Trigeminal Ganglioneuroma in the Middle-posterior Cranial Fossa: a Case Report

Chin Med Sci J June 2017

Vol. 32, No. 2 P. 123-128

CHINESE MEDICAL SCIENCES JOURNAL

CASE REPORT

Trigeminal Ganglioneuroma in the Middle-posterior Cranial Fossa: a Case Report△ Ting Wang1, Lin Ma1, Xin Lou1, and Bo Bu2* 1

Department of Radiology, 2Department of neurosurgery, Chinese PLA General Hospital, Beijing 100853, China

Key words: ganglioneuroma; trigeminal nerve; computed tomography; magnetic resonance imaging; middle-posterior cranial fossa Chin Med Sci J 2017; 32(2):123-128. DOI:10.24920/J1001-9294.2017.016

G exists,

1

ANGLIONEUROMA is considered as the most

discontinuous dizziness for one month. The dizziness was

mature and noninvasive form of neuroblastic

paroxysmal onset without obvious cause. General physical

tumors. It derives from neural crest cells, and

examination demonstrated right facial muscle atrophic,

can arise from wherever sympathetic tissue

with no other abnormality. All the neurologic examination

including neck, posterior mediastinum, adrenal

was negative.

gland, retroperitoneum and pelvis. The two most common

Computed tomography (CT) scan of the brain discov-

locations for this tumor are retroperitoneum and posterior

ered a slight hypodensity mass (4.2cm×5.2cm) in the right

mediastinum; infrequently it occurs in the intracranial re-

middle-posterior cranial fossa with internal high- density

gion,2-8 with only three cases has been reported arising

dots in the tumor (Fig. 1A). The tumor deformed the

from trigeminal nerve.2-4 The current paper presents a

ethmoid bone, destroyed the greater wing of the sphenoid

49-year-old male patient with a ganglioneuroma arising

bone and the petrous apex area, and extended to the

from right trigeminal ganglion and extending to the mid-

carvernous sinus and posterior cranial fossa. The pons was

dle-posterior cranial fossa. We summarized the clinical and

compressed. CT value of the spotty high-density was about

diagnostic characteristics of this extremely rare tumor, in

350HU, consistent with localized intratumoral calcification

comparison with the three reported cases in literatures.

and hemorrhage. CT images in bone window demonstrated absorption and thinning of the sphenoid and ethmoid bone

CASE DESCRIPTION

without destruction (Fig. 1B). The brain magnetic resonance imaging (MRI) showed a 4.1cm×5.4cm×4cm

A 49-year-old male patient with no previous comorbidi-

well-circumscribed extra-axial mass in the parasellar and

ties presented to our hospital with a main complaint of

cerebellopontine angle region of right middle-posterior cranial fossa (Fig. 2). The right fifth-sixth cranial nerve was

Received for publication June 6, 2016.

displaced by the mass. The lesion demonstrated hetero-

*Corresponding Tel: 86-13501227055，Fax: 86-10-68155902，E-mail:

geneous isointensity or slight hypointensity on T1-weighted

[email protected] △Supported by National Natural Science Foundation of China (81101034).

image (T1WI), heterogeneous hyper- to slight hypointensity on T2-weighted image (T2WI) (Fig. 2A). It compressed

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the right temporal lobe and pons, and caused the homo-

image (DWI), the lesion showed no diffusion restriction (Fig. 2E),

lateral masseter atrophic (Fig. 2B). On diffusion-weighted

and the lesion demonstrated heterogeneous hyperintensity

Figure 1. Images of cranial CT scan and postoperative MRI. A. A heterogeneous low-density mass in size of 4.2cm×5.2cm in the right middle-posterior cranial fossa with dotty calcification inside. B. Bone window image showed absorption and thinning of the sphenoid and ethmoid bone. C. Postoperative CT image demonstrated complete resection of the tumor. D-F. Postoperative MRI images (T2WI，T1WI, and enhanced T1WI) five months after the operation showed the tumor was resected completely with no residue and recurrence.

Figure 2．MRI findings on pre- and post-contrast MRI and diffusion-weighted imaging before operation. A. Axial T2WI image and B. Axial T1WI image showed a well-defined mass with heterogeneous signal intensity in the right middle-posterior cranial fossa. C. Remarkable heterogeneous enhancement on contrast enhanced axial T1WI. D. Coronal contrast enhanced T1WI image showed the lesion surround the right internal jugular vein. E. Diffusion-weighed imaging (b=1000 s/mm2) revealed a hypointensity tumor. F. Apparent diffusion coefficient mapping showed relatively hyperintensity of the tumor.

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with mean apparent diffusion coefficient (ADC) value of

which is consistent with the neurogenic nature of the tumor.

1.855×10

mm /s on ADC map (Fig. 2F). The solid part of

Staining of CD31, CD34, smooth muscle actin (SMA), vi-

the lesion demonstrated significantly enhanced and the

mentin were positive, epithelial membrane antigen (EMA)

cystic part showed no enhancement (Fig. 2C,D). Based on

was negative, and Ki-67 evaluation was positive in 3%,

the clinical history, location, CT and MR findings, the

confirming a benign neoplasm (Fig. 4D, 4E, 4F). The tumor

preoperative diagnosis was trigeminal neuroma, with dif-

was thus diagnosed as ganglioneuroma.

