TiiI"kisl1 NellI'Dslil"sery 11: 130 - 133, 2001 S~çkiii: Priiiinl"y EwiliS's ,nrcoiilfl of t1i~ miiiiiiiii

Primary Ewing's Sarcoma of the Cranium:Cas e Report

Kafatasinin Primer Ewing Sarkomu:Olgu Sunumu

HAKAN SEÇKiN, ALI VARAN, BEYHAN DEMiRHAN,DENiz ALTINOK, HAMiT ZAFER KARS

SSK Ankara Egitim Hastanesi, 2. Nörosirürji Klinigi, Ankara (HS, HZK),SSK Ankara Çocuk Hastanesi, Onkoloji Klinigi, Ankara (AV),

Baskent Üniversitesi Tip Fakültesi, Patoloji A.B.D., Ankara (BD),Ultramar Görüntüleme Merkezi, Ankara (DA)

Received : 7.5.2001 ç:, Accepted : 29.6.2001

Abstract: Primary Ewing's sarcoma of the cranium isquite uncomon. Pre or peroperative recognition of thisdisease is important as it leads planning the surgicalstrategy which effects the prognosis. We present a case ofprimary Ewing's sarcoma originating from mastoid boneand invading petrous bone, occipital bone, brain, dura,as well as tentorium, transverse sinus, skin and cervical

muscles. Radiological and pathological findings wered emons tra ted.

Key words: Cranium, Ewing's sarcoma, magneticresonance imaging, skull.

INTRODUCTION

Ewing's sareoma is a malignant primary bonetumor primarily seen in the long bones (4). PrimaryEwing's sareoma of the cranium is quite uneommonoeeuring in 1% of eases (2,3). We report on a ease ofprimary Ewing's sareoma that originated in themastoid bone. The tumor invaded the skull base, andalso extended to the eervieal region.

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Özet: Kranyumu tutan primer Ewing sarkomu nadirdir.Hastaligin ameliyat öncesinde veya ameliyat sirasindataninmasi cerrahi stratejinin planlanmasi ve prognozaçisindan önemlidir. Bu makalede mastoid kemikten

kaynaklanarak petröz ve oksipital kemikler ile beyin,dura, tentoryum, transvers sinüs, cilt ve boyun kaslarinitutan primer Ewing sarkomu olgusu sl1nulmu~tur.Radyolojik ve patolojik bulgular gösterilmistir.

Anahtar kelimeler: Kranyum, Ewing sarkomu, magnetikrezonans görüntüleme, kafatasi.

CASE REPORT

This 15-year-old girl presented with theeomplaint of a rapidly growing painful mass in theright retroaurieular area, as well as nuehal pain,nausea, and vomiting. Physieal examination revealeda firm, 5x5x3 em tender mass over the right mastoidbone. Neurologieal examination showed that thepatient was ataxie with an abnormal gait. She had

Tiirkisli Neiirosiirgery 11: 130 - 133, 2001

right-sided dysmetria, and nystagmus was observedon right lateral gaze. Magnetic resonance (MR)imaging revealed a right extraaxial soft tissue massinvolving the temporal and occipital bones. Thelesion was displacing the right cerebellar hemispheretowards the midline, and extended intracerebrallyin a transtentorial route. (Figure 1 a,b)

Digital subtraction angiography demonstratedanterior-superior displacement of the right middlecerebral arteries. There was no tumor staining onangiography. Right transverse sinus was notopacified secondary to the mass effeel. (Figure 2)

The patient was operated on and the tumor wassubtotalJy removed, leaving a smalJ remnantadherent to the torcular herophili that was infiltratingthe petrous bone. Profuse bleeding started when thetumor was detached from the right transverse sinus,and this was stopped by suturing the sinus next tothe torcular herophili.

The region of scalp that had been invadedby the tumor was also resected, along with alemmargin of normal skin. Plastic surgery helped duringthe closure of the scalp defect by a rotational skinflap.

Histopathological examination revealed that the

Figure la: A transverse T2-weighted MR image shows thehigh signal intensity of the extraaxial soft-tissuetumor, and reveals temporal and occipital boneinvolvement.

