Teaching Case

A 67-year-old man was admitted to the emergency department with complaints of painless jaundice, weight loss, and night sweats. The patient underwent several imaging tests (US, contrast-enhanced CT, MRI and FDG PET/TC) as well as histological, immunophenotypic and genetic analysis. 

Abdominal US revealed a hypoechoic periportal cuff surrounding the portal space from the hepatic hilum towards the periphery of both lobes (fig. 1).

CT demonstrated an infiltrative periportal mildly hypoenhancing and homogeneous mass, without evidence of necrosis or cystic changes. Mild intrahepatic biliary dilatation with a normal-caliber extrahepatic duct and few adenopathies in the hepatic hilum were also seen (fig. 2).

MRI was performed. The periportal cuff involvement was hypointense on T1- weighted, mildly hyperintense on T2-weighted, and showed marked restricted diffusion (fig. 3). The mass was hypoenhancing on contrast-enhanced MRI images. MR cholangiography revealed a diffuse dilatation of the biliary tree (fig. 4). 

Bone marrow biopsy showed diffuse infiltration by Burkitt Lymphoma (fig. 5).

PET/TC showed avid FDG uptake within the periportal mass. Diffuse bone marrow hypermetabolism was also demonstrated (Fig. 6). No evidence of morphological or functional disease after intensive therapy in the consecutive PET-TC scans (Fig. 6).

Burkitt lymphoma (BL) is a highly aggressive non-Hodgkin lymphoma (NHL) often presenting in extranodal sites or as acute leukemia. The hallmark of this disease is the overexpression of c-Myc, most commonly resulting from translocation (8;14) [1, 2].

Adult patients with sporadic or immunodeficiency–associated BL typically present with extranodal disease, with the abdomen being the most frequent site of involvement. It can affect the bowel or abdominal lymph nodes, although the implication of liver, spleen amongst others can occur [1].

Lymphomatous involvement of the liver is classified into primary or secondary hepatic lymphoma, the latter being by far the most common. NHL predominates in both forms [3].

Since the management and prognosis of lymphomas are significantly different from other malignancies, early diagnosis and prompt commencement of therapy are of paramount importance [2, 3]. Radiological and functional imaging, as well as biopsy and anatomopathological correlation together with immunophenotype are essential to reach the final diagnosis [3, 4].

Lymphomatous involvement of the liver can manifest on imaging as solitary or multiple nodular patterns, diffuse infiltration, or periportal soft tissue mass. A combination of these patterns can be seen in the same patient [3]. 

Periportal growth pattern is an uncommon condition with few cases reported in the literature [5]. It manifests as a periportal soft-tissue mass and is seen in both primary and secondary forms of hepatic lymphoma. Central biliary dilatation and transient hepatic attenuation differences may occur due to compression of the main branches of the hepatic duct and portal vessels, respectively [3, 4].

On US, the mass is usually hypoechoic. On contrast-enhanced TC or MRI it may be hypoenhancing. On MRI it shows a hypointense or isointense signal on T1WI and hyperintense signal on T2WI, and typically shows markedly restricted diffusion on DWI and ADC maps. Indeed, functional tissue information provided by diffusion-weighted MRI and ADC maps may be useful for detecting periportal involvement of lymphoma in subtle cases [5]. It shows avid FDG uptake on PET-TC, which is crucial to accurate staging of lymphomas and to assess therapy response or post-treatment recurrence [5].

Biopsy is required for definitive diagnosis [1, 2]. In our case bone marrow analysis provided sufficient information to reach the final diagnosis.

Chemotherapy together with adequate central nervous system prophylaxis are the treatment of choice and they can be curative even in the setting of advanced-stage disease [1].

Written informed patient consent for publication has been obtained.