Intracranial neoplasia is well described in the dog. 1,2

Transcription

1 J Vet Intern Med 2006;20: Cnine Intrrnil Primry Neoplsi: 173 Cses ( ) Jessi M. Snyder, Frnes S. Shofer, Thoms J. Vn Winkle, nd Christine Mssiotte This study investigtes the linil nd pthologi findings ssoited with 173 primry rin tumors in our hospitl popultion of dogs tht presented etween the yers 1986 nd Of the 173 primry rin tumors, 78 (45%) were meningioms, 29 (17%) were stroytoms, 25 (14%) were oligodendroglioms, 12 (7%) were horoid plexus tumors, nd 7 (4%) were primry entrl nervous system lymphoms. Smller numers of gliolstoms (n 5 5), primitive neuroetoderml tumors (n 5 5), histioyti sroms (n 5 5), vsulr hmrtoms (n 5 4), nd unlssified glioms (n 5 3) were identified. One dog hd oth meningiom nd n stroytom. Most tumors were loted within the telenephlon, nd seizures were the most ommon linil presenting omplint. Of 168 tumors for whih lotion in the rin ws reorded t postmortem exmintion, 79 were found to involve more thn 1 rin division. Other neoplsms unrelted to the primry rin tumor were identified on postmortem exmintion in 39 dogs (23%). Intrthori nd intrdominl neoplsms were present t neropsy in 13 nd 24 ses, respetively. Bsed on the results of this study, thori rdiogrphs nd dominl ultrsonogrphy my e indited to look for extrrnil neoplsi prior to dvned imging of the rin or intrrnil surgery. Key words: Brin tumor; Dignosis; Dog; Gliom; Meningiom. Intrrnil neoplsi is well desried in the dog. 1,2 The inidene of rin tumors in this speies my pproh 3.0%, lthough other uthors hve reported muh lower inidene of 14.5 per 100,000 dogs. 2,3 Older dogs my hve predisposition for primry rin tumors, nd reeds elieved to e t inresed risk of rin tumor inlude the Boxer, Golden Retriever, Doermn Pinsher, Sottish Terrier, nd Old English Sheepdog. 4 It hs een reported tht primry entrl nervous system tumors rising from mesoderml origin (meningioms) re the most ommon intrrnil tumors in dogs, followed y neuroetoderml (glil) tumors (stroytom nd oligodendrogliom). 5 Undifferentited sroms, horoid plexus tumors, medullolstoms, neurolstoms, nd ependymoms our less frequently. 5 Previous studies hve desried tumor types, linil signs, dignosis, nd outome ssoited with rin tumors in dogs. 4 8 These studies hve inluded metstti tumors nd those ffeting the rin y extension. To our knowledge, no lrge se series of primry intrrnil neoplsi in the dog hs een previously presented in the veterinry literture. The purpose of this study ws to desrie the linil nd pthologil findings in lrge group of dogs with primry intrrnil neoplsi nd to determine the prevlene of unrelted neoplsi in these dogs tht my omplite their dignosis nd tretment. From the Deprtment of Clinil Studies, Shool of Veterinry Mediine, University of Pennsylvni, Phildelphi, PA. Reprint requests: Jessi M. Snyder, Veterinry Speilty Center of Settle, th Avenue West, Lynnwood, WA 98036; e-mil: jessmik@yhoo.om. Reeived Deemer 7, 2004; Revised August 24, 2005; Aepted Septemer 16, Previously presented t the 22nd Annul ACVIM Sientifi Forum/Poster Presenttion, June Copyright E 2006 y the Amerin College of Veterinry Internl Mediine /06/ /$3.00/0 Mteril nd Methods The medil reord dtse t the Mtthew J. Ryn Veterinry Hospitl of the University of Pennsylvni (VHUP) ws serhed for dogs with dignosis of intrrnil neoplsi tht underwent postmortem exmintion etween 1986 nd Prmeters reviewed inluded signlment, linil history, neurologil exmintion findings, results of thori rdiogrphs nd