Seçkiii: Primnr!! Ell'iiis's SnrCOll1l1 ,'f Ilie ,miiiiiiii

tumor cells contained scant cytoplasm and theirnuclei were uniformly round or ovaL. The findingson periodic-acid-Schiff (PAS) staining was negatiye,as were immunochemical studies for leucocytecommon antigen (LCA), desmin, glial fibrillary acidieprotein (GFAP), CD 3 and CD 20. Some of the tumorcells stained pasitive for vimentin antibody. Basedon these results the pathological diagnosis wasEwing's sareoma (Figure 3).

Radiological and scintigraphic examinationsconfirmed that there were no other sites of

involvemenl. The patient was discharged with noneurological deficits for adjunctive radiotheraphyand chemotheraphy.

DISCUSSION

Ewing's sareoma is the second most commonbone tumor primarily seen in the long bones. Thisneoplasm is most frequently seen in children, with75 % arising in patients under 20 years. The male-ta­female ratio is 1.6:1. Ewing's sareoma is rarelyencountered in the skull, and only 1% of casesoriginate from the cranial bones.In documentedcases, the sites of origin have included the fronta!,parietal sphenoid and petrous bones (3).

Figure 1b: A post-contrast coranal Tl-weighted MR imagedemonstrates the enhancing extraaxial mass,which is praducing a significant mass effect inthe temporal and occipital lobes, and the rightcerebellar hemisphere.

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Tiirkisli Neiirosiirgery 11: 130 - 133, 2001

Figure 3:

Seçkiii: Priiiini·y Ewiiig's sareoiiia of tlie eral/ill/1/

A slide shows the tumor tissue composed ofuniform, small, raund cells with mild mitotic

activity ( H&E x 230).

Figure 2: The subtraction print of a right internal carotidarteriogram demonstrates highly abnormaleirculation with a large soft-tissue mass.

In published cases of primary Ewing's sareomaof the cranium, the most com mo n symptomsreported at the time of diagnosis have been localswelling and associated headache. Pôtients with theskull base as the primary site also showed proptosisand various types of cranial nerve palsy at initialpresentation (3,5,9).

The list of clinical and radiological differentialdiagnoses for primary Ewing's sareoma of thecranium includes osteosarcoma, lymphoma,meningioma, metastatic tumors, Langerhans' cellhistiocytosis and rhabdomyosarcoma (7,8).Biopsy isessential for definitiye diagnosis. The histologicaldiagnosis is made by examining the morphology,chromatin structure and immunohistochemical

profile of the tumor cells. This tumor is characterizedby small, uniform, densely packed cells with nodistinctive borders. Although cytoplasmic glycogencontent was considered to be important in differentialdiagnosis, in specimens fixed in formalin andembedded in paraffin, the glycogen could not bedemonstrated with PAS staining (6). In our case,positive immunohistochemical findings for vimentinand negative findings for desmin ruled outrhabdomyosarcoma, and negative results for ofLCA, CD 3 and CD 20 ruled out malignantlymphoma.

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Early diagnosis and treatment prior tometastasis is essential for long-term survival inpatients with Ewing's sareoma (3). The disease istreated through a multidisciplinary approach thatincludes surgery, chemotherapy, and radiotherapy.When the tumor affects the cranial bone, surgicalresection is particularly important. This has not onlybeen shown to improve survival, but als o may beneeded to decompress vital neural structures, as wastrue in our case (3). Surgical resection also has beenadvocated to decrease the primary tumor mass inpreparation for local radiation and chemotherapy(1,3).

Watanabe et aL.documented that the survival

rate is higher in cases of cranial Ewing' s sareoma thanin patients with this neoplasm at other sites (9).Desaiet. al reported high survival rates with the new erround cell chemotherapy (RCT)-1I protocol (3). Themain factor in treatment failure is the developmentof metastatic disease, the most common form beinglung metastasis (1).

In conclusion, it is important to considerEwing's sareoma of the cranium both pre- andintraoperatively because recognition of this conditionmay lead to total excision which is reported to be anessential aspect for prognosis.

Correspondence: Hakan Seçkin

Basak Sokak 61/16

Küçükesat 06660/ ANKARATel: 4465896 Fax: 4317462

Tiirkish Neiirosiirgery 11: 130 - 133, 2001

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The typical, but not diagnostic of Ewing's sareoma,

is the radiographic subperiosteal new bone formation

creating "onion-skin layering" in long bones.

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