orbital schwannoma with cystic degeneration

Original Article

Orbital schwannoma with cystic degenerationSeema Kashyap MD,1 Neelam Pushker MD,2 Rachna Meel MS,2 Seema Sen MD,1 Mandeep S. Bajaj MD,2

Noornika Khuriajam MD,2 Mridula Mehta MS DNB2 and Bhavna Chawla MS2

1Ocular Pathology Services, and 2Oculoplastics and Ocular Oncology Services, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AllIndia Institute of Medical Sciences, Ansari Nagar, New Delhi, Indiaceo_2029 293..298

ABSTRACT

Background: Schwannoma is a benign, slowlygrowing, painless, peripheral nerve sheath tumourthat is uncommon in orbit. Longstanding tumoursmay develop degenerative changes. Extensive cysticchange in orbital schwannoma is quite rare. We con-ducted this study to analyse the cases of orbital schw-annoma, which were predominantly cystic anddescribe their clinical, imaging and histopathologicalfeatures.

Method: A retrospective analysis of histopathologyrecords of all the orbital tumours operated between1993 and 2008 was undertaken at a tertiary carereferral centre in northern India. The clinical,imaging and histopathological features of patientswith cystic schwannoma were studied.

Results: A total of 600 specimens of orbital tumourswere received during the study period. We found 39cases of orbital schwannoma. Out of these, 16 (41%)had extensive cystic degeneration. The age of thesepatients ranged from 20 to 65 years. Eleven of thepatients were female. Duration of symptoms variedfrom 3 months to 15 years. The most common clini-cal symptom was painless progressive proptosis withdiminution of vision. The radiological picture wasquite variable resulting in a primary diagnosis ofcombined venous-lymphatic vascular malformationin 2, lacrimal gland tumour in 2, dermoid cyst in 1,hydatid cyst in 2 and schwannoma in 5 cases.

Conclusion: Orbital schwannoma is a great masquer-ader in the orbit. Extensive cystic changes inschwannoma are uncommonly reported. Cystic

schwannoma constituted 41% of all orbital schwan-nomas in our series. To the best of our knowledge,this is the largest case series of orbital cysticschwannomas.

Key words: cystic degeneration, histopathology, orbitaltumours, proptosis, schwannoma.

INTRODUCTION

Schwannomas constitute around 1% of all orbitaltumours.1 They are well encapsulated, non-invasive,benign tumours that may arise any where in theorbit. Most commonly, they arise from the supraor-bital and supratrochlear nerves, and hence involvethe superior orbit. The patients are young to middle-aged with no sex predominance. They usually causea slowly progressive, painless proptosis associatedwith decrease in vision.1 Rarely, there may be numb-ness or pain along the involved nerve.2

Few cases of cystic schwannoma have beenreported in brainstem,3 intracranial nerves,4,5

adrenals6 and orbit.7–13 There is no pathognomonicclinical or imaging feature. In most cases diagnosis ismade on histopathology. The exact mechanism ofcystic degeneration is not known. It is hypothesizedthat necrosis within the tumour due to thrombosis ofdegenerating blood vessels, haemorrhage within thetumour with blood resorption or hyaline degenera-tion causes cyst formation. It has been speculatedthat the coalescence of mucinous or microcystic areasin Antoni B areas may result in cyst formation.7,10

Herein, we report clinical, imaging and histo-pathological features of 12 cases of orbital schwan-nomas with cystic changes, which, to the best of ourknowledge, is the largest case series till date.

� Correspondence: Dr Neelam Pushker, Oculoplastic and Paediatric Ophthalmology Services, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All

India Institute of Medical Sciences, Ansari Nagar, New Delhi 110 029, India. Email: [email protected]

Received 25 September 2008; accepted 4 March 2009.

Clinical and Experimental Ophthalmology 2009; 37: 293–298 doi: 10.1111/j.1442-9071.2009.02029.x

© 2009 The AuthorsJournal compilation © 2009 Royal Australian and New Zealand College of Ophthalmologists

mailto:[email protected]

METHODS

A retrospective analysis of histopathology records oforbital tumours operated between 1993 and 2008was undertaken at a tertiary care referral centre innorthern India. The clinical, imaging and histo-pathological features of patients with cystic schwan-nomas were studied.

