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

18 F-THK5351 PET Can Evaluate Tumor Extension in Intravascular Large B-Cell Lymphoma : Comparison With 11C-Methionine PET and 18F-FDG PET

ABSTRACT

A 79-year-old man presenting with gait disturbance and cognitive decline was diagnosed with intravascular large B-cell lymphoma (IVLBCL) by random skin biopsy. Some IVLBCL lesions were identified by PET examinations using 11 C-methionine, 18 F-FDG, and 18 F-THK5351. 11 C-methionine and 18 F-FDG uptake, which likely reflects the presence of the lymphoma cells themselves, increased clearly in the left putamen but weakly in the left deep white matter. 18 F-THK5351 uptake increased in all lesions, likely reflecting perivascular astrogliosis caused by IVLBCL. Hence, 18 F-THK5351 PET can evaluate tumor extension in IVLBCL lesions where 11 C-methionine and 18 F-FDG PET may fail in its visualization.

Rare central nervous system lymphomas

Central nervous system (CNS) lymphomas are rare malignancies characterised by lymphoid infiltration into the brain, spinal cord, cranial nerves, meninges and/or eyes in the presence or absence of previous or concurrent systemic disease. Most CNS lymphomas are of the diffuse large B-cell lymphoma (DLBCL) subtype for which treatment strategies, particularly the use of high-dose methotrexate-based protocols and consolidation with autologous stem cell transplantation, are well established. Other histopathological subtypes of CNS lymphoma are comparatively less common with published data on these rare lymphomas dominated by smaller case series and retrospective reports. Consequently, there exists little clinical consensus on the optimal methods to diagnose and manage these clinically and biologically heterogeneous CNS lymphomas. In this review article, we focus on rarer CNS lymphomas, summarising the available clinical data on incidence, context, diagnostic features, reported management strategies, and clinical outcomes.

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

BACKGROUND

Positron emission tomography (PET) findings for gliomatosis and lymphomatosis have been rarely reported.

PURPOSE

To compare PET/computed tomography (CT) findings using ¹¹C-methionine (MET) from PET/CT findings using ¹⁸F-fluorodeoxy glucose (FDG) for patients with lymphomatosis or gliomatosis of the brain.

MATERIAL AND METHODS

Participants comprised all 10 patients with lymphomatosis or gliomatosis of the brain treated at our institution in the past 12 years. Underlying pathologies comprised intravascular lymphoma (n = 1), lymphomatosis (n = 3), and gliomatosis (n = 6). All cases were pathologically diagnosed. In seven patients, both MET-PET/CT and FDG-PET/CT were performed simultaneously in a single study. In three patients, only FDG-PET/CT was performed. The degree of tracer accumulation to the lesion was evaluated qualitatively. Quantitatively, the ratio of maximum standard uptake value (SUV_max) in tumor to that in normal tissue (T/N ratio) was measured and compared between FDG and MET.

RESULTS

Qualitatively, MET accumulated to part of the lesion in six of seven patients and almost all of the lesion in one in seven patients. FDG accumulated to part of the lesion in three of ten patients and almost all of the lesion in one of ten patients. No FDG accumulation was seen in the lesion in six patients. Quantitatively, mean ± SD T/N ratio was significantly higher with MET (2.11 ± 0.63) than with FDG (1.18 ± 0.84; P < 0.05, Wilcoxon signed-rank test).

CONCLUSION

In lymphomatosis and gliomatosis, FDG accumulates in only part of the lesion. FDG is thus less suitable than MET for depicting these lesions.