Beyond cholangiocarcinoma: imaging features of mimicking pathologies in the biliary tract

Cholangiocarcinoma (CCA) is the second most common primary malignancy of the hepatobiliary system and presents as a heterogeneous disease with three distinct morphological subtypes: mass-forming, periductal-infiltrating, and intraductal-growing, each characterized by distinguishing imaging features. Accurate diagnosis of CCA is challenging due to the overlap of imaging findings with a broad range of benign and malignant conditions. Therefore, it is essential for radiologists to recognize these mimickers and offer a reasonable differential diagnosis, as this has a significant impact on patient management. Although histopathological confirmation is often required for a definitive diagnosis, understanding specific imaging characteristics that differentiate CCA from its mimickers is crucial. This article highlights a variety of benign and malignant conditions that resemble CCA on imaging, emphasizing features that enhance diagnostic accuracy in clinical practice.

Case report on serohepatic tuberculosis (frosted liver): Clinical presentation, imaging, diagnosis, and management

Hepatic tuberculosis can manifest in various forms, including parenchymal, serohepatic, tuberculous cholangitis and mixed form. Isolated hepatic tuberculosis, specifically in the form of serohepatic tuberculosis, is very rare. Patients with hepatic tuberculosis often present with nonspecific symptoms such as abdominal pain, weight loss, night fever, night sweats, hepatomegaly, and abnormal liver function tests. This case involves a young male with isolated serohepatic tuberculosis who presented to the outpatient department of a tertiary care center with complaints of abdominal discomfort, weight loss, and evening rise in temperature. His liver function tests showed elevated levels of alanine transaminase and aspartate aminotransferase. Ultrasonography of the abdomen revealed multiple subcapsular necrotic lesions in the right lobe of the liver. A contrast-enhanced computed tomography scan of the abdomen showed a few hypodense subcapsular lesions in the right lobe and a minimal subcapsular collection. There was mild thickening and enhancement of the liver capsule and sub capsule, creating a frosted liver or sugar-coated appearance. A small subcentimetric size parenchymal lesion was present in segment VIII, which was in continuity with the subcapsular collection. Fine needle aspiration cytology from the largest subcapsular liver lesion revealed acid-fast bacillus, confirming the tuberculosis diagnosis. A high-resolution CT scan of the chest was performed for further evaluation and showed no abnormalities. The patient is currently being treated with antitubercular therapy.

Benign and malignant focal liver lesions displaying rim arterial phase hyperenhancement on CT and MRI

Rim arterial phase hyperenhancement is an imaging feature commonly encountered on contrast-enhanced CT and MRI in focal liver lesions. Rim arterial phase hyperenhancement is a subtype of arterial phase hyperenhancement mainly present at the periphery of lesions on the arterial phase. It is caused by a relative arterialization of the periphery compared with the center of the lesion and needs to be differentiated from other patterns of peripheral enhancement, including the peripheral discontinuous nodular enhancement and the corona enhancement. Rim arterial phase hyperenhancement may be a typical or an atypical imaging presentation of many benign and malignant focal liver lesions, challenging the radiologists during imaging interpretation. Benign focal liver lesions that may show rim arterial phase hyperenhancement may have a vascular, infectious, or inflammatory origin. Malignant focal liver lesions displaying rim arterial phase hyperenhancement may have a vascular, hepatocellular, biliary, lymphoid, or secondary origin. The differences in imaging characteristics on contrast-enhanced CT may be subtle, and a multiparametric approach on MRI may be helpful to narrow the list of differentials. This article aims to review the broad spectrum of focal liver lesions that may show rim arterial phase hyperenhancement, using an approach based on the benign and malignant nature of lesions and their histologic origin. CRITICAL RELEVANCE STATEMENT: Rim arterial phase hyperenhancement may be an imaging feature encountered in benign and malignant focal liver lesions and the diagnostic algorithm approach provided in this educational review may guide toward the final diagnosis. KEY POINTS: Several focal liver lesions may demonstrate rim arterial phase hyperenhancement. Rim arterial phase hyperenhancement may occur in vascular, inflammatory, and neoplastic lesions. Rim arterial phase hyperenhancement may challenge radiologists during image interpretation.