ererospinl fluid (CSF) nlysis, nd results of mgneti resonne imging (MRI) nd omputed tomogrphy (CT). The lotion of the primry rin tumor, s well s other unrelted neoplsi identified on postmortem exmintion, were reorded. Metstti neoplsms involving the rin, tumors of the skull (eg, osteosrom, hondrosrom, multiloulr tumor of one), nd other neoplsms ffeting the rin y extension (eg, nsl, pituitry, nd rnil nerve tumors) were lso exluded from this study. Round ell neoplsms, suh s lymphosrom (LSA) nd histioyti srom (HS), were inluded if they were onfined to the entrl nervous system (CNS). If extrneurl round ell neoplsi ws deteted on postmortem exmintion, then these ses were exluded from nlysis. Bsed on these riteri, 173 rin tumors in 172 dogs were inluded, with 1 dog hving 2 histologilly distint primry rin tumors. The onset of linil symptoms relted to entrl nervous system disese, inluding seizure, vestiulr syndrome, nek pin, irling, lindness, menttion hnge, nisoori, nd regurgittion were reorded in eh se. On postmortem exmintion, tumor lotion within the rin, if provided, ws ssigned to 1 or more of 5 neurontomil divisions. These divisions inluded telenephlon, dienephlon, mesenephlon, nd/or metenephlon, myelenephlon, nd ereellum. If tumor ws noted to e loted in the olftory region, then this informtion ws lso reorded. The presene or sene of other neoplsi unrelted to the primry rin tumor ws reorded for eh se sed on the postmortem exmintion report. Unrelted neoplsi elsewhere in the ody ws reorded if the neoplsm ws hrterized s mlignnt in the postmortem report or if the tumor, lthough enign, ould use signifint linil signs of systemi illness (eg, drenl ortil denom nd pituitry denom). Benign derml, gstrointestinl, nd reprodutive neoplsms, suh s lipoms nd leiomyoms, were not inluded in this tegory. Ctegoril vriles were desried s proportions or perentges, nd omprisons etween them were performed using the hi-squred or Fisher s ext test, where pproprite. Normlly distriuted ontinuous vriles were desried using men 6 stndrd devition (SD), nd nonprmetri ontinuous vriles

2 670 Snyder et l Tle 1. Presenting linil omplints y tumor types in dogs with primry intrrnil neoplsi. Age t Presenttion Tumor Types (yers) Meningiom (rnge 4 15) Astroytom (rnge 4 15) Oligodendrogliom (rnge 2 14) Choroid plexus tumor (rnge 3 11) Lymphom (rnge 3 11) PNET (rnge 2 8) Gliolstom (rnge 2 11) Histioyti srom (rnge 4 11) Vsulr hmrtom (rnge ) Medin Time to Presenttion (dys) 30 (rnge 0 912) 21 (rnge 1 350) 14 (rnge 1 1,068) 51 (rnge 2 510) 28 (rnge 4 180) 28 (rnge 11 44) 21 (rnge 1 350) 31 dys (rnge 1 227) 1 dy (rnge 1 3) Numer of Cses Reported Seizure Vestiulr Syndrome Nek Pin d Vision- Loss e Menttion Chnge f Regurgittion PNET, primitive neuroetoderml tumor. Numer of ses for whih informtion on linil signs ws ville. Defined y 1 or more of the following linil signs: hed tilt, nystgmus, lening, tilting, or veering. d Either desried y the owner or eliited on spinl plption during the neurologil exmintion. e Defined s n sent mene response in 1 or oth eyes with intt rnil nerve 7 funtion nd no ovious ereellr disese. f Defined y 1 or more of the following: ehvior hnge, dementi, dullness, or disorienttion. were desried with medin nd rnge. The unpired t-test or Wiloxon rnk sum test ws used to ompre ontinuous vriles etween groups. For ll omprisons, P-vlue of,.05 ws onsidered signifint. All sttistil nlyses were performed using SAS sttistil softwre. Results Signlment Breeds inluded mixed reeds (n 5 56), Golden