemoradiation for head and neck cancer: Two case reports.

BACKGROUND: Carotid blowout syndrome (CBS) is a rupture of the carotid artery and is mainly caused by radiation and resection of head and neck cancers or direct tumor invasion of the carotid artery wall. It is a life-threatening clinical situation. There is no established and effective mode of management of CBS. Furthermore, there is no established preceding sign or symptom; therefore, preventive efforts are not clinically meaningful. CASE SUMMARY: We described two cases of CBS that occurred in patients with head and neck cancer after definitive chemoradiotherapy (CRT) using three-dimensional conformal intensity-modulated radiation therapy. Two men aged 61 and 56 years with locally advanced head and neck cancer were treated with definitive CRT. After completing CRT, both of them achieved complete remission. Subsequently, they had persistent severe pain in the oropharyngeal mucosal region and the irradiated neck despite the use of opioid analgesics and rehabilitation for relief of contracted skin. However, continuous follow-up imaging studies showed no evidence of cancer recurrence. Eleven to twelve months after completing CRT, the patients visited the emergency room complaining about massive oronasal bleeding. Angiograms showed rupture of carotid artery pseudoaneurysms on the irradiated side. Despite attempting to secure hemostasis with carotid arterial stent insertion and coil embolization, both patients died because of repeated bleeding from the pseudoaneurysms. CONCLUSION: In patients with persistent pain in irradiated sites, clinicians should be suspicious of progressing or impending CBS, even in the three-dimensional conformal intensity-modulated radiation therapy era.

Isolated perihepatic tuberculosis: imaging findings.

AIM: To review the imaging findings of isolated perihepatic tuberculosis without coexistent active tuberculosis elsewhere in the body. MATERIALS AND METHODS: Over a 9-year period, six patients with histopathologically proven perihepatic tuberculosis without simultaneous active tuberculosis elsewhere in the body were included in this study. Two radiologists retrospectively evaluated in consensus the location (right, left, or both perihepatic spaces), size (maximum diameter), morphology (ovoid or round), number, attenuation (low-, iso-, or high-attenuation compared with the adjacent liver parenchyma), and the presence or absence of contrast enhancement of the lesions on computed tomography (CT), and echogenicity (low-, iso-, or high-echogenicity compared with the adjacent liver parenchyma) of the lesions on ultrasonography. RESULTS: On CT, an isolated perihepatic lesion was located in the right perihepatic space in five patients, whereas three lesions were located in both perihepatic spaces in the remaining patient. The mean maximum diameter of the isolated perihepatic tuberculosis lesions was 29.7 mm. Isolated perihepatic tuberculosis appeared as an ovoid-shaped, homogeneous, and low-attenuating (n=5) or high-attenuating (n=1) lesion relative to the liver. There was peripheral rim enhancement of the lesion in two patients. On ultrasonography, isolated perihepatic tuberculosis was revealed as a homogeneous, low-echoic (n=5) or iso-echoic (n=1) lesion relative to the liver. CONCLUSION: Although various inflammatory or malignant lesions can be located in the perihepatic space, isolated perihepatic tuberculosis appears an ovoid-shaped, homogeneous, and low-attenuating or low-echoic lesion compared with the liver parenchyma on CT or ultrasonography.

Co-expression of nerve growth factor and p75NGFR in the inferior alveolar nerve after mandibular distraction osteogenesis.

During mandibular distraction osteogenesis (DO), the inferior alveolar nerve (IAN) is damaged during distractor activation, but spontaneously recovers during consolidation. Although many neurotrophic factors are known to play critical roles, there have been few studies on the mechanism of peripheral nerve recovery after DO. The aim of this study was to observe the expression pattern of p75NGFR (low-affinity receptor of NGF) and to detect autocrine growth activity in IANs following mandibular DO. Unilateral mandibular distractions (0.5mm each, twice per day for 10 days) were conducted on eight mongrel dogs. Two each were killed at 7, 14, 28 and 56 days after completing distraction. The distracted IAN and contralateral control nerve were harvested. Immunohistochemical staining was performed to determine p75NGFR expression, and double immunofluorescent staining to detect NGF and p75NGFR co-expression. Levels of p75NGFR expression were found to be significantly elevated at 7 and 14 days in Schwann cells located in the outer layer of axon, but were almost undetectable at 28 and 56 days. In double immunofluorescent images, the co-expression of NGF and p75NGFR was also detected at 7 and 14 days. p75NGFR plays an important role in remyelination due to its abundant expression in Schwann cells of damaged nerves, and NGF is an autocrine growth factor present in distracted IANs during the early consolidation period after mandibular DO.

Expression of vascular endothelial growth factor and its receptors after mandibular distraction osteogenesis.