Comments and Illustrations of Ultrasound Findings in Extrapulmonary Tuberculosis Manifestations

This review describes the appearance of extrapulmonary tuberculosis manifestations in comprehensive and multiparametric ultrasound imaging. The aim is to increase awareness of typical ultrasound findings regarding extrapulmonary tuberculosis, correlate those with pathological features, and facilitate differential diagnosis. Point of care ultrasound protocols can be used as a screening method in high-risk populations, although the negative findings do not exclude tuberculosis. Conversely, the diagnosis of extrapulmonary tuberculosis can never be made using ultrasound alone, as many ultrasound findings in extrapulmonary tuberculosis are non-specific. However, ultrasound-based sampling techniques can significantly facilitate the collection of samples for microbiological or molecular proof of tuberculosis, as well as facilitating the establishment of alternative diagnoses.

Hepatobiliary tuberculosis in the developing world

BACKGROUND

Hepatobiliary tuberculosis is a challenging disease that poses diagnostic difficulties due to its resemblance to other etiologies. Delayed diagnosis may lead to inadequate treatment, thus necessitating an urgent need for accurate diagnosis and appropriate management.

AIM

To systematically review case reports on hepatobiliary tuberculosis, focusing on symptomatology, diagnostic procedures, management, and outcomes to provide patient safety and ensure an uneventful recovery.

METHODS

A systematic search was conducted on PubMed from 1992 to 2022, using keywords such as hepatobiliary, liver, tuberculosis cholangitis, cholangiopathy, and mycobacterium. Only case reports or case series in English were included in the study, and research papers published as abstracts were excluded. The search yielded a total of 132 cases, which were further narrowed down to 17 case studies, consisting of 24 cases of hepatobiliary tuberculosis.

RESULTS

The 10 most common symptoms observed in these cases were fever, abdominal pain, weight loss, jaundice, anorexia, generalized weakness, pruritus, chills, fatigue, and chest pains. Objective findings in these cases included hepatomegaly, hepatic nodules, elevated liver enzymes, and elevated bilirubin. Computed tomography scan and ultrasound of the abdomen were the most useful diagnostic tools reported. Histologic demonstration of Mycobacterium tuberculosis confirmed the cases of hepatobiliary tuberculosis. Treatment regimens commonly used included Rifampicin, Isoniazid, Pyrazinamide, and Ethambutol. Out of the 24 cases, 18 presented improvements while 4 had completely recovered.

CONCLUSION

Hepatobiliary tuberculosis is a disease that requires accurate diagnosis and appropriate management to avoid complications.

Imaging recommendations and algorithms for pediatric tuberculosis: part 2-extrathoracic tuberculosis

Despite advances in diagnosis and treatment in recent years, tuberculosis (TB) remains a global health concern. Children are amongst the most vulnerable groups affected by this disease. Although TB primarily involves the lungs and mediastinal lymph nodes, it can affect virtually any organ system of the body. Along with clinical history combined with physical examination and laboratory tests, various medical imaging tools help establish the diagnosis. Medical imaging tests are also helpful for follow-up during therapy, to assess complications and exclude other underlying pathologies. This article aims to discuss the utility, strengths and limitations of medical imaging tools in the evaluation of suspected extrathoracic TB in the pediatric population. Imaging recommendations for the diagnosis will be presented along with practical and evidence-based imaging algorithms to serve as a guide for both radiologists and clinicians.

Abdominal visceral tuberculosis: a malignancy mimic

The purpose is to discuss abdominal tuberculosis mimicking malignancy involving the abdominal viscera. TB of the abdominal viscera is common, especially in countries where tuberculosis is endemic and in pockets of non-endemic countries. Diagnosis is challenging as clinical presentations are often non-specific. Tissue sampling may be necessary for definitive diagnosis. Awareness of the early and late disease imaging appearances of abdominal tuberculosis involving the viscera that can mimic malignancy can aid detecting TB, providing a differential diagnosis, assessing extent of spread, guiding biopsy, and evaluating response.

Liver Mass Caused by Mycobacterium fortuitum: A Rare Case Diagnosed by EUS-FNA

Mycobacterium fortuitum is associated with skin and soft-tissue infections, yet isolated liver involvement is rare. A 67-year-old asymptomatic man was referred for endoscopic ultrasound (EUS) to evaluate a gastric lesion and an incidental liver mass. EUS revealed a heterogeneous liver mass that was sampled. Pathology revealed necrotic granulomatous inflammation and positive acid-fast bacilli stain with M. fortuitum deoxyribonucleic acid. Levofloxacin plus trimethoprim and sulfamethoxazole for 3 months were used for complete resolution of liver lesion. Isolated nontuberculous liver involvement is uncommon. We report the first case of a liver mass caused by M. fortuitum diagnosed by EUS-fine needle aspiration.

