Extrahepatic biliary atresia with choledochal cyst: Prenatal MRI predicted and post natally confirmed: A case report
A 25-year-old primigravida presented to our hospital at 22nd week of gestation for target scan Targetted imaging for fetal anomalies (TIFFA). Fetal biometric parameters were normal. Liquor was adequate. Anatomical survey revealed a longitudinally oval, avascular anechoic cyst measuring 14 × 9 mm in the right upper abdomen, separate from duodenum, showing continuity with hepatic hilum superiorly without identifiable gall bladder (GB). No other abnormalities were detected. Presumptive diagnosis of CDC was made.\nFetal MRI was performed 2 weeks later on 1.5T Essenza (Siemens, Erlangen, Germany) to investigate the correct anatomical location of the cyst and its relationship with adjacent organs to assist with prognostication and treatment planning for the perinatal period.\nT2-weighted Half-Fourier acquisition single-shot turbo spin-echo (HASTE, TR/TE 900/86 ms, 4-mm slice thickness) sequences were obtained in the axial, coronal, and sagittal planes with respect to the fetus. Sequences were monitored in real time and manipulated to determine optimal imaging planes during the scan, as fetal orientation is unpredictable and often changes during acquisitions. In addition to the standard orthogonal planes, oblique planes were acquired for demonstrating the relationship to surrounding structures.\nMRI showed a 14 × 9 mm ellipsoid [] homogenous cystic lesion at liver hilum hyperintense on T2W images. Axial images revealed the cyst posterior to the duodenum []. The cyst was longitudinally oval, coursing posteroinferiorly from hepatic hilum appreciated on sagittal images []. Intrahepatic ducts were not dilated; CBD was not visualized. Coronal images revealed hyperintense cord-like structure above the cyst, showing communication with it []. The normal morphology of fetal GB was not visualized in the inferior surface of liver in right upper quadrant. The spleen was normal. Inferior vena cava (IVC) showed normal course. Liver showed normal signal intensity and contour.\nThe imaging characteristics on USG and MRI are presented in .\nFollow-up using serial USG scans in pregnancy revealed static size of the cyst with persistent ghost GB. Interval growth was normal till term.\nA female infant weighing 2.9 kg was delivered by cesarean section at 39 weeks.\nPostnatal USG, on day 3 after a 4-h fast, revealed liver extending beyond subcostal margin; echotexture was homogenous with normal surface contour. Intrahepatic ducts were not dilated. There was an echogenic area anterior to the portal vein at porta and measured 3.2 mm []. A well-defined, longitudinally oval anechoic cyst was present at the hilum ~14 × 9 mm. The cyst size, echogenicity, and morphology were the same as seen in prenatal imaging []. Maximum width and length of GB was 11 × 2 mm, with irregular, compressed lumen s/o ghost GB []. Hepatic artery was prominent, running parallel to the right portal vein, and measured 1.7 mm. Main portal vein (MPV) diameter was obtained at the same level, which measured 3 mm. The ratio of HA/MPV diameter was >0.5 (>0.45 increase) []. Hepatic subcapsular flow appeared subjectively increased. Spleen measured 3.8 cm. No varices were present. No free fluid was noted.\nThe imaging characteristics at porta are presented in .\nLiver function tests (LFT) revealed increased γ-glutamyl transferase (831 U/L), elevated alkaline phosphatase (698 U/L), conjugated hyperbilirubinemia (2.8 mg/dL), and normal serum glutamate pyruvate transaminase (SGPT) 10 U/L, serum glutamate oxaloacetate transaminase (SGOT) 29 U/L, albumin, and International Normalised Ratio [(INR). Hepatobiliary scintigraphy was performed on day 24 which showed prompt and good uptake by the liver and absent tracer excretion into the intestines in 24-h delayed images. GB and extrahepatic ducts were not visualized [].\nA diagnosis of extrahepatic cystic biliary atresia (CBA) was made based on imaging.\nThe child was explored with on day 31. Operative findings included firm brownish liver, fibrotic porta inclusive of non-visualized right/left hepatic duct, common hepatic duct, and proximal CBD []. GB was small and did not have a lumen. A cystic structure was seen at the site of terminal part of CBD. The cyst was going behind the duodenum and ending blindly. No communication was seen with the pancreatic duct. Corresponding schematic representation is shown in and was classified as type 3 BA according to Japanese classification system.\nExcision of fibrotic hilar structures including cyst en masse with a Kasai's portoenterostomy was performed with ~30 cm of Roux-en-Y jejunal loop. Histopathologic examination confirmed the diagnosis of BA. Bilirubin returned to 1 mg by the 11th postoperative day. The child is aged 2 months now and doing well.