Bilateral Vagus Nerve Neurolymphomatosis DiagnosedUsing PET/CT and Diffusion-Weighted MRI

Boasquevisque GS, MD,*Þ Guidoni J, MD,Þ Moreira de Souza LA, MD,Þ Goncalves PG, MD,þAndrade CV, MD, PhD,§ Pedras FV, MD,|| Boasquevisque EM, MD, PhD,* and Boasquevisque ETS, MD*

Abstract: In neurolymphomatosis, malignant lymphocytes infiltrate the pe-ripheral nervous system in the presence of a known or unknown hematologicalmalignancy. This report describes the findings of diffusion-weighted MRI and18F-FDG PET/CT in a 65-year-old man with hoarseness. Results revealed amass with restricted diffusion on diffusion-weighted imaging in the right vis-ceral vascular space, increased uptake of 18F-FDG, and other masses at distantperipheral nerves. Restaging PET/CT showed involvement of the right brachialplexus and right sciatic nerve. Biopsy and immunohistochemistry of the rightvagus nerve and cervical lymphadenopathy revealed a diffuse large B-cellnon-Hodgkin lymphoma.

Key Words: neurolymphomatosis, MRI, diffusion, PET/CT

(Clin Nucl Med 2012;37: e225Ye228)

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3. Haque S, Law M, Abrey LE, et al. Imaging of lymphoma of the central nervoussystem, spine and orbit. Radiol Clin North Am. 2008;46:339Y361.

4. Dong Q, Wong KK, Avram AM. Sacral nerve root neurolymphomatosis diag-nosed on FDG-PET/CT and magnetic resonance imaging. Clin Nucl Med. 2008;33:30Y31.

5. Hong CM, Lee SW, Lee HJ, et al. Neurolymphomatosis on F-18 FDG PET/CTand MRI findings: a case report. Nucl Med Mol Imaging. 2011;45:76Y78.

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Received for publication January 22, 2012; and revision accepted February 21, 2012.From the *Department of Radiology, National Cancer Institute, Ministry of Health;

Departments of †Radiology, ‡Oncology/Hematology, and §Pathology, HospitalSao Vicente de Paulo; and ||Department of Nuclear Medicine, Clınica Radi-ologica Luiz Felippe Mattoso, Rio de Janeiro, Brazil.

Conflicts of interest and sources of funding: none declared.Specific Information About Each Author:Gustavo Santos Boasquevisque: acquisition and interpretation of data of magnet

resonance images, drafting and revising the article, and final approval of theversion to be published.

Juliana Guidoni: acquisition and interpretations of data of magnet resonance images.Luis Alberto Moreira de Souza: interpretation of magnet resonance images.Patricia Guimaraes Goncalves: clinical oncologist, responsible for acquisition of

treatment data.Cecilia Vianna de Andrade: pathologist, responsible for specimen data revision.Felipe Vilella Pedras: acquisition and interpretation of data of PET/CT studies and

drafting and revising the article.Edson Mendes Boasquevisque: interpretation of data of magnet resonance images,

drafting and revising the article, and final approval of the version to be published.ElianaTeles SantosBoasquevisque: interpretation of data ofmagnet resonance images,

drafting and revising the article, and final approval of the version to be published.Reprints: Gustavo Santos Boasquevisque, MD, Rua Humaita, 244, Bloco 2/708,

Humaita, 22261-001 Rio de Janeiro, Brazil. E-mail: gsboas@gmail.com.Copyright * 2012 by Lippincott Williams & WilkinsISSN: 0363-9762/12/3709Ye225

Copyright © 2012 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.