Misdiagnosis of Hepatosplenic Schistosomiasis as Hepatic Tuberculosis: A Case Report

We report a case of a 38-year-old woman who was initially misdiagnosed with hepatic tuberculosis and was managed as such before being correctly diagnosed with hepatosplenic schistosomiasis on liver biopsy. The patient had a five-year history of jaundice which over time was accompanied by polyarthritis and then abdominal pain. A diagnosis of hepatic tuberculosis was made clinically and supported by radiographic evidence. She underwent an open cholecystectomy for gallbladder hydrops with the liver biopsy taken revealing chronic hepatic schistosomiasis and was eventually started on praziquantel with good recovery. This case demonstrates a diagnostic issue with the radiographic presentation of the patient and the important role of tissue biopsy in providing definitive care.

Extrapulmonary tuberculosıs: an old but resurgent problem

Tuberculosis (TB) primarily affects the lungs, but some of its most devastating clinical consequences arise because of its ability to spread from the lungs to other organs. Extrapulmonary TB (EPTB) constitutes 15-20% of all TB cases. Imaging findings are not always specific and can mimic many diseases; therefore, EPTB should be considered in the differential diagnosis, particularly in patients with immune system disorders (AIDS, patients receiving chemotherapy, etc.) and those in other high-risk groups including people with diabetes. The bacterium's passage to the regional lymph nodes is essential for developing a protective T-cell-mediated immune response, but the bacterium can spread hematologically and via the lymphatic system, leading to extrapulmonary involvement. Diagnosis of EPTB in high-risk patients is made based on suspected clinical and radiological findings, but further positive culture and histopathological confirmation may be required in some instances. Radiological evaluations are critical for diagnosis and crucial in planning the treatment and follow-up. This paper aims to review the typical and atypical imaging features and the differential diagnosis of EPTB.

Hepatic tuberculosis masquerading as malignancy

BACKGROUND AND AIMS

Hepatic tuberculosis (HTB) is rare and mimics neoplastic liver lesions clinico-radiologically leading to misdiagnosis and even unnecessary surgery.

METHODS AND MATERIAL

We analysed 43 cases of HTB diagnosed at a referral cancer centre over 10 years. Clinical details, investigations and treatment received were noted.

RESULTS

The median age was 46 years with a female preponderance (58%). HTB was diagnosed incidentally in 28% cases during surveillance imaging for a previous cancer. Constitutional symptoms (31, 72%), abdominal pain (25, 58%), fever (12, 28%), hepatomegaly (22, 51%), elevated alkaline phosphatase (34, 79%), elevated aminotransferases (18, 42%) and hypoalbuminemia (19, 45%) were common features. All cases had negative HIV serology and normal tumor markers. Twenty-two (52.5%) had solitary liver lesion and lesions > 2 cm in 28 (65%). Ultrasound showed hypoechoic lesions in 31 of 33 cases. Computed tomography showed hypodense lesions (43,100%) with mild peripheral enhancement (32, 74%). Calcifications (5, 12%) and capsular retraction (8, 19%) was uncommon. MRI was performed in seven cases commonly showed T1 hypointense, T2 hyperintense lesions with restricted diffusion. Histopathology showed granulomatous inflammation (42, 97.5%), Langhan's giant cells (41, 95%) and caseation necrosis (35, 85%). Acid-fast stain and PCR positivity was uncommon. Extrahepatic organs were involved in 20 (46.5%). HTB mimicked cholangiocarcinoma (25, 58%), liver metastasis (11, 26%) and lymphoma (3, 7%). Six patients underwent liver resection with a presumptive diagnosis of cancer without a preoperative biopsy. All patients received antitubercular therapy, 37 had clinico-radiological response, there were 3 deaths and 3 patients were lost to follow-up.

