A biloma is a rare disease characterized by an abnormal intra- or extrahepatic bile collection due to a traumatic or spontaneous rupture of the biliary system. Laboratory findings are nonspecific. The diagnosis is usually suspected on the basis of a typical history (right upper quadrant abdominal pain, chills, fever and recent abdominal trauma or surgery) and is confirmed by detection of typical radiologic features. We report the case of a patient with a history of previous cholecystectomy for lithiasis who presented with clinical symptoms and laboratory data suggestive of acute pancreatitis. Imaging studies also revealed the presence of a chronic and asymptomatic biloma, which could be mistaken for a pseudocyst. The atypical location and ultrasound findings suggested an alternative diagnosis. We therefore reviewed the known literature for bilomas, focusing on the role of ultrasonography, which can reveal some typical aspects, such as location and imaging features. We conclude that ultrasound plays a key role in the assessment of a suspected biloma in patients with appropriate history and clinical features and provides valuable diagnostic clues even in the absence of these.

A biloma is a rare disease characterized by an abnormal intra- or extrahepatic bile collection secondary to a traumatic or spontaneous rupture of the biliary system. Post-traumatic cases were first reported by Whipple[1], who described the case of a patient kicked by a horse, but the term “biloma” was coined by Gould et al[2], who described a subject with extrahepatic bile leakage in the upper right quadrant of the abdomen after trauma from fighting. In the past, the common bile duct damage after open cholecystectomy was rated about 0.1%. Nowadays, with the laparoscopic technique, rates range from 0.3%-0.6%[3]. In a retrospective study that identified 18 patients with one or more documented intra-abdominal bilomas, the most frequent causes were iatrogenic (n = 16), in particular after cholecystectomy, partial hepatectomy and bile-duct catheter drainage; only two were post-traumatic[4]. After laparoscopic cholecystectomy, most of the lesions occur within 7 d[5]. The majority of minor bilomas resolve spontaneously without further complications[6]. Occasionally, spontaneous rupture of the biliary duct is reported, sometimes associated with choledocholithiasis. Other possible causes are cholangiocarcinomas, acute cholecystitis, tuberculosis, hepatic abscesses or infarctions. Rarely, an association with pancreatic cancer is described[7,8]. Biloma can complicate sickle cell disease[9,10]. The clinical features consist primarily of pain or abdominal distension, malaise, anorexia, nausea, chills and fever. If associated with choledocholithiasis, the bilomas may occur with jaundice, dark urine and acholic stools. Less frequently they are asymptomatic. Usually the lesions are diagnosed in an average time of 1-2 wk[11].

Laboratory exams may document the presence of neutrophilic leucocytosis and increased values of erythrocyte sedimentation rate and C-reactive protein (CRP), and these may suggest a concomitant cholangitis[7]. Occasionally, abnormal values ​​of aspartate aminotransferase and alanine aminotransferase may be detected[12]. In the presence of jaundice, laboratory tests may show signs of cholestasis (elevation of serum alkaline phosphatase, total and direct bilirubin) as the result of biliary obstruction by gallstones or, less frequently, of extrahepatic biliary ductal compression caused by the biloma[13,14].

The diagnosis is suspected on the basis of the clinical history (e.g., recent cholecystectomy or abdominal trauma), location of the lesion, ultrasound and computed tomography (CT) appearance and can be confirmed by magnetic resonance (MR) cholangiopancreatography and by the features of the material obtained by ultrasonography-guided percutaneous aspiration. The bilomas must be differentiated from other similar findings, such as lymphocele, abscesses, hematomas, pseudocysts, liver cysts and seroma[4]. Gallbladder scintigraphy with technetium-99 may help to differentiate the biloma from hematomas or liver abscesses. Endoscopic retrograde cholangiography may provide not only further diagnostic confirmation but also a therapeutic option, allowing decompression of the bile duct and biliary drainage of the collection[15-19]. In the case of recurrence or persistence of the biloma, more invasive treatment strategies may be considered. In one study, surgical treatment was found to be associated with a higher complication rate[17]. If the collection is well confined or if there are small residual gallstones, surgical access by subcostal laparotomy is appropriate[20,21]. In case of bile leakage arising after hepatectomy, percutaneous transhepatic biliary drainage is the treatment of choice[21]. Kyoden et al[22] evaluated the use of prophylactic abdominal drainage performed in 1269 consecutive cases of elective liver resection in order to reduce the frequency of the development of subphrenic fluid collections and bile leakage. Placement of drains was effective in a significant number of patients undergoing hepatectomy.

