BACKGROUND: A preoperative diagnosis of primary hepatic lymphoma (PHL) can have profound therapeutic and prognos-tic implications. Because of the rarity of PHL, however, there are few reports on diagnostic imaging.We reviewed the clinical and radiologic findings of 29 patients with PHL, the largest series to date, to evaluate the diagnostic features of this disease.
METHODS: Clinical data and radiologic findings at presen-tation were retrospectively reviewed for 29 patients with pathologically confirmed PHL from January 2005 to June 2013. Imaging studies, including ultrasound (US) (n=29) and contrast-enhanced computed tomography (CECT) (n=24), were performed within 2 weeks before biopsy or surgery.
RESULTS: Among the 29 patients, 23 (79%) were positive for hepatitis B virus (HBV) and 26 (90%) had a significantly ele-vated level of serum lactate dehydrogenase (LDH). There were two distinct types of PHL on imaging: diffuse (n=5) and nodu-lar (n=24). Homogeneous or heterogeneous hepatomegaly was the only sign for diffuse PHL on both US and CECT, without any definite hepatic mass. For the nodular type, 63% (15/24) of patients had solitary lesions and 38% (9/24) had multiple lesions. On US, seven patients displayed patchy distribution with an indistinct tumor margin and a rich color flow signal. CECT showed rim-like enhancement (n=3) and slightly ho-mogeneous or heterogeneous enhancement (n=14) in the arte-rial phase and isoenhancement (n=5) and hypoenhancement (n=12) in the portal venous and late phases. Furthermore, in five patients, CT revealed that hepatic vessels passed through the lesions and were not displaced from the abnormal area or appreciably compressed.
CONCLUSIONS: The infiltration type of PHL was associated with the histologic subtype. Considered together with HBV positivity and elevated LDH, homogeneous or heterogeneous hepatomegaly may indicate diffuse PHL, whereas patchy dis-tribution with a rich color flow signal on US or normal vessels extending through the lesion on CECT may be the diagnostic indicators of nodular PHL.