CONCLUSION

HTB is rare and can mimic a malignancy clinico-radiologically. Calcifications and pseudocapsule appearance on multiphase CT scan may help in differentiating HTB from hepatic malignancy. Tumor markers are normal while histopathology is generally diagnostic. A high index of suspicion is required to avoid unnecessary surgery as the patients respond well to ATT.

TRIAL REGISTRATION

This is a retrospective and observational study hence clinical trial registration is not applicable.

Focal hepatic intrinsically hyperattenuating lesions at unenhanced CT: Not always calcifications

Due to the growing use of CT, there has been an increase in the frequency of detecting focal liver lesions. Intrinsically hyperattenuating hepatic lesions or pseudolesions are not uncommon at unenhanced CT. Hyperattenuating hepatic lesions can be divided into non-calcified and calcified. Causes of intrinsic hyperattenuation include hemorrhage, thrombosis, and calcifications. Focal liver lesions can show hyperattenuation on unenhanced CT in case of severe liver steatosis. Recognition of etiologies associated with hyperattenuation on unenhanced CT can help the radiologist in characterizing focal liver lesions and pseudolesions. In this paper, we describe the spectrum of intrinsically hyperattenuating focal liver lesions and pseudolesions at unenhanced CT.

Contrast-Enhanced Ultrasound LI-RADS LR-5 in Hepatic Tuberculosis: Case Report and Literature Review of Imaging Features

Background: The liver is involved in disseminated tuberculosis in more than 80% of cases while primary liver involvement is rare, representing <1% of all cases. Hepatic tuberculosis (TB) can be treated by conventional anti-TB therapy; however, diagnosing this disease remains a challenge. The diagnosis might be particularly difficult in patients with a single liver lesion that could be misdiagnosed as a tumor or other focal liver lesions. Although computed tomography (CT) and magnetic resonance imaging (MRI) findings have been described, there is a paucity of literature on contrast-enhanced ultrasound (CEUS) features of hepatic TB. Case Summary: herein, we describe a case of a patient with tuberculous lymphadenopathy and chronic Hepatitis C Virus (HCV)-related liver disease who developed a single macronodular hepatic TB lesion. Due to the finding of a hepatocellular carcinoma (HCC) highly suggestive CEUS pattern, specifically a LR5 category according to the Liver Imaging Reporting and Data System (LI-RADS), and a good response to antitubercular therapy, a non-invasive diagnosis of HCC was made, and the patient underwent liver resection. We also review the published literature on imaging features of hepatic TB and discuss the diagnostic challenge represented by hepatic TB when occurs as a single focal liver lesion. Conclusions: this report shows for the first time that the CEUS pattern of hepatic TB might be misinterpreted as HCC and specific imaging features are lacking. Personal history and epidemiological data are mandatory in interpreting CEUS findings of a focal liver lesion even when the imaging pattern is highly suggestive of HCC.

Gallbladder Tuberculosis Presenting as Obstructive Jaundice

Isolated gallbladder tuberculosis is a rare entity, even in endemic zones. Preoperative diagnosis is usually not possible, with most of the cases being diagnosed either as cholecystitis or malignancy. Histopathological examination of the resected specimen clinches the diagnosis. We present a middle-aged man with obstructive jaundice who was diagnosed to have gallbladder malignancy clinically and radiologically and on microscopy, and was diagnosed as gallbladder tuberculosis with the involvement of the common bile duct.

Hot liver on 18F-FDG PET/CT imaging—a quandary for oncoradiologists in South Asia

A 56-year-old female presented with intermittent hemoptysis and was diagnosed with lung cancer. 18F-fluorodeoxyglucose positron emission tomography/CT for staging revealed hypermetabolic liver (hot liver), uptake in the mediastinal lymph nodes and reduced uptake in the kidneys. Unexpectedly, liver biopsy findings were consistent with tuberculous infection. Following the intensive phase of antituberculous treatment, repeat CT revealed significant resolution of the mediastinal lymph nodes making the lung cancer Stage 1 (T1 lesion). She underwent left lower lobectomy as a definitive surgical treatment. Positron emissiontomography/CT scan in this patient was considered to be a hepatic superscan since it revealed a hot liver.

Non-neoplastic hepatopancreatobiliary lesions simulating malignancy: can we differentiate?