A 72-year-old woman was admitted to our Hospital for the persistence, from the day before, of acute and stabbing epigastric pain, not associated with nausea, vomiting, diarrhea or fever. The patient did not report unusual food intake or recent travel. She reported a history of ischemic heart disease, previous multiple pulmonary infarctions treated with oral anticoagulants, type 2 diabetes mellitus in good metabolic control, Hashimoto’s thyroiditis and a past history of cholecystectomy for lithiasis (12 years before). The physical examination revealed the presence of evoked pain by deep palpation in the epigastrium and torpid peristalsis. The remaining examination was normal. Laboratory tests documented fasting hyperglycemia (> 200 mg/dL), hyperamylasemia (3420 U/L), increased values of lipase (24667 U/L), CRP (8.3 mg/dL) and leukocytosis (14000/mL) with neutrophilia. Hemoglobin, serum electrolytes, indices of cholestasis, liver enzymes and cardiac markers were normal. An electrocardiogram, performed in the emergency room, showed signs of previous myocardial infarction. Abdominal X-ray showed poor distension of the bowel loops in the absence of other findings. An ultrasound examination of the upper abdomen revealed, in the IV hepatic segment and in proximity of the site of previous cholecystectomy, the presence of a heterogeneous hypo-anechoic rounded lesion, with a maximum size of 3.89 cm × 3.42 cm and hyperechoic, calcified walls; it was equipped with numerous hyperechoic debris generating acoustic shadow (Figure 1A). The lesion did not demonstrate an increase in color Doppler signal (Figure 1B). The pancreas showed a normal size with heterogeneous echotexture and blurred margins. The clinical, laboratory and pancreatic ultrasound findings were suggestive for acute pancreatitis. These data were confirmed by a contrast-enhanced abdominal CT, which showed inflammation of the pancreatic tissue and peritoneal effusion. The focal lesion localized in the IV hepatic segment had a hypodense appearance and did not enhance after intravenous administration of contrast agent (Figure 2). It was bounded by a wall thickening of a few mm and showed a thin septum in its lateral portion. The lesion’s appearance was not specific and was not supported by the clinical and laboratory findings, which strongly indicated a diagnosis of acute pancreatitis.

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Figure 1 Chronic biloma in a 72-year-old woman: ultrasound findings. A: Oblique view shows a heterogeneous hypo-anechoic rounded lesion with hyperechoic, calcified walls (arrows), numerous hyperechoic debris generating acustic shadow (arrow heads) and maximum size of 3.89 cm (caliper 1) × 3.42 cm (caliper 2); B: Color Doppler sonogram shows absence of vascularity inside the lesion (arrows). pv: Portal vein; ivc: Inferior vena cava.

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Figure 2 Computed tomography shows the biloma as a hypodense lesion in the IV hepatic segment, characterized by absence of enhancement after administration of intravenous contrast agent (arrow). RL: Right hepatic lobe; LL: Left hepatic lobe; IV: Fourth hepatic segment; k: Kidney; ivc: Inferior vena cava; ao: Aorta; sc: Spinal column.

With the establishment of fasting and appropriate supportive care, the patient became asymptomatic again with optimal values of pancreatic function. However, the hepatic lesion persisted despite adequate treatment and was not due to simple pseudocyst, because of the atypical location and appearance. At magnetic resonance imaging (MRI) the lesion appeared intense on T₁-weighted images and hyperintense on T₂-weighted images (Figure 3A). In addition, because of its location in proximity of the site of the previous cholecystectomy, a contrast-enhanced MR cholangiopancreatography was performed, which revealed a close proximity between the lesion and the stump of the remnant cystic duct. The lesion seemed to arise posteriorly to the confluence of the right and left hepatic ducts into the common hepatic duct (Figure 3B).

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Figure 3 Biloma features on magnetic resonance imaging. A: On T₂-weighted images, the biloma appeared as a hyperintense lesion located in the IV hepatic segment (arrow); B: Contrast enhanced magnetic resonance cholangiopancreatography shows the biloma as a well-defined, rounded lesion (arrow) arising posteriorly to the confluence of right and left hepatic ducts into the common hepatic duct (arrowhead) in proximity to the stump of the remnant cystic duct (star). RL: Right hepatic lobe; LL: Left hepatic lobe; IV: Fourth hepatic segment; ivc: Inferior vena cava; ao: Aorta; pv: Portal vein; sc: Spinal column; sp: Spleen; chd: Common hepatic duct; cbd: Common bile duct.

Biloma was diagnosed. Considering the surgical risk of the patient and the fact that the lesion was found many years after cholecystectomy, the surgeon did not advise intervention. The patient is undergoing follow-up with ultrasonography every 6 mo to confirm the stability of the lesion over time.