Inflammatory pseudotumors of the liver are rare and of consist of an inflammatory infiltrate that often can mimic a malignant liver neoplasm¹, without specific symptoms and specific findings in imaging and laboratory tests. We report a case of a patient with an inflammatory pseudotumor of the liver; the diagnosis was made after left liver resection.

A 42-year-old male patient sought medical advice after a previous hospitalization in other institution due to cholangitis and mild pancreatitis. He was being followed-up due to cutaneous lupus. The liver ultrasound and magnetic resonance cholangiopancreatography (MRCP) performed in the other institution showed segmental dilatation of the intrahepatic bile duct (BD) of segments IIIII with hepatolithiasis and discrete proximal focal ectasia of the BD corresponding to segment VIII, with normal extrahepatic BD. In our center, the computed tomography (CT) scan and the MRCP confirmed the findings described, also revealing a phlegmonous area in segment VIII (Fig. 1. A and B). The patient was treated with antibiotics with favorable response.

Figure 1 A: First magnetic resonance cholangiopancreatography. Axial T2-weighted sequence showing dilatation of bile ducts, periductal involvement and filling defects due to intrahepatic lithiasis (arrowhead). B: Multi-detector row CT scan with intravenous contrast agent in the initial axial plane, showing dilatation of the left lobe intrahepatic duct (arrow). The hypodense areas surrounding the duct due are due to phlegmonous changes. C: Magnetic resonance cholangiopancreatography on readmission. The axial diffusion-weighted sequence shows a restricted diffusion in the phlegmonous changes of the liver (asterisk) 

An endoscopic retrograde cholangiopancreatography (ERCP) showed focal stricture of the intrahepatic BD in the left liver lobe. The stricture was dilated and stenting was attempted but failed due to the presence of angulation. Given the difficulty in negotiating the stricture, a percutaneous transhepatic cholangiography (PTHC) was performed and demonstrated an indeterminate stricture of the left radicals in segments II-III which was dilated. A biopsy sample was obtained from a biliary stricture in segment IV; the histopathology showed a benign lesion.

A subsequent control did not demonstrate any repletion defects or strictures. The patient evolved with favorable clinical outcome and normal laboratory tests and was discharged with no signs of stricture or dilatation on control imaging tests. Ten days later he was readmitted due to cholangitis. The MRCP again showed dilatation of the left intrahepatic biliary radicals with small areas of inflammation and phlegmonous changes (Fig. 1.C). Treatment with broad-spectrum antibiotics (meropenem, vancomycin, amikacin) was initiated. Despite the clinical response was favorable and the laboratory tests results improved, the radiological findings worsened, and surgery was scheduled to rule out intrahepatic cholangiocarcinoma. The left liver had hard consistency on intraoperative palpation, and intraoperative ultrasound showed dilatation of the biliary tract in segments II-III, with central stricture and intrahepatic lithiasis. Because of these findings, left liver resection was performed without complications. The patient was discharged on postoperative day 5 but had to be readmitted 20 days later due to a fluid collection in the liver bed that was treated with antibiotics, and he was discharged 6 days later (Clavien Dindo grade I, CCI 8.7).

The histology was consistent with fibrohistiocytic inflammatory pseudotumor of the liver, with periductal growth pattern and focal nodular areas, hepatolithiasis., extensive suppurative cholangitis and sclerosing cholangitis in medium and large-sized biliary radicals. There was also focal atrophy of the parenchyma (Fig. 2). After 1-year follow-up, the patient is asymptomatic, with normal imaging tests in the right liver. The term “inflammatory pseudotumor” describes a heterogeneous group of mass-forming lesions that can involve many organs. The lesions are characterized by a prominent inflammatory infiltrate¹. Inflammatory pseudotumors of the liver account for 8% of extrapulmonary inflammatory pseudotumors². In 1953, Pack and Backer published the first case occurring in the liver. One year later, in 1954, Umiker and Iverson created the term “inflammatory pseudotumor,” as the clinical and imaging findings of the lesion mimic those of malignant tumors¹. These tumors include xanthogranuloma, fibroxanthoma, plasma cell granuloma, histiocytoma, pseudolymphoma and plasmocytoma, which reflect the histology of the components of each lesion. The etiology and pathogenesis of this disease may be related to factors such as infection, immune response, radiation, and chemotherapy^2,3. Inflammatory pseudotumor of the liver may appear after episodes of recurrent cholangitis, leading to degeneration and necrosis of the bile duct wall and periductal abscesses, biliary ectasia and development of gallstones. Other studies have mentioned the development of portal venous infection and inflammatory disease. The mass may gradually expand along with obliterative phlebitis⁴, which could explain the etiology according to the histological findings in our patient.

Figure 2 Gross examination of the surgical specimen showing abundant yellowish strands of hepatolithiasis (A) in the biliary tract with a beaded appearance and areas of stricture and dilatation. The wall of the bile duct is circumferentially thickened, with firm consistency and periductal tumor appearance, with areas of white branches that follow the branching pattern of the bile tree and occasional masses as white nodules with a size of 0.3-1 cm in the periphery of the specimen (B). 

Symptoms are atypical and include abdominal pain, fever and weight loss³ as in our patient, who presented only fever and exhaustion. Liver function and tumor markers are usually normal or slightly elevated³. The lesion can reach a size > 20 cm and imaging tests findings are unspecific, possibly due to the amount of fibrosis and cellular infiltration⁵. The mass usually appears as hypondense or isodense on CT scan, and magnetic resonance imaging (MRI) shows hyperintense or isointense T1 signal and T2 hyperintensity or isointensity. The correct diagnosis cannot be made without histopathological examination as these tumors can be easily misdiagnosed as other liver neoplasms³. Percutaneous biopsy of inflammatory pseudotumors of the liver has low efficacy and is not free of complications. Although liver biopsy indisputably plays a role in the work-up and management of liver metastases of unknown origin, its role is more contentious and possibly dangerous in cases of a solitary hepatic mass that is likely to be malignant. The main histopathological findings are the presence of myofibroblastic spindle cells, plasma cells, macrophages, and lymphocytes without cellular atypia or atypical mitotic figures⁵.

There is no standard of care (gold standard) or a method to determine the outcome of inflammatory pseudotumor of the liver². Treatment is controversial and some authors suggest that surgery is the definitive treatment for patients with serious symptoms or an indeterminate diagnosis. Other authors consider corticosteroids as the standard therapy⁶. Several multicenter studies have shown good results after conservative treatment with antibiotics, corticosteroids, or both, but recurrences may occur. However, it is reasonable to resect the tumor in the absence of a definitive diagnosis. This approach is preferred because it minimizes the risk of biopsyrelated complications, such as dissemination in cases of malignancy, avoids the possibility of recurrence of inflammatory pseudotumor of the liver, and provides histology with a definitive diagnosis^1,2. In the case of our patient, the tests performed did not rule out the presence of cholangiocarcinoma, and we decided to perform liver resection without biopsy due to the risk of malignancy. Another possible diagnosis to consider in patients with recurrent cholangitis and segmental dilatation of the biliary tract is Caroli’s disease affecting one lobe which, as in our patient, manifests with recurrent cholangitis and can be associated with hepatolithiasis. Single-lobe disease can be solved by liver resection⁷.

In the absence of typical features of malignancy in the diagnostic tests of a liver mass, alternative diagnoses of rare liver lesions as inflammatory pseudotumor of the liver should be considered. Conservative treatment can be indicated if the diagnosis of inflammatory pseudotumor of the liver is confirmed. However, surgical resection remains the treatment of choice for patients with serious symptoms or an indeterminate diagnosis.