Retrievers (n 5 21), Boxers (n 5 18), Lrdor Retrievers (n 5 11), Germn Shepherd dogs (n 5 9), Bull Mstiffs (n 5 5), nd Rottweilers (n 5 5). Other reeds were less frequently represented. Compred with other reeds of dogs, Golden Retrievers nd Boxer dogs were t inresed risk to develop primry intrrnil tumors reltive to their frequeny in the generl hospitl popultion. All of the 4 Boston Terriers inluded in this study nd 16 of the 18 Boxers hd gliom identified on postmortem exmintion. Among dogs with stroytoms, 6/ 29 (21%) were Boxer dogs. Among dogs with oligodendroglioms, 9/25 (36%) were Boxer dogs. One of the 2 dogs with n undifferentited gliom ws Boxer. The men ge of ll dogs ws yers (rnge yers). The men ge y tumor type is presented in Tle 1. Dogs with meningioms were signifintly older thn dogs with other tumor types, nd for every yer inrese in ge, there ws 40% inresed risk of meningiom ompred with other primry rin tumors. There ws no sttistilly signifint differene etween the numer of femle dogs nd mle dogs in this study. Clinil History nd Neurologil Exmintion Findings The most ommon presenting neurologil signs were seizures (n 5 83), hnges in menttion (n 5 67), vestiulr syndrome (n 5 40), nd irling to one side (n 53). Other presenting neurologil signs were lindness (n 5 23), nek pin (n 5 20), nisoori (n 5 13), tremors of the hed nd/or lims (n 5 10), nd regurgittion (n 5 8). The most ommon linil signs y tumor type re presented in Tle 1. Dogs with oligodendroglioms were 3.6 times more likely to hve seizures ompred with dogs with other types of primry rin tumors (95% onfidene intervl on odds rtio ). Five meningioms nd 1 vsulr hmrtom were dignosed s inidentl findings on postmortem exmintion. The medin durtion of linil signs prior to dignosis for ll dogs ws 26 dys (rnge 0 1,068 dys), nd the medin durtion of linil signs prior to dignosis y tumor type is presented in Tle 1. Cererospinl Fluid Anlysis CSF ws olleted in 51 dogs with primry intrrnil neoplsi. The results re summrized in Tle 2. CSF in this study ws norml in 10% of ses, hrterized y n elevted ell ount in 58% of ses, nd hrterized y luminoytologi

3 Cnine Brin Tumors 671 Tle 2. Cererospinl fluid (CSF) nlysis results y tumor types in dogs with primry intrrnil neoplsi. Tumor type (Numer of Cses in whih CSF Anlyzed) Elevted Totl Protein Elevted White Blood Cell Count Norml CSF Anlysis (Numer of Cses) ACD Men Totl Protein (mg/dl) Men White Cell Count (ell/ul) Differentil Cytology Meningiom (16) Mixed ell pleoytosis, 4 e ; neutrophili, 3 f ; lymphoyti, 1 g ; lood ontmintion, 1 Oligodendrogliom (7) Mononuler pleoytosis, 1 h ; mixed ell, 1; eosinophili, 1 i ; lood ontmintion, 1 Astroytom (8) NA Mixed ell pleoytosis, 2; lood ontmintion, 1 Choroid plexus tumor (9) Mononuler pleoytosis, 4; mixed ell, 2 Lymphom (5) NA Mononuler ell typi, 1; mixed ell, 1; lymphoyti, 1; lympholsts, 1 PNET d (3) NA Mixed ell pleoytosis, 1; mononuler, 1 Histioyti srom Lymphoyti pleoytosis, 1 Gliolstom Mononuler pleoytosis, 1 Numer of ses with.25 mg/dl totl protein. Numer of ses with.5 ells/ul. Aluminoytologi dissoition; the numer of ses with.25 mg/dl totl protein nd,5 ells/ml. d Primitive neuroetoderml ell tumor. e Defined s greter.20% ontriution of 2 or more ell types (neutrophils, lymphoytes, nd mononuler ells). f Defined s ererospinl fluid with.75% neutrophils. g Defined s ererospinl fluid with.75% lymphoytes. h Defined s ererospinl fluid with.75% mononuler ells. i Defined s ererospinl fluid with.50% eosinophils. dissoition in 30% of