-3

2

ferential diagnosis of meningioma, acoustic neuroma or epidermoid cyst tumor.

Postoperative CT scan was performed on the fifteenth day after the surgery. It confirmed a completely resection,

The patient underwent a subsequent tumor resection

with no residue enhancement detected (Fig. 1D). Follow-up

through a preauricular subtemporal interdural approach.

MRI five months after operation demonstrated no residue

After the fronto-temporal craniotomy, the temporal dura

and no recurrence of the tumor (Fig. 1D-1F). There was no

was raised from skull base and dissected from the oph-

special event in the postoperative period，except external

thalmic (V1), the maxillary (V2), mandibular division (V3)

visual disturbance in the left eye.

and Meckel’s cave. The tumor located within the interdural space between the dura propria and inner membranous layer, which is a natural corridor for operation. The tumor

DISCUSSION

had partially grew into cavernous sinus with the main

Ganglioneuroma, accompanied with ganglioneuro-

body located in the Meckel’s cave (Fig. 3A). While sur-

blastoma and neuroblastoma, are classified as neuroblastic

geons piecemeal resected the tumor, cystic component of

tumor, which arise from neural crest cells in the peripheral

the intratumoral cavity was revealed (Fig. 3B). The tumor

nervous system.1 Unlike neuroblastoma or ganglioneuro-

was found partially adhering tightly to the abducens nerve,

blastoma that behave more invasively and usually occur in

and it originated from trigeminal ganglion. Tumor resec-

younger children, ganglioneuroma is well differentiated,

tion was performed piece by piece under microscope, and

benign, slow growing tumor that remains clinically silent

V2, V3 and abducens nerves were intact.

until it become large enough to cause symptoms by com-

Gross pathology revealed a rich blood supply, soft

pressing adjacent structures. Generally, it occurs in older

texture mass with smooth capsule. Histopathologic ex-

children and young adults,2,9 with about 80% of most se-

amination demonstrated the tumor was composed of

ries occurring in patients under 30 years old,3 with no

scattered large mature ganglion cells and schwann cells,

significant gender difference. However, recent studies have

with the presence of elongated or spindle shaped cells in an

shown that the ages at diagnosis of ganglioneuroma were

abundant collagenous stroma (Fig. 4A). Additionally, slight

around 40 to 50 years old.1,2,4,6 Up to now, the etiology of

dysplastic ganglion cell were observed in part of the tumor

ganglioneuroma has been unclear yet. Hayes et al. pointed

with binucleated cells accompanied (Fig. 4B). Calcification

out that ganglioneuroma may occur spontaneously or as a

and hyaline degeneration were revealed (Fig. 4C). Im-

result of either chemotherapy or radiation therapy for

munohistochemical stain showed positive for S-100 protein,

neuroblastomas.10 Retroperitoneum as well as posterior

Figure 3. Photographs of intra-operative findings. A. After the focal skull removed, the dura was exposed and extradural tumor was identifiable. B. Cystic component of the intratumoral cavity (asterisk). Maxillary and mandibular nerve were well reserved while the tumor was resected completely. V2, maxillary nerve; V3, mandibular nerve; T, tumor.

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Figure 4. Histological findings of ganglioneuroma. A. Mixture of large ganglion cells (arrows) and spindle-shaped Schwann-like cells (H&E staining, 400×). B. Dysplastic ganglion cell with binucleated cell (arrow) (H&E staining, 400×). C. Calcification (arrow) and hyaline degeneration (asterisk) in tumor (H&E staining, 100×). D. S-100 positive cells accompanied with giant ganglion cells (arrows) supporting the neurogenic nature of the tumor (S-100 protein immunohistochemical staining, 400×). E. CD34 positive cells presented in blood vessels, indicating angiogenesis of the tumor (CD34 immunohistochemical staining, 400×). F. 3% Ki-67 positive cells confirmed the benign neoplasm (arrows) (Ki-67 immunohistochemical staining, 400×).

mediastinum are the two typical locations for gan-

3%, which highly support benign tumor. In our case, the

glioneuroma, yet it is rarely seen in spinal cord, cranial

final pathological examination confirmed the diagnosis.

nerve ganglia, mandible, tongue, parapharyngeal tissue,

Although diagnosis of ganglioneuroma mainly depends

gastrointestinal tract, bladder, visceral ganglia, uterus,

on histopathologic assessment, CT and MRI scan provide

ovary, spermatic cord, testes, prostate, skin, and bone.9

information in location, size, component of the mass, and

Intracranial ganglioneuroma is extremely rare. It has been

its relationship to adjacent significant structures, which is

reported with only three cases arising from trigeminal

valuable in determining a surgical plan. On CT imaging,

nerve.

