Diffuse Large B-cell Lymphoma With Tumor Thrombus in the Superior Mesenteric Vein: A Case Report

Intravascular tumor thrombus, also referred to as tumor thrombus, is a well-recognized finding in various solid organ malignancies.Although rare, there have also been several case reports of tumor thrombus in malignant lymphoma.We report a case of diffuse large B-cell lymphoma (DLBCL) presenting as a mesenteric mass with tumor thrombus involving the superior mesenteric vein (SMV).A 76-year-old woman presented with abdominal pain.Contrast-enhanced computed tomography (CT) revealed a well-defined, lobulated mesenteric mass with heterogeneous enhancement.A tumor thrombus extending into the SMV was also identified.Fluorine-18 fluorodeoxyglucose positron emission tomography/CT demonstrated intense fluorodeoxyglucose uptake in both the mesenteric tumor and the SMV tumor thrombus (maximum standardized uptake value = 45.9).Based on these clinical and imaging findings, malignant lymphoma was considered the leading diagnosis.A CT-guided core needle biopsy was performed, and DLBCL was confirmed histopathologically.Although rare, malignant lymphoma can present with tumor thrombus.Failure to consider malignant lymphoma before biopsy may result in inadequate tissue sampling and inappropriate specimen handling, particularly because fresh tissue is required for immunophenotypic and genetic analyses.This may lead to delayed or inaccurate diagnosis.Therefore, malignant lymphoma should not be excluded from the differential diagnosis solely because tumor thrombus is present.