ses. A mixed ell pleoytosis ws the most ommon ytologi normlity in the 51 smples. Cellulr typi or neoplsti ells were deteted in 2 of 6 dogs with CNS LSA in whih ytologi exmintion of the CSF ws performed. Rdiogrphi Exmintion The results of thori rdiogrphy were ville for 97/172 dogs (Tle 3). Anormlities were deteted in 18/97 dogs (19%). Anormlities deteted on thori rdiogrphy inluded presumptive metstti disese (n 5 8), pneumoni (n 5 5), megesophgus (n 5 3), megesophgus with spirtion pneumoni (n 5 1), nd presumptive rdi filure (n 5 1). Rdiogrphi interprettions of omputed tomogrphi imging were ville for 20 ses, nd for 18 of these 20 sns (90%), these imges orretly predited the presene of mss lesion in the rin. Of the 20 CT sns, 2 were interpreted s norml. Rdiogrphi interprettions of MRI were ville for 24 ses, nd the MRI results re summrized in Tle 4. Rdiogrphi interprettion orretly predited the presene of primry rin tumor in ll 24 ses for whih MRI of the rin ws performed (100%). In 17/24 ses (71%), rdiologists who reviewed the MRI sns of Tle 3. Results of thori rdiogrphs y tumor type in dogs with primry intrrnil neoplsi. Tumor Type (Numer of Cses in Whih Thori Rdiogrphy Performed) No Anormlities Deteted Metstti Disese Pneumoni Megesophgus Hert Filure Meningiom (45) Astroytom (9) Oligodendrogliom (18) Choroid plexus tumor (8) Lymphosrom (6) Gliolstom multiforme (3) Primitive neuroetoderml tumor (3) Histioyti srom (2) Vsulr hmrtom (2) Gliom

4 672 Snyder et l Tle 4. Mgneti resonne imging (MRI) findings in 24 dogs with primry intrrnil tumors. Tumor Type (No. of Cses) Meningiom (9) Choroid plexus tumor (3) Oligodendrogliom (5) Astroytom (3) Gliolstom Histioyti srom Intr- Versus Extrxil Mrgins T1WI T2WI Extrxil (8), likely intrxil Irregulr mrgins, well-defined mrgins (2), oth Intrxil Round with (2), well defined extr-xil mrgins Intrxil (5) Diffuse with indistint mrgins (2), distint mrgin Intrxil Ill-defined (2), regions, intrxil morphous nd extrxil Intr- nd extrxil Intrxil Multiloulted with ill-defined mrgins Multiloulted, distint orders Lymphom Intrxil Indistint to distint mrgins Hypointense Hyperintense (3), (4), isointense (3), to isointense Hyperintense with region, isointense hyperintense rim, mixed intensity, isointense Iso- to hyperintense nd (2) Hypointense Hyperintense (2), (4) isointense, with hyperintense enter Hypointense (3) Hyperintense (3) Postontrst Enhnement Strong (9), (4), homogenous (2) Strong nd homogenous (3) Strong, moderte, ring enhnement, mild fol rim, none Mild nd nonuniform (2), mild ring enhnement Isointense Hyperintense Strong nd Hypointense PNET Intrxil Ill defined Hypo to isointense Hyperintense entrlly with rim Trget pperne with rim nd enter strongly enhning Isointense Hyperintense Moderte strong nd pthy Hyperintense Moderte to strong nd Predition Aury, Other 8/9, Severe peritumorl edem (4), midline shift (7), involves riiform plte (2), ysti (2), erodes one, durl til 2/3, Ostrutive hydroephlus (2), severe peritumorl edem, mss effet 5/5 Assoited hemorrhge (3), ssoited yst, mss effet (2), peritumorl edem 1/3, 2/3 Mild peritumorl edem, mss effet ompressing or deviting ventrile (2) 0/1, 1/1 Brod sed nd pedunulted, mss effet 0/1, Extensive peritumorl edem, midline shift, possile hemosiderin surrounding mss 1/1 Mild midline shift, multifol (3 lesions) 0/1, 1/1 Edem, midline shift, involves nsl sinus nd frontl loe Indites the numer orretly predited y the rdiologist on the rdiogrphi report s the numer 1 differentil dignosis. Indites the