Some other intracranial locations as reported

ganglioneuroma often shows well-defined, low-density le-

were internal auditory canal (IAC) and middle ear.5-8 The

sion with punctate calcification.9 It is reported that ap-

case we report here is the fourth description of gan-

proximate 20%-42% ganglioneuroma is accompanied with

glioneuroma originating from trigeminal nerve.

calcification.9 Ichikawa et al. believe that the morphology

2-4

Histopathologically, ganglioneuroma is composed of

of calcifications can served as a key characteristic to dif-

single or clustered mature, giant ganglion cells and

ferentiate benign tumor from malignancies.13 Scattered

Schwannian stroma. It usually has no components of

punctate or grain-like calcification indicates benign lesion,

neuroblasts, intermediate cells, or mitotic figures that in-

while large patchy or irregular calcification implies malig-

dicating malignant differentiation. According to interna-

nancy. In our case, punctate calcifications was seen in the

tional neuroblastoma pathology classification of neuro-

lesion, which indicate a diagnosis of benign, although the

blastic tumors, ganglioneuroma has been divided into two

patient only took a plain CT scan without contrast en-

subtypes: maturing and mature subtype.9 Typical gan-

hancement. On MRI, typical ganglioneuroma manifest as

glioneuroma is composed of mature ganglion cells and

well-circumscribed mass with low signal on T1WI, heter-

schwannian stroma; however, tumor with entirely matu-

ogeneous high signal on T2WI, and progressive en-

rated ganglion cells are rare (approximately 7%). In the

hancement on dynamic contrast-enhanced images .13 MRI

present patient, lightly atypical ganglion cell with binu-

is superior to CT in showing blood vessels surrounding and

cleated cell was detected. The immaturity of ganglion cells

compressing.

9

did not affect the diagnosis of ganglioneuroma.11 Im-

The three cases reported were derived from trigeminal

munohistochemically, it is characterized by reactivity for

nerve. In 1999, Abe et al 3 firstly reported an 8-year-old girl

12

S-100, vimentin, synaptophysin and neuronal markers.

who presented ganglioneuroma in the left cerebellopontine

Ki-67 is also a immunomarker of cellular proliferation. In

angle region, which originated from the sensory root of the

this patient, Ki-67 positive cells of the tumor are as low as

trigeminal nerve. The tumor was a well-circumstanced

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mass with hypo-intensity on T1WI, hyper-intensity on

dermoid cyst is typically diffusion restricted on DWI

T2WI, and relatively homogenous enhancement on post-

compared with brain parenchyma, with no or minimal

contrast image. Another case reported by Nakaguchi et al4

margin enhancement. Meningioma often shows iso-intense

in 2012 was a 55-year-old man with sudden onset of severe

on T1WI and T2WI, with homogenous enhancement.

headache. MR images of this patient demonstrated a slight

Neurofibromatosis type 2 and metastasis always present as

high T2 signal and obviously heterogeneously enhanced

multiple, enhanced lesions, associate with a family or

lesion in the left middle cranial fossa. The latest case re-

clinical tumor history.

ported in 2013, was an iso-intensity on T1WI and slight

It is general accepted that surgical resection alone is

hyper-intensity on T2WI, with a minimal enhancement. In

curative for ganglioneuroma, while radiotherapy is not

our case, the mass showed slight hypointensity on T1WI

recommended, despite potential risk for malignant trans-

and heterogeneous hyperintensity on T2WI. The different

formation to neuroblastoma.9 With complete resection of

signal intensity on T2WI among these rare cases may due

ganglioneuroma, the patient usually can achieve a good

to the proportions of cellular quantity, fibrous components

prognosis.

and myxoid stroma.14 The histopathology of our case con-

In summary, we described a benign and extremely rare

firmed high proportion of hyaline degeneration among the

trigeminal ganglioneuroma, which was lack of specific

stroma of the tumor. Besides, significant heterogeneous

imaging characteristic, and were difficult to diagnose be-

enhancement of the tumor was consistent with the case

fore operation. Finial diagnosis depends on pathology.

Nakaguchi et al reported, but didn’t accord with the other

When imaging features don’t absolutely support any

two cases. Based on above four cases，we proposed that

common diagnosis, trigeminal ganglioneuroma should be

the enhancement pattern of ganglioneuroma on MR image

considered as a possible diagnosis. The prognosis of sur-

vary from mild to marked.

gical excision of the tumor is favorable.

The apparent diffusion coefficient (ADC)，regarded as a quantitative index of diffusion function of water in the

Conflict of Interest Statement

tumor on diffusion weighted imaging(DWI) ， has been

The authors have no conflicts of interest to disclose.

described for intracranial ganglioneuroma only in one report2, where the mass showed homogeneous hyperintense

Acknowledgments

on DWI image, with a mean ADC value of 0.72×10-3 mm2/s.

We would like to acknowledge Quiping Gui, at the de-

In our case, the mean ADC value presented as 1.855×10-3

partment of pathology, PLA General Hospital of China, for

mm /s, which is relatively high, but is consistent with the

her assistance in pathology.

2

measurement in Gahr’s study for thoracoabdominal ganglioneuromas/ganglioneuroblastomas (mean ADC: 1.60×

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