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An asymptomatic 45-year-old man, with no relevant medical history, underwent an abdominal ultrasound that revealed a markedly hypoechoic focal liver lesion in S4b.
Contrast-enhanced multidetector CT (MDCT) was performed for further characterisation. The nodule displayed heterogeneous enhancement in the late arterial phase (figure 1A), with sustained enhancement in the portal venous and equilibrium phases (figure 1B,C). Six months after MDCT, a liver MR was performed using extracellular paramagnetic contrast. The liver showed steatosis (figure 1D,E) but no stigmata of chronic hepatopathy. The liver nodule had increased in size displaying low signal on T1-w images (figure 1D,E), high signal on T2-w (figure 1F) and a hyperintense central scar on T2-w. There was no signal change in the chemical shift sequence (figure 1D,E) and the restricted diffusion with low apparent diffusion coefficient was seen (figure 1G,H). The dynamic contrast-enhanced MR showed an intense blush at the late arterial phase with intralesional contrast retention and a faint peripheral rim enhancement (figure 1I–L). The nodule was deemed uncharacterised and the main differential diagnoses considered were such as hepatocellular carcinoma, inflammatory hepatocellular adenoma or hypervascular metastasis (renal cell carcinoma, thyroid carcinoma, neuroendocrine, sarcomas, melanoma).
A combination of positron emission tomography with 18F-labelled fluoro-2-deoxyglucose and CT (18F-FDG) was performed revealing hypermetabolic activity of the nodule (figure 1M) but no further lesions.
Based on the conjunction of imaging features, a malignant nature was foreseen and an ultrasound-guided core biopsy performed. The histopathological study revealed a follicular-type B-cell non-Hodgkin’s lymphoma. Since no extrahepatic foci of lymphoma were found with the imaging techniques preformed, the diagnosis of primary lymphoma of liver was made.
Primary lymphoma of the liver is considered when no extrahepatic disease is detected.1 It is a very rare neoplasm, corresponding to about 0.02% of non-Hodgkin lymphomas and 0.4% of extranodal lymphomas.2 Primary lymphoma of the liver usually presents as a unique lesion, hypoechogenic on ultrasound, hypodense on CT after contrast administration due its hypovascular nature. MR typical features include low signal on T1-w, high signal on T2-w and markedly restriction to diffusion. It usually has a discrete enhancement effect because of the hypovascular nature, with peripheral ring enhancement. Like other lymphomas, it has high uptake for 18F-FDG.1–3
This particular case, in addition to the rarity of the entity, presented as a diagnostic challenge given the hypervascular behaviour, clearly unusual for lymphomas. A core biopsy was essential for diagnosis and patient management.
Primary lymphoma of the liver is a rare neoplasm and can present as a hypervascular focal liver lesion.
Positron emission tomography with 18F-labelled fluoro-2-deoxyglucose/CT should be performed to rule out extrahepatic foci of lymphoma.
Core biopsy is mandatory to guide patient management.
Contributors LAF and JFC: concept, design, processing, writing manuscript and critical analysis. PD and FC-A: supervision, critical review of the manuscript and final approval of the version to be published.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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