Despite the success of cross-sectional imaging in evaluating hepatopancreatobiliary system malignancies, several non-malignant disease processes may closely mimic malignancy. Differentiating these benign diseases from malignancy may be difficult, or even impossible, even in the hands of experienced imagers. In this manuscript, we present benign mimics involving the hepatopancreatobiliary system and try to increase awareness of these potential pitfalls.

Abdominal Tuberculosis Mimicking Cancer Clinically and on Fluorodeoxyglucose (FDG)-Positron Emission Tomography (PET) Imaging: A Two-Case Series

Case series

Patients: Male, 76-year-old • Male, 53-year-old

Final Diagnosis: Disseminate tuberculosis and liver tuberculoma

Symptoms: Fatigue

Medication: —

Clinical Procedure: —

Specialty: Surgery

Biopsy-diagnosed renal granuloma after intravesical bacillus Calmette-Guérin therapy for bladder carcinoma: a case series and review of the literature

Renal granuloma is a rare complication affecting the kidneys after intravesical bacillus Calmette-Guérin (BCG) therapy for bladder carcinoma. Our case series review describes the imaging and histopathological findings of BCG-induced renal granulomas. All three renal granulomas, which were located in the upper pole, had a solitary mass-like appearance. The mean diameter was 31.3 mm. In the two cases, the lesion was homogeneously enhanced on post-contrast CT, and presented homogeneous low signal intensity on T₂ weighted imaging (T₂WI) and iso-signal intensity on diffusion-weighted imaging (DWI). Both lesions had increased fludeoxyglucose (FDG) uptake. Histological examinations revealed granulomatous inflammation with fibrosis. The third case showed a lesion having heterogeneous enhancement on CT, heterogeneous and slightly high signal intensity on T₂WI, and high signal intensity on DWI. This case showed more severe inflammatory cell infiltration and less fibrosis than the former two cases did. It was suggested that the signal intensity on T₂WI and DWI depends on the degree of inflammation and fibrosis in renal granuloma. It is currently challenging to distinguish renal granuloma from renal malignancy based on only imaging findings. Biopsies were helpful in confirming the diagnosis and avoiding unnecessary resection. Renal granuloma should be considered as a differential diagnosis when a renal mass is found in a patient with a history of intravesical BCG treatment.

A Retrospective Case-Control Study to Evaluate the Diagnostic Accuracy of Honeycomb Sign in Melioid Liver Abscess

Among pyogenic liver abscesses, melioid etiology is considered in endemic regions in the presence of known health or occupational risk factors. "Honeycomb sign," used to describe an abscess with multiple internal septations dividing the abscess cavity into multiple loculations of comparable sizes on imaging, is a sensitive sign for melioid liver abscess. This is a retrospective case-control study investigating incidence, sensitivity, and specificity of "honeycomb sign" in melioid liver abscess, in a cohort of patients with culture-proven melioidosis infection. Abscesses ≥ 2 cm were analyzed for the honeycomb sign. P value < 0.05 was taken as statistically significant. Interobserver agreement was calculated between two radiologists for the presence of the sign, sensitivity, and specificity. A total of 40 abscesses were analyzed. Thirty-four abscesses (85%) manifested the honeycomb sign with interobserver agreement (kappa = 0.70 and 0.92). Sensitivity of the sign is 85% (95% confidence interval [CI]: 70-94%), specificity is 75% (95% CI: 59-87%), positive predictive value is 77% (95% CI: 62-88%), and negative predictive value is 83% (95% CI: 67-94%). If abscess size is ≥ 3 cm, the sensitivity is 91% (95% CI: 77-98%), specificity is 75% (95% CI: 59-87%), positive predictive value is 76% (95% CI: 61-88%), and negative predictive value is 91% (95% CI: 76-98%). Honeycomb sign is a novel imaging marker for melioid liver abscess. Increased awareness and recognition of this imaging feature has the potential to affect patient management.

Common and uncommon imaging features of abdominal tuberculosis

Despite the advances in the medical care, tuberculosis (TB) still remains an important health problem. This is particularly relevant to the developing countries as well as the immunocompromised population in the developed world. Multidrug resistance poses another challenge and may be responsible for increasing incidence of TB, to some extent. The respiratory system is the most commonly involved, although any organ system may be affected. Abdominal involvement occurs in 11-12% of the patients with extrapulmonary TB. The clinical features of abdominal TB are nonspecific. Imaging plays an important role in the diagnosis of abdominal TB. Although a few imaging features strongly favour the possibility of TB, abdominal TB is a greater masquerader. In this review, we highlight the entire spectrum of the manifestations of abdominal tuberculosis (excluding the genitourinary involvement) with an emphasis on imaging findings.

