Contrast-Enhanced Ultrasonography in Diagnosing Intravascular Large B-Cell Lymphoma Infiltrating Liver Sinusoids

Objective: Rare disease Background: Intravascular large B-cell lymphoma (IVLBCL) is a rare extranodal large B-cell lymphoma characterized by the selective growth of lymphoma cells within vasculature. This presents a diagnostic challenge due to non-specific symptoms and lack of tumor formation. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) provides useful information in diagnosing FDG-avid lymphoma, but is not specific to IVLBCL. Contrast-enhanced ultrasonography (CEUS) is useful in evaluating focal liver lesions; however, its efficacy in diagnosing IVLBCL involving the liver remains unknown. Case Report: We report the case of an 83-year-old woman presenting with fever, pancytopenia, liver dysfunction, and elevated LD and soluble interleukin-2 receptor levels. PET-CT showed multiple uptake lesions in the liver. We performed CEUS with Sonazoid (R) to evaluate the mass-like lesions; however, no nodular lesions were observed in B mode images. Systemic enhancement was seen in the early phase but no defect was observed in the postvascular phase. The latter finding suggested preserved Kupffer cells function, excluding tumor-forming lymphoma and liver metastases. Suspecting IVLBCL, we performed a bone marrow examination, which showed sinusoidal infiltration of large neoplastic cells positive for CD20. The patient's condition deteriorated rapidly and she died 2 days after the examination. Autopsy revealed diffuse infiltration of lymphoma cells into liver sinusoids with preserved Kupffer cells, leading to the diagnosis of IVLBCL. Conclusions: Our case shows that CEUS can distinguish IVLBCL from mass-forming lymphoma based on the absence of a defect in the post -vascular phase in a patient with clinically and radiographically suspected lymphoma involving the liver. This can assist clinicians to select appropriate lesions for biopsy.