During distraction osteogenesis, angiogenic activity is essential for new bone formation. This study examined the expression of vascular endothelial growth factor (VEGF) and two of its receptors, Flt-1 (VEGFR-1) and Flk-1 (VEGFR-2), in cellular components after mandibular distraction osteogenesis. Unilateral mandibular distraction (0.5 mm twice per day for 10 days) was performed in six mongrel dogs. Two animals each were killed on days 7, 14 and 28 after completion of distraction. The distracted mandibular segments and contralateral undistracted control segments were harvested and processed for immunohistochemical examination. Seven days after distraction, there was a significant increase in the expression levels of VEGF and its receptors in the osteoblasts, osteocytes and immature fibroblast-like cells compared to control specimens. These levels were maintained for 14 days after distraction in the osteoblasts and fibroblast-like cells. Twenty-eight days after distraction, VEGF and VEGFR-1 were expressed only moderately/weakly in the osteoblasts, and no VEGFR-2 expression was detected in the cellular component of the distracted bone. Throughout the observation period, VEGFR-1 expression was stronger than that of VEGFR-2. The expression patterns of VEGF and its receptors suggest that it plays an important role in osteogenesis, and that osteoblasts and immature fibroblast-like cells of the distracted bone may have an autocrine growth effect during distraction osteogenesis.

Status analysis and strategic framework for sanitation management in Asia and Africa.

Following rapid population increase and industrial development, the ever increasing environmental pollution and the associated sanitation-related problem are no longer regional or local but have become an issue requiring global-dimensional concern and the provision of problem-solving alternatives. Especially, since most problems result from inappropriate sewerage and the lack of sewage treatment system are in a serious state occurring in economically underdeveloped regions, and as such, their significance is enormous. The United Nations Environment Programme (UNEP) has been making efforts to establish the technology selection methodology applicable in developing countries, through the accurate status, investigation and analysis of the wastewater management state in Asian and African regions, and the sanitation management guideline utilisable by political leaders or decision-makers. As part of this effort, the Korea Institute of Water Environment (KIWE), together with the UNEP, selected China and Vietnam (in Asia) and Kenya and Ethiopia (in Africa) as subject countries to investigate and perform on-site sanitation management investigations and analysis in this research. Results obtained from the on-site investigation were analysed, and in order to be helpful in establishing a strategy for sanitation management in underdeveloped countries, the strategic framework (SF) has been made based on characterised results.

Expression of nerve growth factor and vascular endothelial growth factor in the inferior alveolar nerve after distraction osteogenesis.

The objective of this study was to evaluate changes occurring in the inferior alveolar nerve (IAN) subsequent to mandibular distraction osteogenesis, with regard to the expression of nerve growth factor (NGF) and vascular endothelial growth factor (VEGF). Unilateral mandibular distractions (0.5mm each, twice per day for 10 days) were conducted on 8 mongrel dogs. Two animals were killed at 7, 14, 28 and 56 days after completion of distraction. The distracted IAN and contralateral control nerve were then harvested and analysed histologically and immunohistochemically. Signs of acute nerve injury, including demyelination, were observed in the distracted IAN on the 7th and 14th day after distraction. At 56 days, the histological features of the distracted IAN were similar to those of the control nerve. The levels of NGF and VEGF expression were significantly elevated on the 7th and 14th day after distraction. NGF was expressed in most of the distracted nerve tissues, but VEGF was primarily detected in Schwann cells and the neurovasorum. VEGF expression had returned to normal but NGF expression was still profoundly elevated 28 days after distraction. NGF expression returned to normal levels at 56 days after distraction. NGF and VEGF appeared to have been elicited from the Schwann cells and damaged nervous tissues, and they may play important roles in the initial healing of damaged nerves. VEGF expression returned to normal more quickly than did NGF expression. This may indicate that hypoxic conditions within the distracted nerve had recovered to normal during the early stages of consolidation. Micro-vessels in the distracted nerve may have recovered more rapidly than did the nerve tissue itself.

The effect of gadoxetic acid enhancement on lesion detection and characterisation using T2 weighted imaging and diffusion weighted imaging of the liver.

OBJECTIVES: To evaluate the effect of gadoxetic acid enhancement on the detection and characterisation of focal hepatic lesions on T(2) weighted and diffusion weighted (DW) images. METHODS: A total of 63 consecutive patients underwent T(2) weighted and DW imaging before and after gadoxetic acid enhancement. Two blinded readers independently identified all of the focal lesions using a five-point confidence scale and characterised each lesion using a three-point scale: 1, non-solid; 2, indeterminate; and 3, solid. For both T(2) weighted and DW imaging, the accuracies for detecting focal lesions were compared using the free-response receiver operating characteristic analysis; the accuracies for lesion characterisation were compared using the McNemar test between non-enhanced and gadoxetic acid-enhanced image sets. For hepatic lesions ≥ 1 cm, the lesion-to-liver contrast-to-noise ratio (CNR) and the apparent diffusion coefficient (ADC) were compared in the non-enhanced and enhanced image sets using the generalised estimating equations. RESULTS: For both T(2) weighted and DW images, the accuracies for detecting focal lesions (p ≥ 0.52) and those for lesion characterisation (p ≥ 0.63) did not differ significantly between the non-enhanced and enhanced image sets. The lesion-to-liver CNR was significantly higher on enhanced DW images than on non-enhanced DW images (p=0.02), although the difference was not significant for T(2) weighted imaging (p=0.65). The mean ADC values of lesions did not differ significantly on enhanced and non-enhanced DW imaging (p=0.75). CONCLUSION: The acquisition of T(2) weighted and DW images after administration of gadoxetic acid has no significant effect on the detection or characterisation of focal hepatic lesions, although it improves the lesion-to-liver CNR on DW images.