Computed tomographic features of abdominal tuberculosis: unmask the impersonator!

PURPOSE

Abdominal tuberculosis (ATB) mimics various infectious, inflammatory, and neoplastic conditions and hence requires a high index of suspicion for accurate diagnosis, especially in low prevalence areas. It is difficult to consistently establish a histopathological diagnosis of ATB which underlines the importance of supportive evidences for institution of prompt empirical therapy to prevent associated morbidity and mortality.

METHODS

We retrospectively evaluated clinical and imaging features of 105 ATB cases and classified their CT findings based on peritoneal, lymph node, bowel, and solid organ involvement. Concomitant pulmonary and extra-pulmonary involvement was assessed.

RESULTS

Abdominal pain (78.1%) followed by fever (42.9%) were the commonest presenting symptoms. Peritoneal TB (77.14%) most commonly presented with a mix of ascites (49.38%), peritoneal (28.40%), and omental involvement (27.16%). Lymphadenopathy (57.1%) most commonly presented as necrotic nodes (81.67%) at mesenteric, peripancreatic, periportal, and upper paraaortic regions. Commonest site of bowel involvement (cumulative of 62.85%) was ileocecal region, with the commonest pattern of involvement being circumferential bowel wall thickening without bowel stratification with mild luminal narrowing. Hepatic (13.33%) and splenic (16.2%) involvement predominantly presented as multiple microabscesses. Adrenal and pancreatic involvement was noted in 4.7% and 1.9% of patients, respectively. 38.1% patients showed concomitant pulmonary and extra-pulmonary TB.

CONCLUSION

ATB has varied radiological features; however, peritoneal involvement in the form of mild ascites, smooth peritoneal thickening, smudgy omentum, multi-focal bowel involvement, necrotic nodes, and multiple visceral microabscesses point towards a diagnosis of ATB in appropriate clinical setting.

Tuberculosis (TB) of the Porta Hepatis Presenting with Obstructive Jaundice Mimicking a Malignant Biliary Tumor: A Case Report and Review of the Literature

Localized hepatobiliary tuberculosis (TB) is a rare disorder which can present with an obstructive jaundice mimicking other noninfectious causes such as cholangiocarcinoma. Here, we report a case of porta hepatis tuberculosis in 19-year-old female who presented with an obstructive jaundice, and her computed tomography (CT) of the abdomen revealed a hepatic hilar mass with radiological features mimicking a malignant biliary tumor. We also review the literature related to this disorder.

Isolated hepatobiliary tuberculosis: a diagnostic challenge

Hepatobiliary system involvement is frequently seen as part of disseminated tubercular infection. But primary isolated hepatobiliary tuberculosis with no evidence of tuberculosis elsewhere in the body is extremely rare. Isolated hepatobiliary tuberculosis can cause diagnostic dilemma as the clinical, laboratory and imaging features are non-specific in majority of the cases. We report the case of a 50-year-old woman who presented with hepatobiliary tuberculosis with no pulmonary or extra hepatic involvement. Liver function tests were abnormal and ultrasonography (USG), CT and MR cholangiopancreatography showed multiple focal lesions in the liver. The diagnosis of tuberculosis was confirmed by a USG-guided biopsy of the liver lesions. In endemic regions with the presence of supportive imaging findings, in the appropriate clinical setting, the possibility of hepatic tuberculosis should be considered and diagnosis has to be confirmed with histopathological examination.

Extrapulmonary involvement in pediatric tuberculosis

Tuberculosis in childhood is clinically challenging, but it is a preventable and treatable disease. Risk factors depend on age and immunity status. The most common form of pediatric tuberculosis is pulmonary disease, which comprises more than half of the cases. Other forms make up the extrapulmonary tuberculosis that involves infection of the lymph nodes, central nervous system, gastrointestinal system, hepatobiliary tree, and renal and musculoskeletal systems. Knowledge of the imaging characteristics of pediatric tuberculosis provides clues to diagnosis. This article aims to review the imaging characteristics of common sites for extrapulmonary tuberculous involvement in children.