Hepatic tuberculosis: a multimodality imaging review
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We aim to illustrate the multimodal imaging spectrum of hepatic involvement in tuberculosis (TB). Whilst disseminated tuberculosis on imaging typically manifests as multiple small nodular lesions scattered in the liver parenchyma, isolated hepatic tuberculosis remains a rare and intriguing entity.
Indubitably, imaging is the mainstay for detection of tubercular hepatic lesions which display a broad spectrum of imaging manifestations on different modalities. While sonography and computed tomography (CT) findings have been described in some detail, there is a paucity of literature on magnetic resonance imaging (MRI) features. Due to a significant overlap with other commoner and similar appearing hepatic lesions, hepatic tuberculosis is often either misdiagnosed or labelled as indeterminate lesions. This article is a compendium of cases highlighting the spectrum of imaging patterns that can be encountered in patients with isolated primary hepatic tuberculosis as well as disseminated (secondary) disease. Rare patterns of primary disease such as tubercular cholangitis, hypervascular liver masses, and those with vascular complications are also illustrated and discussed.
Imaging plays a valuable role in the detection of tubercular hepatic lesions. Also, imaging can be helpful in their characterisation and for assessing associated complications.
• Hepatic TB has myriad imaging manifestations and is often confounded with neoplastic lesions.
• Imaging patterns include miliary TB, macronodular TB, serohepatic TB and tubercular cholangitis.
• Concurrent splenic, nodal or pulmonary involvements are helpful pointers towards the diagnosis.
• Miliary calcifications along the bile ducts are characteristic of tubercular cholangitis.
• Histological/microbiological confirmation is often necessary to confirm the diagnosis.
KeywordsCT Hepatic tuberculosis Miliary Nodular Tubercular cholangitis, MRI
Tubercular infection constitutes one of the foremost causes of death and morbidity across the world, more so in the tropical region. With the emergence of HIV and AIDS, the disease that was thought to be endemic to emerging nations has become pandemic in nature [1, 2, 3]. Approximately 15% of people infected with HIV are co-infected with tuberculosis, pulmonary as well as extra-pulmonary in distribution, thus making the disease one of the leading causes of death in this population [4, 5].
Tubercular involvement of the liver is more commonly a part of disseminated disease wherein the hepatic parenchyma shows a diffuse pattern of involvement in the form of multiple small-sized miliary nodules. In contrast, isolated hepatic tuberculosis is seldom encountered in clinical practice with only a few sporadic cases and short series available in the current literature [6, 7, 8, 9].
Although there is no standard classification system available for hepatic tuberculosis, Levine  classified hepatic involvement in tuberculosis into five patterns: miliary tuberculosis, concomitant hepatic and pulmonary disease, primary (isolated) hepatic tuberculosis, tubercular hepatic abscess, and tubercular cholangitis. Also, there is a pathological classification with radiological correlation wherein Yu et al.  classified the disease into three forms: parenchymal type (which is further subclassified into micronodular and macronodular patterns), serohepatic disease and tubercular cholangitis.
Hepatobiliary tuberculosis most commonly affects people in the 11– to 50-year-old age group with the peak incidence of the disease reported in the second decade of life . The disease has a 2:1 male preponderance. Isolated hepatic tuberculosis is however more common in the fourth to sixth decades of life [7, 12, 13].
Generally, the disease remains silent and is often incidentally detected while the patient is being evaluated for a mostly non-specific symptomatology. It may however present in the form of abdominal pain or organomegaly which may or may not be associated with clinical jaundice. Jaundice if present is usually a consequence of extrahepatic biliary obstruction secondary to attendant periportal lymphadenopathy [14, 15].
Laboratory analysis may reveal altered liver function tests in the form of elevated hepatic enzymes. The elevation of alkaline phosphatase can be seen in jaundiced as well as non-jaundiced patients. In the event of isolated elevation of the alkaline phosphatase the possibility of tubercular hepatic parenchymal involvement must be excluded [11, 13].
The imaging manifestation of the tubercular hepatic disease can be wide ranging but can be broadly categorised into miliary pattern, nodular tuberculosis with serohepatic variant and tubercular cholangitis. As imaging pattern is largely non-specific, a histopathological or bacteriological confirmation is often required.
Tubercular hepatic lesions that are more than 2 cm in size are referred to as macronodular or pseudotumoral tuberculosis. This form of hepatic tuberculosis is rare compared to the miliary variant and frequently manifests as solitary or multiple variable-sized hepatic masses. Often it may be difficult to distinguish these lesions from the more common neoplastic and other infective lesions. Depending on the stage of the hepatic granuloma, the imaging appearances can be quiet variable [6, 7, 8, 9, 10, 21].
Hepatic tuberculosis has many faces and the imaging manifestation can show a considerable overlap with other relatively more frequent primary or secondary lesions of the liver. Isolated hepatic involvement by tuberculosis can especially be challenging to diagnose on imaging alone due its largely non-specific imaging features. Nevertheless, in endemic countries and in appropriate clinical settings an atypical imaging pattern of a hepatic lesion should prompt the radiologist to consider hepatic tuberculosis as one of the differential considerations. Although image-guided biopsy is usually required for a confirmatory diagnosis the presence of calcifications and the concurrent involvement of extrahepatic sites (spleen, lungs and nodes) should prompt the possibility of hepatobiliary tuberculosis.
- 2.Kakkar, Koteshwara P, Polnaya AM, Rajagopal K et al (2011) Imaging patterns of hepuberculosis on MDCT: Can we predict the diagnosis? Available on the Electronic Poster Online System (EPOS) of the European Society of Radiology. doi: 10.1594/ecr2011/C-0873
- 4.World Health Organization (2011) WHO Report: Global tuberculosis control? WHO, GenevaGoogle Scholar
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