Akinari Fukuda

Severe congenital protein C (PC) deficiency is a rare inherited coagulation disorder that can be difficult to control with conventional medical treatment alone. We report a single‐center case series of three pediatric patients with severe congenital PC deficiency who underwent liver transplantation (LT). In all patients, plasma PC activity levels exceeded 64% after LT and remained stable without anticoagulation treatment or PC supplementation. Two patients were followed for more than 10 years, representing the longest reported outcomes to date. Stable anticoagulant function persisted despite rejection, graft dysfunction, and subsequent surgery, demonstrating durable restoration of physiological anticoagulant function after LT.

Background: Intussusception of the Roux‐en‐Y limb after pediatric liver transplantation (LT) is an extremely rare but potentially life‐threatening complication. Altered anatomy, postoperative adhesions, and disrupted intestinal motility create a unique pathophysiological environment, which may delay diagnosis and increase morbidity. Methods: We retrospectively analyzed a patient with acute intestinal obstruction after living donor liver transplantation. Clinical presentation, laboratory findings, imaging results, intraoperative observations, surgical management, and outcomes were reviewed. The potential pathogenesis was explored in relation to factors such as Roux‐en‐Y reconstruction, graft‐to‐recipient size ratio, and postoperative adhesive disease. Results: The patient presented with fever and melena. Laboratory evaluation revealed leukocytosis and severe anemia. Computed tomography demonstrated small bowel intussusception with obstruction. Emergency laparotomy identified intussusception of the proximal Roux limb near the biliary‐enteric anastomosis. Manual reduction was unsuccessful, necessitating segmental resection without reconstruction of a new Roux limb. Extensive intra‐abdominal adhesions were noted. Postoperative recovery was uneventful, and graft function remained stable. Conclusions: Intussusception of the Roux‐en‐Y limb following pediatric living donor liver transplantation is a complex surgical emergency. This case demonstrates that in the transplant population, symptoms such as fever and melena should trigger immediate cross‐sectional imaging to rule out mechanical obstruction. The management strategy must be aggressive yet conservative regarding anatomical disruption. As the population of long‐term pediatric transplant survivors grows, recognizing these distinct mechanistic patterns is essential for reducing morbidity and mortality.

Background: Aeromonas species can cause bacteremia, but their epidemiology and clinical significance in pediatric liver transplant (LT) recipients are unclear. We evaluated the incidence, clinical features, management, and outcomes of Aeromonas bacteremia in this population. Methods: We performed a retrospective observational study at a tertiary pediatric LT center from November 2005 to April 2023. Patients who underwent LT before 18 years of age were reviewed, and cases of Aeromonas bacteremia were analyzed in detail. Results: Among 746 children who underwent LT, five episodes of Aeromonas bacteremia were identified. The incidence was 0.82 cases per 1000 person‐years. Median age at LT was 2 years, and median interval from LT to bacteremia was 6 years (range, 2 months–24 years). All patients were receiving maintenance immunosuppression without neutropenia or significant liver dysfunction, and none were receiving antibiotics, including trimethoprim–sulfamethoxazole prophylaxis at the time of Aeromonas bacteremia. No patient had recent hepatobiliary procedures or biliary obstruction. All presented with fever; three had fever without source, and three reported freshwater exposure. Blood cultures yielded A. hydrophila / caviae ( n = 3) or A. sobria (currently A. veronii biovar sobria) ( n = 2). All isolates were susceptible to the empiric antibiotic regimens. Definitive therapy consisted of cefotaxime or cefepime, with or without metronidazole. All patients survived without progression to life‐threatening sepsis or relapse. Conclusions: In pediatric LT recipients, Aeromonas bacteremia can occur late after transplantation under mild immunosuppression and without recognizable biliary risk factors. Early recognition and appropriate antibiotic therapy may contribute to favorable outcomes.

Background: Pediatric liver retransplantation (ReLT) remains technically complex and is associated with increased postoperative complications and mortality. However, pediatric‐specific data including surgical challenges are limited. This retrospective single‐center study evaluated long‐term outcomes, complications, and surgical considerations of pediatric ReLT. Methods: In this retrospective single‐center study, we analyzed 25 pediatric patients (< 18 years) who underwent ReLT between 2005 and 2025. Clinical characteristics, perioperative variables, postoperative complications, and survival outcomes were assessed. Patient and graft survival were estimated using Kaplan–Meier analysis, and prognostic factors for mortality were examined using univariate logistic regression. Results: Among 908 primary liver transplant recipients, 25 patients (2.7%) underwent ReLT. The mean age at ReLT was 5.5 years, with a mean interval of 3.0 years from primary transplantation. Major indications included refractory rejection ( n = 14, 56.0%) and chronic rejection ( n = 7, 28.0%), and early ReLT (< 1 year) was performed in 17 patients (68.0%). Patient survival at 1, 3, and 5 years was 83.6%, 79.5%, and 79.5%, respectively, with corresponding graft survival of 78.7%. Kaplan–Meier analysis showed no statistically significant difference in patient or graft survival according to donor type or timing of ReLT. Although complex vascular reconstruction was frequently required, no early vascular complications occurred. Early postoperative complications developed in 13 patients (52.0%). Graft failure was the only factor significantly associated with mortality. Conclusions: In conclusion, liver retransplantation in pediatric recipients remains a complex but feasible treatment option with acceptable outcomes. However, given the small sample size and single‐center nature of this study, further multicenter investigations are required to better define prognostic factors and optimize management strategies.

