Pelvic retroperitoneal schwannoma presenting as a gynecologic mass: Case report

Pelvic retroperitonealschwannomapresentingas a

gynecologic mass:Casereport

r. Korkontzelosr,M.D.; E. Tsimoyiannis2,M.D.,ph.D.;a, zagalikit, M.D.;A. Demour, M.D.i E. Karabina', M.D.; N. Antonioal, M.D.,ph.D. IDepartment of obstetrics& Gynecology,2Department of Surgery,3Deparfinent aJpathology,. state GetteralHospitalof loannina " G. Chatzikosta',,Ioannina(Greece)

Summary Schwannomasof the sacral plexus are reroperitoneal^tumors,,usually benign, that result fiom proliferation of perineural cells. They are rare' pelvic, well definedtumors that presentinfrequently ginecollgr. as *urr.r. Misdiagnosisis not uncommon in these cases'since thesemassesare not often encounteredin clinical pracdc!"and preoperativeimaging methoclscan be only suggestive of the diagnosis.Furthermore,thesemassesare not often encountered in clinical practice.We report a caseof a 2g_year_old woman who presentedwith a pelvic mass and obscureclinical signs. Imaging ro.,ho.t, .ugg"sted thai this tumor was most probably an ovarian mass of embryonic origin. After di^ssectionby Japaitomy, tf,. ii..o."oprc examination showed tvprcal futures of a neurilemoma (ancient schwannoma).The goal of the operating intervention is to excise the tumor avoiding major trauma, thos tion between surgeonsis indispensabie.The patient has had no motor "ooperoor sensory clisturbancesafter surgery. Key words: Pelvic mass;Schwannoma;Diagnosis;Resecton.

Introduction Benign nerve sheath tumors are pseudoencapsulated tumors that arise from the neoplastictransformationof nerve sheathcells [1]. They are classifiedinto two maior categories,neurilemomasand neurofibromas.These neo_ plasms. associatedwith von Recklinghausen,sdisease (VRH) may originate at any anatomic site, but usually arise in the cranial nerves and occasionaliy in the nervei of the extremities [2]. Tumors of the sairal plexus are exceedinglyrare [31.We reporra caseof a piluic ,ass t h a t t u r n e d o u t t o b e a r e t r o p e r i t o n e a sl c h w a n n o m a (ancientschwannoma),not associatedrvith VRH.

benign cytology. The histological report of the excised tumor (Figure 3) described lesions that correspond to a degenerated schwannorna(ancient schrvannoma)with spindle cells ordered in bundlesand rare mitoses.Immunohisiochemicallythe tumor cells were strongly positive to vimentine (DACO l:40) and S_ 100 protein (DACO 1:1000) (Figure 4). The postoperarive course was uneventfui without neurologic or other deficits observed.

Discussion

Neuriiemomasare usuallv fbund incidentally and can occur with equal frequencyin malesand females,mostly betweenages 20-50 [2]. Peripheralnerve sheathtumor.s Case Report arising in the pelvic retroperitoneumpresentinfrequently A 2S-year-oid gynecologic masses.In particular, retroperitoneal as woman,gravidal, para 1, presented at our clinic with lowerpelvicpain,irregularmenses schwannomasoriginating frorn the sacral neties, like in ind frequenrun_ nation.The medicaihistorywasinsignificantwith no pasror our case, are exceedinglyrare [4]. Commoniy, these tamily history of VRH. The u,omandeniedany changesin massesremain asymptomaticattainjng a considerable bowelhabits.Gynecological examination revealedan immo_ size before being discovered.Even wlth larse tumors bile, solid,largemassoccupyingthe pelvisandexpandingto t h e y s t i l l r e m a i n a d i a g n o s t i cd i l e m m ab e c a i s eo f t h e therightside.The restof theclinicalandlaboratorv , exumroa_ tion was normal.Serumlevelsof cancerindexeswerealso non-specificsymptomsand findings. Diagnosis can be establishedoniy after histological within normalrange.Ultrasound sonography disclosed a mass approximately15 x 15 cm with cysticand soliclelements examination. Imaging methods can sometimesprovide additional information. CT findings usually presenr (Figure1). Pelvicradiography showedhydronephrosis of the right kidneyand displacement masses with a heterogeneous of the right ureier.Computecl pattern and areaso1 cystic tomography(CT) confrrmedthe existenceof a pelvic tumor degenerationand calcification.CT-guideclbiopsy may be with a sizeof 14 x 14 cm, suggesring rharit wasprobablyan helpful only if the samplecontainsenoughSchwanncells ovarianmassof embryonicorigin(Figure2). to visualizemicroscopically,but is still unreliablemisin_ After insertionof ureteralstents,the patientunderwentan terpretatingdegenerativecells as malignant[5]. Ogoseer exploratorylaparotomythatrevealednormaluterusandadnexes al. [6], reporteda casewhereneedleinsertioncausedpain anda retroperitoneal pelvicmass.Abdominalwashinsshowed along the sciatic nerve and supported that CT-gurded needle biopsy is worthwhile for making preoperative Revisedmanuscriptacceptedfor publicationAugust 10, 2004 diagnosesthough there is still risk of hemorrhaueor E u r .J C 1 n r e c .O n c u l . r : r : 0 j q 2 2 . )l o XXVI, n. 1,2005