Cystic schwannoma was defined as one wherecystic change involved more than 50% of tumour ongross examination. A total of 16 cases were found.Except demographic details, details of clinical andimaging features of four patients could not beretrieved. Haematoxylin and eosin stained sectionsof these cases were reviewed. Immunohistochemicalstains were studied wherever needed.

RESULTS

A total of 600 specimens of orbital tumours werereceived over a 16-year study period (1993–2008).Schwannoma accounted for 39 cases (6.5%). Ofthese, 16 were cystic schwannomas (41%). The ageranged from 20 to 65 years (mean age: 41 years). Theduration of symptoms varied from 3 months to15 years.

The presenting complaint was painless, progres-sive proptosis. One patient had a history ofrecurrence. The Snellen’s visual acuity ranged fromno perception of light to 6/6. Fundus findingsincluded disc oedema (6 cases), optic atrophy (1case), choroidal folds (3 cases) and macular oedema(2 cases). In three cases posterior segment was notvisible because of severe exposure keratopathy. CTscan showed well-defined lesions in all cases thatwere isodense or slightly hypodense when com-pared with brain. With contrast the tumours showedno or mild to moderate enhancement that was heter-ogenous in all cases. Cystic nature of tumour couldbe clearly identified in six cases. Bony changesincluded widened superior orbital fissure in onecase, herniation of the tumour into the maxillarysinus in one (Fig. 1a), erosion of the orbital roof intwo cases (Fig. 1b), fossa formation in the lacrimalgland area in two cases (Fig. 1c), and generalizedmassive expansion of the orbit with herniation of thetumour into the maxillary sinus and nasal cavity inone (Fig. 2a).

On ultrasound (USG) of the orbit, multiple cysticareas were detected in eight cases, whereas four werecompletely cystic. One of the cases that were purelycystic showed a double wall sign (Fig. 3).

The presumptive diagnosis was combinedvenous-lymphatic vascular malformation in 2, lacri-mal gland tumour in 2, dermoid cyst in 1, hydatidcyst in 2 and schwannoma in 5 cases.

a

b

c

Figure 1. (a) CT scan (coronal cut, bone window) showing awell-defined hypodense mass lesion in the inferior extraconalspace causing excavation of the orbital floor and herniation intothe maxillary sinus. (b) CT scan (sagittal cut) showing a well-defined hypodense mass lesion in superior extraconal spacecausing erosion of orbital roof and globe indentation. (c) CT scan(coronal cut) showing well-defined multicystic mass lesion inthe superolateral orbit causing fossa formation in the lacrimalgland area.

294 Kashyap et al.


On gross examination, the orbital masses mea-sured 1.0–3.5 cm in maximum dimension. Cutsurface revealed large and small cystic areas filledwith gelatinous material/straw coloured fluid(Fig. 4a).

On light microscopy, the cysts were of varyingsizes with no lining epithelium. The sparsely cellularareas or Antoni B areas were predominant in allthese cases and revealed large single or multiplecystic areas. The cellular areas or Antoni A areasconsisted of spindle shaped cells arranged in inter-lacing fascicles with typical verocay bodies (Fig. 4b).In addition, foamy macrophages with areas of haem-orrhage were identified in four cases. Calcificationwas seen in one case that presented with a recurrenttumour. Immunohistochemical staining was carried

out and was negative for cytokeratin and desmin,strongly positive for S-100 antibody (Fig. 4c) andweakly positive for vimentin, indicating that theselesions originated from schwann cells of the periph-eral nervous system.

DISCUSSION

Primary schwannoma of the orbit is a rare entity. Inour series it constituted to 6.5% of all orbitaltumours. Incidence reported in Western literature is1–5.7%.1,11 Large areas of cystic degeneration canoccur in schwannoma, but is an uncommon featureand so is rarely reported. On literature review oforbital schwannomas with cystic degeneration, wefound only 11 cases.7–13 Three of these were purelycystic7–9 and had a well-defined homogeneous non-enhancing mass on CT scan. Others were showingmultiple cystic spaces either on imaging orhistopathology.10–13 Single or multiple cystic changeson imaging is the most unusual presentation of aschwannoma and poses a diagnostic challenge to thetreating surgeon. The authors reporting the casesadvocate keeping schwannoma in the differentialdiagnosis of cystic lesions of orbit.