Metastatic acinar cell carcinoma of the liver from a benign-appearing pancreatic lesion: a mimic of hepatocellular carcinoma.

Acinar cell carcinoma (ACC) is a rare pancreatic tumour with a favourable prognosis compared with the more common ductal adenocarcinoma. The radiological findings of this tumour have been described in the literature; however, only limited data are available regarding the metastatic features of ACC of the liver, the most common metastatic site. We report a case of ACC of the pancreas with a hepatic metastasis from a benign-appearing malignant pancreatic lesion.

Pancreatic ductal adenocarcinoma with intratumoral cystic lesions on MRI: correlation with histopathological findings.

The purpose of this study was to evaluate intratumoral cystic lesions of pancreatic ductal adenocarcinoma (PDAC) depicted on MRI, and to correlate these cystic lesions with their histopathological findings. This study included 12 patients (7 males and 5 females; mean age, 59 years) with intratumoral cystic lesions of PDAC detected on a retrospective MRI review. We reviewed the histopathological findings of the cystic lesions within PDACs and analysed the MRI findings, focusing on the appearance of the intratumoral cystic lesions, i.e. the size, number, margin and intratumoral location, and on the ancillary findings of PDAC, i.e. peripancreatic infiltration, upstream pancreatic duct dilatation and distal parenchymal atrophy. Intratumoral cystic lesions were classified as neoplastic mucin cysts (n = 7, 58%) or cystic necrosis (n = 5, 42%) according to the histopathological findings; they ranged in greatest dimension from 0.5 cm to 3.4 cm (mean, 1.7 cm). Seven patients had only one cystic lesion each, while the remaining five had multiple cystic lesions. Most of the neoplastic mucin cysts had smooth margins (n = 6, 86%) and eccentric locations (n = 6), whereas most cystic necroses had irregular margins (n = 4, 80%) and centric locations (n = 4). The most common ancillary findings of PDAC were peripancreatic infiltration, distal pancreatic atrophy and upstream pancreatic duct dilatation (92%, 75% and 58%, respectively). The intratumoral cystic lesions of PDACs on MRI were classified as either neoplastic mucin cysts with smooth margins and eccentric locations or cystic necroses with irregular margins and centric locations.

Gastric schwannomas: radiological features with endoscopic and pathological correlation.

AIM: To describe the radiological, endoscopic, and pathological findings of gastric schwannomas in 16 patients. MATERIALS AND METHODS: The radiological, endoscopic, and pathological findings of 16 surgically proven cases of gastric schwannoma were retrospectively reviewed. All patients underwent computed tomography (CT) and four patients were evaluated with upper gastrointestinal series. Two radiologists reviewed the CT and upper gastrointestinal series images by consensus with regard to tumour size, contour, margin, and growth pattern, the presence or absence of ulcer, cystic change, and the CT enhancement pattern. Endoscopy was performed in eight of these 16 patients. Six patients underwent endoscopic ultrasonography. Pathological specimens were obtained from and reviewed in all 16 patients. Immunohistochemistry was performed for c-kit, CD34, smooth muscle actin, and S-100 protein. RESULTS: On radiographic examination, gastric schwannomas appeared as submucosal tumours with the CT features of well-demarcated, homogeneous, and uncommonly ulcerated masses. Endoscopy with endoscopic ultrasonography demonstrated homogeneous, submucosal masses contiguous with the muscularis propria in all six examined cases. On pathological examination, gastric schwannomas appeared as well-circumscribed and homogeneous tumours in the muscularis propria and consisted microscopically of interlacing bundles of spindle cells. Strong positivity for S-100 protein was demonstrated in all 16 cases on immunohistochemistry. CONCLUSION: Gastric schwannomas appear as submucosal tumours of the stomach and have well-demarcated and homogeneous features on CT, endoscopic ultrasonography, and gross pathology. Immunohistochemistry consistently reveals positivity for S-100 protein in the tumours.

Duplication of the extrahepatic bile duct with anomalous union of the pancreaticobiliary ductal system revealed by MR cholangiopancreatography.

MR cholangiopancreatography (MRCP) is a valuable, non-invasive tool for accurate examination of the biliary system. We report a case in which MRCP played a critical role in the diagnosis of a duplication of the extrahepatic bile duct with anomalous union of the pancreaticobiliary ductal system in a patient with hilar cholangiocarcinoma. This variant of a duplication of the extrahepatic biliary system has not been described previously in the literature.