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L Korkontzelos, E. T,sintoyiannis, A. Zagaliki, A. Demou, E. Karabina, N. Antoniott

Fi-e.1

Fig. i

trio 1

Fiq

Figure 1. Figure 2. Figure 3. Figure 4. -

flltrasound examinationshowing the pelvic mass with cystic and solid elements. Computed tomography showing the relation of the mass with other tissues. Macroscopicappearance. Microscopic appearance(S-100 protein, x 200).

infection.rJedaet al.. mentionedthat a cystic appearance is presentin approximately66Eoof the cases,helping in the differential diagnosisfiom other types of retroperitoneal tumors. [7]. However, neurilemomaswith totally cystic form have also beenreported [6]. T h e s e t u m o r s a r e u s u a l l y e n c a p s u l a t e da n d o f t e n appear wiih degenerativechangessuch as cyst fbrmation, calcificationand hyalinization.In particular,if they show degenerativechangesand degenerativenuclear atypia'in histologicalexamination,they are called ancientschwannomas. Retroperitoneal schwannomasare rare tumors difficult to diagnose14,61.The initial thinking was that this tumor was an ovarianmasswhile clinical symptomshad no diagnostic value. There was no radiating pain along the sciatic nerve and the report of irregular menseswas confusing. The same preoperativediagnosishas aiso been reported [4, 8]. Appropriate managementdepends on the age of the patient, the symptoms and the tumor's

location. White et al. l9l in a study of 57 patients r e p o r t e d i n c o m p l e t e r e s e c t i o ni n a b o u t l 0 7 o o f t h e cases. Dominqtrez et al. L10l mentioned a recurrence rate of 167c after a conservativeapproach,while Abernathy [1l, recommendedaggressiveresection due to high recurrencerate. Persistencealso seemsto be associated with the invoivementof pelvic bones. vessels, and majol pelvic nerves. However, the aim of surgical therapy is to excise the tumor avoiding nerve injury. If extensivedissectionis necessaryclear understandingof t h e a n a t o m y a n d c o o p e r a t i o n b e t w e e n s u r g e o n si s essentiai. Up to date, 20 cases of schwannomasof the pelvis have been reported I l]. Despite their rare occurrence they should be included in the differential diagnosis of gynecologic masses.Our patient has been followed for eight months after surgery and presentsasymptomatic, with no motor or sensorydisturbancesand no evidence of recurrent tumor.

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Pelvic retroperitoneal schwannoma presenting as a gynecologic mass: Case report

References [1] Abemathy C., Onofrio B., ScheithauerB., Pairoiero P.C., Shivis T.C.: "Surgical managementof giant sacrai schwannomas".J. Neurosurg., 1986, 65, 286. [2] Hunter V.P.,Burke T.W., Crooks L.: "Retroperitoneal nerve sheath tumors: An unusual case of back pain". Obstet. Gynecol., 7988, 71, 1050. [3] Whitaker WG., Droulias C.: "Benign encapsulatedneurilemoma: a report of 76 cases". Am. Surg., 1976, 42, 675. [4] Rajab K.E., Issa A.A., Skerman J.: "Unusual presentationof an abdominoinguinal schwannoma". Obstet. Gynecol., 2003,

102.rr58. [5] DaneshmandS., YoussefzadehD., Chamie K., Boswell W., Wu N., Stein J.P, et al.: "Benign reffoperitoneal schwannoma: a case series and review of the literature". Urology, 2003,62, 993. [6] Ogose A., Hotta T., Sato S., Takano R., Higuchi T.: "Presacral schwannoma with purely cystic form". Spine,2001, 26, 1817. 'A pelvic retroperitoneal schwan[7] Ueda M., Okamoto Y, Ueki M.: noma arising int the right paracolpium". Gynecol. Oncol, 1996, 60, 480.

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[ 8 ] K e n t o p p K . , J o n e sM . A . , D e C a i n M . , T a r c a z a H . M . : " P e l v i c retroperitoneal schwannoma mimicking an ovarian neoplasm: report of a case and review of the lilerature". Eur J. Gynecol. Oncol.. 1998, 19. 57. [9] White W., Shiu M.H., RosenblumM.K., Erlandson R.A., Woodruff J.M.: "Ceilular schwannoma.A clinicopathologic study of 57 patients and 5F tumors". Cancet 1990,66, 1266. [10] Dominguez J., Lobato R.D., Ramos A., Rivas J.J., Gomez PA., Castro S.: "Giant intrasacral schwannomas: report of six cases". Acta. Neurochir., 1997, I 39, 954. [11] Duran B., Guvenal T., Yildiz 8., Cetin M., Erden O., Demirkoprulu,N.: 'n'n unusual cause of adnexal mass: faliopian tube schwannoma". Gynecol. Oncol., 2004, 92, 343.

Address reprint requeststo: I.P. KORKONTZELOS, M.D. Department of Obstetrics and Gynecology State General Hospital of Ioannina "G. Chatzikosta" 4501 Ioannina (Greece)