The clinical profile of our cases was similar to thatof the reported cases (Table 1). Five of 11 cases fromliterature review and 11 of 16 cases in our serieswere female. The age range of reported cases was18–84 years with 10 of 11 being 40 years or older.The age in our case series varied from 20 to 65 yearswith an average age of 41 years. An interestingobservation was that 9 of 11 reported cases and 6 (2involved both intraconal and extraconal spaces) of 12cases in our series were intraconal in location,whereas it is known that schwannomas most com-monly arise in the superior extraconal orbit.2 Theduration of symptoms was 2 months to 36 years inthe reported cases and 3 months to 15 years in ourseries with painless proptosis and vision loss as themajor complaint.

a bFigure 2. (a) CT scan (axial cut)showing a large orbital mass withmultiple large and small cystscausing massive generalizedexpansion of the orbit compromis-ing the nasal cavity. (b) MRI (axialcut) showing tumour isointensewith respect to muscle onT1-weighted image with multiplecystic spaces and a fluid level(arrow).

Figure 3. Paraocular ultrasound of the orbital mass lesionshowing single cystic lesion with a double wall sign (line arrowspointing the double walls, block arrow showing the globe).

Orbital schwannoma with cystic degeneration 295


Ultrasound features of schwannoma have beendescribed as a well-defined mass with variableinternal reflectivity. A-scan may demonstratemedium to high reflectivity suggestive of Antonitype A areas and low reflectivity areas suggestive ofAntoni type B pattern.13 In addition to these find-ings, cystic schwannomas usually show single largecystic area surrounded by few small cysts or rarelythe whole tumour is cystic.10–13 USG picks up cysticspaces clearly.13 In current series, USG was carriedout in all the cases as a routine investigation, whichshowed multiple cystic lesions in 8 cases and singlecyst in 4 cases. As USG defines the internal archi-tecture of a tumour clearly, it is advised in all casesof orbital tumours. One of the purely cystic schw-annomas showed a double wall sign that has beentypically described in orbital hydatid cyst.14 Thishas never been reported before in a case ofschwannoma.

On CT scan, schwannoma usually appears as awell-defined mass in the orbit, which is isodense orslightly hyperdense when compared with brain andtakes up contrast to variable degrees, that is, none tomoderate contrast uptake.2,15 A correlation betweenCT scan findings and histological structure of schw-annomas has been studied, where the authors foundthat the areas of Antoni A type of tissue were seen onCT in the form of hyperdense areas of the tumourwhereas Antoni B type of tissue had a markedhypodense picture.16 There may be widening of theorbital fissure or focal or general expansion of theorbit because of slowly progressive enlargement oftumour.2,10,17 A vast variety of bony changes wereseen in our cases, including bone erosion, superiororbital fissure widening, massive generalized orbitalexpansion, fossa formation and excavation of theorbital walls to the extent that the tumour herniatedinto the maxillary sinus and nasal cavity.

The diagnosis of schwannoma can only be madeon histopathology. Classically, the tumour showstwo distinct patterns of spindle cell arrangement: thesolid and cellular Antoni type A and the less cellularAntoni B pattern with myxoid areas. In addition,long-standing tumours may show degenerativechanges like cystic changes. Rarely areas of calcifica-tion may also be seen with in the tumour. Predomi-nance of the Antoni B pattern has been observed insoft and cystic schwannomas.1

To conclude, orbital schwannomas are great mas-queraders in the orbit, because of variable clinicaland imaging features. They may present as a singlecystic lesion or mass with multiple cystic lesions orwith a fluid level. USG should be carried out in allcases to pick up cystic spaces, a feature that may bemore common than reported. Furthermore, schwan-nomas should be kept in the differential diagnosis ofcystic mass lesion in the orbit. To the best of our

a

b

c

Figure 4. (a) Photograph of gross specimen showing a largecystic space in a well-encapsulated mass, filled with gelatinousmaterial. (b) Microphotograph showing a spindle cell lesion withnumerous cystic spaces devoid of lining epithelium. It revealsboth Antoni A areas (arrow) and Antoni B areas (haematoxylinand eosin stain, original magnification ¥40). Inset shows pallisad-ing spindle shaped cells (Verocay bodies) (haematoxylin andeosin stain, original magnification ¥400). (c) Spindle shaped cellsshowing immunohistochemical positivity for S-100 P stain (origi-nal magnification ¥100).