FIGURE 1. A 65-year-old man was investigated for hoarseness. Laryngoscopy revealed paralysis of his right vocal cord, and clinicalexamination showed a palpable right cervical lymph node. T1- (A) and T2-weighted (B) MRI of the skull base in the axial planeandcontrast-enhanced T1-weighted fat-saturated images in the axial (C,D) and coronal (E) planes showan ill-defined, elongatedmassin the right vascular space between the internal carotid artery and the jugular vein. There was intermediate signal intensityinbothT1- andT2-weighted sequencesandhomogeneous enhancement extending through the cisternal segmentof thevagusnerve.These features are nonspecific, and diagnosis of a malignant peripheral nerve sheath tumor was considered. F to H, Lymph nodespecimen. F, Diffuse large B-cell lymphoma, not otherwise specified; hematoxylin-eosin staining; magnification, �100.G, Diffuse membrane labeling for CD20; magnification, �400. H, Few reactive lymphocytes labeled for CD3; magnification, �400.Neurolymphomatosis (NL) is a rare neurologic presentation of non-Hodgkin lymphoma (NHL) and leukemia and involvesneural infiltration by malignant lymphocytes.1,2 Neurolymphomatosis usually precedes the systemic disease and diagnosis of thecondition requires (1) histological demonstration of malignant lymphocytes within the peripheral or cranial nerve, root or plexus;or (2) radiologic or intraoperative evidence of nerve enlargement beyond the dural sleeve and/or enhancement in the presenceof a primary central nervous system lymphoma or systemic NHL. There are 4 major clinical presentations: painful polyneuropathyor polyradiculopathy, cranial neuropathy, painless peripheral polyneuropathy, and peripheral mononeuropathy.1 In 58% of cases,more than 1 anatomical structure is affected.2 Neurolymphomatosis is distinct from subarachnoid seeding or perineural infiltration ofan epidural lymphoma, inflammatory neuropathies, and neuropathic complications of treatment.1

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FIGURE 2. Restaging MRI performed 2 months later. AxialT1- (A), T2- (B), diffusion-weighted imaging (DWI) (C),apparent diffusion coefficient (D), contrast-enhancedT1-weighted imaging in the axial (E), and coronal planes withfat suppression (F) showing an increase in the size of thelesion in the right vagus nerve and a new lesion in the leftvagus nerve. Intermediate signal in T1- and T2-weightedimages, restricted diffusion, and homogeneous enhancementwere observed. MRI findings of enlarged neural structures withcontrast enhancement constitute the result most indicative ofthis diagnosis, with sensitivity of 40% to 70% when associatedwith a known history of NHL. MRI sensitivity is greater thanthat achievedwith cerebrospinal fluid analysis, which is reportedto range from 21% to 40%; however, sensitivity with boththese techniques is very low compared with the sensitivity of80% achieved with nerve biopsy.1,2 Restricted diffusion onDWI may serve to differentiate lymphoma from other tumorsbecause of its high cellularity.3 Concomitant findings atPET/CT and MRI in NL have already been published,4Y6 butto the best of our knowledge, this is the first case of NL showingrestricted diffusion on DWI and its association with PET/CT,which may be useful in defining diagnosis.

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FIGURE 3. PET/CT (A) and MRI fused with PET/CT (B) showincreased uptake bilaterally in the vagus nerves. PET/CT and 3Dvolume rendering technique (C, D) show increased uptake atthe visceral vascular spaces (long thin arrows), in left cervicallymphadenopathy (short thin arrow), at the projection of aparavertebral nerve root at the level of the lower thoracic spineand at the left lumbosacral plexus (short thick arrows). Thelesions shown in vascular spaces are in agreement with thefindings of the DW images (Figs. 2C, D). A restaging PET-CT and3D volume rendering technique (E, F) performed 7months latershow new sites of uptake involving the right brachial plexus(long thin arrow) and right lumbosacral plexus (short thinarrow) and improvement at the other sites, reflecting a mixedmetabolic response and progression of the disease, indicativeof significant intrapatient heterogeneity of gene expressionprofiles. If clinical presentation, cerebrospinal fluid analyses, andimaging studies are inconclusive, biopsy of neural tissue isrequired.1,2 The PET/CT sensitivity of 87% is helpful in diagnosingNL in the presence of a known hematological malignancy,even in the case of lesions in the subclinical phase and principallywhen the set of tests used for evaluation yield inconclusiveresults.2,5,7 The present case also demonstrates the usefulnessof FDG-PET/CT in NL for the evaluation of therapeutic response,as previously reported by Talanow and Shrikanthan.8

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