Background.: Valganciclovir (VGCV) is the first-line therapeutic agent for cytomegalovirus (CMV) infection following pediatric liver transplantation (LT). The dosage for pediatric patients is either determined by body weight (BW dose) or body surface area (BSA) and renal function (7 × BSA [m ² ] × creatinine clearance (CrCl) [mL/min/1.73 m ² ]) (BSA dose). However, the optimal dosing strategy for achieving target drug exposure for CMV treatment remains unclear. Methods.: We conducted a prospective pharmacokinetic study in pediatric LT patients. The area under the concentration-time curve (AUC _0–24 ) was estimated using previously reported pediatric population pharmacokinetic parameters. An AUC _0–24 of 80–120 µg·h/mL was defined as the therapeutic target. The primary endpoint was to compare the achievement rate of target AUC between BW and BSA doses. Although BW dose is the standard at our institution, a hypothetical BSA dose was estimated proportionally for comparison with BW dose. Results.: Fourteen patients with a median age of 1.1 y were included. The median VGCV dose was 15.3 mg/kg, whereas the hypothetical median BSA dose was 24.5 mg/kg. The estimated AUC _0–24 in BW and BSA dose groups were as follows: 120 µg·h/mL, 0.0% and 21.4% ( P = 0.027). There was a negative correlation between AUC _0–24 and the duration of CMV viremia, indicating that higher AUC values were associated with faster viral clearance (ρ = −0.72, P = 0.003). Conclusions.: Based on our estimation, BSA dosing may be more likely to achieve the target AUC _0–24 compared with BW dosing in infant/toddler LT recipients. Higher AUC values correlated with faster viral clearance.

Background: Cryptogenic liver cirrhosis in infancy is rare, and its coexistence with hepatoblastoma (HB) has not been previously documented. While HB generally arises in morphologically normal livers, the incidental discovery of HB within cirrhotic livers is exceptional. Case Presentation: We report a 6‐month‐old male infant with progressive cholestasis. Prenatal assessments indicated growth restriction and blood flow redistribution, and he was delivered preterm at 33 weeks and 6 days with a birth weight of 861 g (−4.1 SD). Despite extensive clinical, metabolic, infectious, and genetic evaluations, no etiology of cholestasis was identified. Liver function was deteriorated with a Child‐Pugh score of 8 (Grade B) and a Pediatric End‐Stage Liver Disease Score of 20. The patient underwent living donor liver transplantation at 6 months of age (body weight: 4.446 kg). Histopathological examination of the explanted liver revealed advanced fibrosis, and unexpectedly, a microscopic hepatoblastoma (approximately 1 mm, fetal type) was detected. The high level of serum AFP rapidly normalized postoperatively, and the infant was discharged in good condition. Discussion: This case highlights a unique presentation of infantile cryptogenic cirrhosis with incidental HB. Although HB typically develops in non‐cirrhotic livers, hepatic injury and regenerative processes may create a permissive environment for tumorigenesis of HB in cirrhotic liver. The incidental finding of one millimeter HB emphasizes the importance of thorough histopathological evaluation of explanted livers. Moreover, careful postoperative surveillance with AFP monitoring and imaging remains essential to detect recurrence, as localized HB after complete resection carries a reported recurrence risk of approximately 6%. Conclusion: This is the first reported case of incidental HB arising in infantile cryptogenic cirrhosis. It expands the clinical spectrum of HB in infantile cryptogenic cirrhosis.

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Background: Portal vein (PV) reconstruction is a crucial step in pediatric liver transplantation (LT). Pediatric recipients with a hypoplastic or sclerotic PV often require an interposition vein graft. Allogeneic grafts from donors are generally preferred. However, if they are not available, the use of autologous vessels is necessary. Case Presentation: An 8‐month‐old girl with biliary atresia (BA) underwent living donor LT with a left lateral segment graft. During the operation, portal vein thrombosis (PVT) developed after direct anastomosis between the recipient PV and graft left PV. We used several techniques to resolve this problem, including ligation of collateral circulation and use of interposition grafts from the left internal jugular vein (IJV) and left renal vein (LRV). On postoperative day 1, PVT reoccurred. Emergency exploratory laparotomy was performed for thrombectomy, using the retrohepatic inferior vena cava (IVC) as an additional vascular graft. The final reconstruction successfully utilized a combination of LRV and IVC grafts between the superior mesenteric vein and graft left PV. Postoperatively, the patient received thrombolytic therapy followed by anticoagulants for thrombus prevention, along with immunosuppressive drugs. The patient's postoperative clinical course was uneventful. Conclusion: Although the IJV and LRV are established options for PV reconstruction in pediatric LT, we propose retrohepatic IVC as a feasible and effective alternative option. This approach maximizes the availability of autologous vessels; however, selection must be individualized based on graft availability and the patient condition.