296 Kashyap et al.


Tab

le1.

Cas

esof

cyst

icsc

hwan

nom

asre

por

ted

inth

elit

erat

ure

(incl

udin

gth

ecu

rren

tse

ries

)

Aut

hor

(yea

r)C

ases

Age

(yea

rs)

Dur

atio

nof

sym

pto

ms

CT

scan

Ultr

asou

ndLo

catio

nSu

rger

y

Roo

tman

etal

.(1

982)

111

6036

year

sW

ell-d

efine

dm

ass

with

mild

unifo

rmco

ntra

stup

take

and

foca

lare

asof

calc

ifica

tion

Mai

nly

solid

with

few

cyst

icsp

aces

Intr

acon

alLa

tera

lorb

itoto

my

Konr

adan

dTh

iel

(198

4)12

184

Man

yye

ars

Hom

ogen

ous

wel

l-defi

ned

mas

sH

eter

ogen

ous

wel

l-d

efine

dm

ass

Sup

erol

ater

alex

trac

onal

–

Byr

neet

al.

(198

8)13

241

,66

5m

onth

sto

2ye

ars

Non

-enh

anci

ngw

ell-d

efine

dcy

stic

mas

sC

entr

alcy

stic

lesi

onsu

r-ro

und

edb

ysm

all

cyst

s

Intr

acon

alSu

per

ior

orb

itoto

my,

tran

s-fr

onta

lcra

niot

omy

Lam

etal

.(1

997)

71

545

year

sH

omog

enou

sno

n-en

hanc

ing

mas

ssu

gges

tive

ofcy

stic

natu

re–

Sup

erio

rex

trac

onal

Ant

erio

ror

bito

tom

yw

ithen

blo

cex

cisi

onTs

uzuk

iet

al.

(200

0)8

162

6m

onth

sSi

ngle

cyst

icm

ass

lesi

on–

Intr

acon

alM

icro

surg

ical

late

ralo

rbi-

toto

my

with

tota

lex

cisi

onTo

kuga

wa

etal

.91

646

mon

ths

Cys

ticm

ass

lesi

on–

Intr

acon

al–

Sub

ram

ania

net

al.

(200

5)10

418

–78

2m

onth

sto

5ye

ars

Wel

l-defi

ned

poo

rly

orno

n-en

hanc

ing,

isod

ense

orhy

pod

ense

mas

sw

ithcy

stic

spac

esin

one

case

and

bon

ere

mod

ellin

gin

one

case

Sep

tate

mas

sle

sion

with

low

mod

erat

ein

tern

alre

flect

ivity

inon

eca

se

Intr

acon

alO

rbito

tom

yw

ithto

tal

exci

sion

in3

and

enuc

leat

ion

with

tota

lex

cisi

onin

1

Cur

rent

seri

es(2

008)

1620

–65

3m

onth

sto

15ye

ars

Wel

l-defi

ned

poo

rly

orno

n-en

hanc

ing

isod

ense

orhy

pod

ense

mas

sw

ithflu

idle

vels

in1,

wid

enin

gof

sup

erio

ror

bita

lfiss

ure

in1,

eros

ion

ofor

bita

lroo

fin

2,he

rnia

tion

into

max

illar

ysi

nus

in2,

gene

raliz

edex

pan

sion

ofor

bit

in1

and

foss

afo

rmat

ion

inla

crim

algl

and

area

in2

case

s

Wel

l-enc

apsu

late

dm

ass

that

was

com

ple

tely

cyst

icin

4an

dha

dm

ultip

lecy

stic

area

sin

8ca

ses.

Dou

ble

wal

lsi

gnw

asse

enin

one

case

7ex

trac

onal

,4in

trac

onal

and

2b

oth

intr

acon

alan

dex

trac

onal

Orb

itoto

my

with

tota

lex

cisi

on(la

tera

lorb

ito-

tom

yin

6an

dan

teri

oror

bito

tom

yin

6ca

ses)

Orbital schwannoma with cystic degeneration 297


knowledge, this is the largest case series on cysticschwannoma reported in literature.

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orbital schwannoma with cystic degeneration

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