Clinical utility of positron emission tomography leading to rapid and accurate diagnosis of intravascular large B-cell lymphoma presenting with the central nervous system symptoms alone: A case report and review of the literature

Abstract

Background: Intravascular large B-cell lymphoma (IVLBCL) is a rare entity among large B-cell non-Hodgkin lymphomas and is often difficult to diagnose. We report the case of a patient with IVLBCL who presented with central nervous system (CNS) symptoms alone, in which positron emission tomography (PET) enabled a rapid and accurate diagnosis.

Case description: An 81-year-old woman was admitted to our hospital with a 3-month history of gradually progressive dementia and declining spontaneity. Magnetic resonance imaging revealed multiple hyperintense lesions bilaterally on diffusion-weighted imaging without enhancement on gadolinium-enhanced T1-weighted imaging. Laboratory findings showed elevated serum lactate dehydrogenase (626 U/L) and soluble interleukin-2 receptor (sIL-2R) (4692 U/mL). Cerebrospinal fluid (CSF) analysis showed slightly elevated levels of protein (166 mg/dL) and lymphocytic cells (29/μL), and β2-microglobulin (β2-MG) (4.6 mg/L) was highly elevated. Whole-body computed tomography revealed faint ground-glass opacities in the upper and middle lung fields and diffuse enlargement of both kidneys without lymph node swelling. ¹⁸F-fluorodeoxyglucose (FDG)-PET showed diffuse and remarkably high FDG uptake in both upper lungs and kidneys without uptake by lymph nodes, suggesting a malignant hematological disease. IVLBCL was confirmed histologically by incisional random skin biopsy from the abdomen. Chemotherapy using R-CHOP regimen in combination with intrathecal methotrexate injection was started on day 5 after admission and follow-up neuroimaging showed no signs of recurrence.

Conclusion: IVLBCL presenting with CNS symptoms alone is rare and often has a poor prognosis associated with delayed diagnosis, and various evaluations (including systemic analysis) are therefore necessary for early diagnosis. FDG-PET, in addition to identification of clinical symptoms and evaluation of serum sIL-2R and CSF β2-MG, enables rapid therapeutic intervention in IVLBCL presenting with CNS symptoms.

Keywords: 18F-fluorodeoxyglucose; Intravascular large B-cell lymphoma; Positron emission tomography; R-CHOP; Random skin biopsy.

Figure 1:

Magnetic resonance imaging findings of the brain. Axial diffusion-weighted imaging (a-1 - a-2) and fluid-attenuated inversion recovery imaging (b-1 - b-2) obtained at admission reveal multiple hyperintense lesions bilaterally in the periventricular white matter, centrum semiovale, and corpus callosum. T1-weighted imaging (c-1 - c-2) acquired after injection of gadolinium contrast medium shows no enhancement of the lesions.

Figure 2:

Axial computed tomography (CT) of the chest (a-1 - a-3) shows faint diffuse ground glass opacities in the upper and middle lung fields bilaterally. 18 F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) (b-1 - b-3) reveals slightly diffuse FDG uptake in the upper and middle lung fields bilaterally without uptake by lymph nodes. CT of the abdomen (c) demonstrates diffuse enlargement of both kidneys without lymph node swelling. FDG-PET (d) shows remarkably high FDG uptake in both kidneys.

Figure 3:

Histopathology of the resected lesion by random skin biopsy. Pathologic specimen (a and b) shows occlusion of small vessels by neoplastic cells with prominent nucleoli within subcutaneous adipose tissue. Tumor cells show positive staining for CD20 (c) and negative staining for CD3 (d). Magnification: (a) ×200; (b-d) ×400. Scale bars, 100 μm.

Figure 4:

Brain magnetic resonance imaging (MRI) findings at 1 month after admission. The multiple high-intensity lesions apparent on MRI obtained at admission have decreased on diffusion-weighted imaging (a-1 - a-2), and no new lesions are identified on fluid-attenuated inversion recovery imaging (b-1 - b-2) and gadolinium-enhanced T1-weighted imaging (c-1 - c-2).

Figure 5:

Whole body computed tomography (a-1 - a-3 and c) and ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography (b-1 - b-3 and d) obtained after three cycles of chemotherapy show complete disappearance of the abnormal signs and FDG accumulation identified on admission, indicating achievement of complete remission.