Isolated Hepatic Tuberculosis: A Difficult Diagnosis

Dear Editor,

We read with great interest the fascinating manuscript by Malewadkar et al¹ describing a case of isolated hepatic tuberculosis (TB) presenting with fever and chills and then developing bleeding into the abscess cavity, necessitating an emergency right liver resection.

In their patient, the ultrasound scan had showed a 6-cm right lobe liver abscess, however with no specific features. The computed tomography (CT) scan confirmed a 6.7-cm subcapsular and intraparenchymal mixed density fluid collection with solid components, epicentered in segments 6 and 7 of the liver.

The authors correctly stated that isolated hepatic abscess of tubercular origin is a rare cause of hemorrhage and should be considered because for the correct diagnosis, a microbiological assessment is always required.

They state that a triphasic CT scan of the liver with hepatic arterial, portal venous, and delayed phases is mandatory for the diagnosis of any space-occupying lesion within the liver and also suggest performing a dedicated and complete CT scan of the chest and the abdomen including the pelvis to rule out any other sites of TB.

However, we would like to add an additional consideration that this case in our opinion deserves to be more stressed with regard to the role of imaging in diagnosing hepatic TB.

Hepatic TB can be treated by conventional anti-TB therapy. However, it has been repeatedly reported that imaging lacks specific features and the likelihood of misdiagnosis is high.^{2, 3, 4}

In particular, also the triphasic CT scan and contrast-enhanced ultrasound could not correctly identify the TB nature of a focal liver lesion, as recently reported.⁴

This is particularly challenging in patients with a single liver lesion that could be misdiagnosed as liver cancer or other focal liver lesions. It has been reported that extrapulmonary TB represented 15% of the 7.0 million incidental cases that were notified in 2018, ranging from 8% in the Western Pacific Region to 24% in the Eastern Mediterranean Region.⁵

In our opinion, the case described by Malewadkar et al¹ further highlights that diagnosing hepatic TB remains a challenge.

The focal hepatic lesion's correct characterization in the case reported by Malewadkar et al¹ was challenging owing to bleeding, necessitating an emergency liver resection.

Moreover, neither ultrasound nor CT allows suspicion of a tubercular origin.

As reported in other studies, hepatic TB presenting as a single focal liver lesion may be misdiagnosed as liver tumors and only microbiological assessments such as polymerase chain reaction on the histological sample allow diagnosis and TB management.

Importantly, TB-specific symptoms are lacking.^{2, 3, 4}

In conclusion, we would like to highlight that owing to the lack of specific clinical manifestations and imaging features, a good knowledge of personal history and epidemiological data is mandatory in interpreting imaging findings of a focal liver lesion and for differential diagnosis, especially in patients from TB-endemic areas.

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Guarantor of the article

Markus Wilhelmi.

Abbreviations

CT: Computed tomography; HCC: Hepatocellular carcinoma; PCR: Polymerase chain reaction; TB: tuberculosis.

Author contributions

M.W. drafted the manuscript and reviewed the literature.

CRediT authorship contribution statement

Markus Wilhelmi: Conceptualization, Methodology, Data curation, Writing – original draft, Writing - review & editing.

Conflicts of interest

The author has none to declare.