Accurate Detection of Tumor Infiltration by ¹¹C-Methionine Positron Emission Tomography in a Patient with Central Nervous System Intravascular Lymphoma: A Case Report

Abstract

Intravascular lymphoma (IVL) is a rare and clinically devastating subtype of extranodal diffuse large B-cell lymphoma with a distinct presentation. Diagnostic difficulty derives from marked variability in clinical presentations and nonspecific laboratory and radiological findings, especially when central nervous system (CNS) symptoms are the only manifestation. Establishing the diagnosis premortem thus remains a major challenge. We describe a 70-year-old male with CNS IVL. He presented with acute onset of neurocognitive impairments. Diffusion-weighted magnetic resonance imaging (MRI) showed multiple high-intensity areas suggesting occlusive cerebrovascular disease due to emboli, but extensive investigations detected no embolic sources. Intracranial neoplasm was included in a differential diagnosis based on elevated serum lactate dehydrogenase and interleukin 2 receptor levels. Gadolinium-enhanced MRI or 18-fluorodeoxyglucose positron emission tomography (PET) failed to demonstrate specific findings leading to a definite diagnosis, while ¹¹C-methionine PET (MET-PET) distinctively demonstrated an area of focally increased MET uptake in the frontal cortex, suggesting the extent of tumor infiltration. Stereotactic biopsy was conducted under MET-PET imaging guidance and immunohistological examinations confirmed the proliferation and aggregation of CD20-positive lymphoma cells within the lumina of small blood vessels. The findings of the present case first suggest that MET-PET may provide important information on the diagnosis of CNS IVL and on the selection of the optimal site for brain biopsy. Further investigation is necessary to clarify whether positive findings on MET-PET are truly specific and pathognomonic for CNS IVL.

PET findings in lymphomatosis and gliomatosis of the brain: a comparison of C-11 methionine PET/CT and F-18 FDG PET/CT

“…The lack of FDG uptake may be associated with the low cellularity of the tumor. However, in four cases of intravascular lymphoma previously examined using FDG-PET (3,15,16), three cases showed increased activity in all or part of the lesion.…”

“…Similar to gliomatosis cerebri, lymphoma can on rare occasions infiltrate large areas of the hemispheres without forming any mass, representing lymphomatosis cerebri (2). Intravascular lymphoma is characterized by intravascular growth of tumor cells, mimicking cerebral infarction or subacute encephalopathy (3). Magnetic resonance imaging (MRI) and computed tomography (CT) findings of gliomatosis (4), lymphomatosis, and intravascular lymphoma (3) mimic cerebral infarction and whitematter disorders, including multiple sclerosis, or other degenerative disorders.…”

Rare central nervous system lymphomas

“…118 Positron emission tomography has been described as a potentially useful diagnostic tool, 119 particularly the 11 C-methionine radionuclide, which seems to be able to identify IVL CNS lesions when MRI appearances resemble vasculitis. 120 CSF examination offers little aid in diagnosis, as neoplastic cells are frequently absent. 121,122 Brain biopsy histopathology reveals arrays of intravascular CD20 cells with MUM1 expression in 75%-80% of cases (Figure 6).…”

“…As such, IVL with CNS involvement should be included in the differential of rapidly progressive neurological symptoms with ischaemic MRI changes in the absence of cardiovascular risk factors 118 . Positron emission tomography has been described as a potentially useful diagnostic tool, 119 particularly the 11 C‐methionine radionuclide, which seems to be able to identify IVL CNS lesions when MRI appearances resemble vasculitis 120 …”

18F-THK5351 PET Can Evaluate Tumor Extension in Intravascular Large B-Cell Lymphoma

“…9 18 F-FDG PET was helpful in IVLBCL diagnosis only in some cases. [8][9][10][11] This discrepancy likely stems from the differences in the degree of extravascular infiltration of lymphoma cells and the density of lymphoma cells filling the vascular lumina, 8 leading to extensively variable appearance upon imaging. To our knowledge, this is the first case of IVLBCL on 18 F-THK5351 PET.…”