numer orretly predited y the rdiologist on the rdiogrphi report s the numer 1 or numer 2 differentil dignosis. PNET, primitive neuroetoderml tumor. the primry intrrnil neoplsms orretly predited the histologi tumor type s their top differentil dignosis. Postmortem Exmintion Postmortem exmintion ws performed in 172/ 172 dogs. Primry intrrnil neoplsms dignosed on neropsy inluded meningioms (n 5 78), stroytoms (n 5 29), oligodendroglioms (n 5 25), horoid plexus tumors (n 5 12), LSA restrited to the CNS (n 5 7), gliolstoms (n 5 5), primitive neuroetoderml tumors (n 5 5), HS restrited to the CNS (n 5 5), vsulr hmrtoms (n 5 4), undifferentited glioms (n 5 2), nd mixed stroytom/ependymom (n 5 1). One dog hd oth n stroytom nd meningiom. The speifi lotion of the primry intrrnil neoplsm within the rin ws reorded in 168/173 ses. Most of the primry intrrnil neoplsms were loted in the telenephlon (n 5 106) nd, within this region, 28/106 were loted in the olftory re (26%). Lotion in the rin y tumor type is presented in Tle 5. Compred with other tumor types, stroytoms were 8 times more likely to involve the dienephlon (95% onfidene intervl ). There ws n 86% deresed likelihood tht meningioms would e loted in the dienephlon, ompred with other primry rin tumors (odds rtio ; 95% onfidene intervl

5 Cnine Brin Tumors 673 Tle 5. Tumor lotion within the rin in dogs with primry intrrnil neoplsi. Tumor Type (Numer of Cses) Olftory Are Telenephlon Dienephlon Mesenephlon/ Metenephlon Myelenephlon Cereellum Meningiom (76) Astroytom (29) Oligodendrogliom (25) Choroid plexus tumor (11) Lymphom (6) Histioyti srom (5) PNET (5) Gliolstom (4) Vsulr hmrtom (4) PNET, primitive neuroetoderml tumor ). Choroid plexus tumors were loted in the telenephlon in the mjority of ses. Four horoid plexus tumors involved oth the lterl nd third ventriles. Of the 29 stroytoms inluded in this study, 8 (28%) were loted in the ereellum. The presene or sene of other unrelted neoplsi ws reported in 170/172 dogs. Other neoplsi unrelted to the primry intrrnil tumor ourred in 38/170 dogs (23%). These results re presented in Tle 6. Of the 29 dogs with stroytoms, 9 (31%) hd nother neoplsm unrelted to the intrrnil tumor dignosed t postmortem exmintion. Of these 9 dogs, 2 hd orti ody tumors nd 1 hd hemodetom. Of the 77 dogs with meningioms, 21 (27%) hd other neoplsi unrelted to the meningiom identified on postmortem exmintion. Ten dogs with meningioms nd 1 dog with n stroytom hd 2 or more other types of unrelted neoplsi in ddition to their primry rin tumor. Twelve dogs in this study hd n drenl neoplsm dignosed t postmortem exmintion, nd 5 of these 12 dogs hd third type of neoplsi identified on neropsy in ddition to their drenl tumor nd their intrrnil tumor. In 1 dog, ruptured drenl ortil denom ws the presumed use of deth. Four dogs with meningioms hd hemngiosrom dignosed on postmortem exmintion. This tumor ws disseminted in 3 ses nd fol (onfined to the spleen) in 1 dog. No dog in this study hd Tle 6. Unrelted neoplsms identified on postmortem exmintion in 38 dogs with primry intrrnil neoplsms. Testiulr Primry Primry Other Intrrnil Pulmonry Tumor Type Neoplsi Neoplsi HSA Crdi d Adrenl e Thyroid f TCC g Neoplsi h Other Meningiom 4 i 5 4 i 1 i 8 3 i 1 1 Pnreti islet ell tumor, metstti primitive rinom, perinl rinom Astroytom Mmmry rinom, melnom Oligodendrogliom Gliolstom Choroid plexus tumor Vsulr hmrtom Mlignnt melnom Inludes pituitry denom in 4 ses nd nsl rinom in 1 se. One dog with meningiom hd simultneous stroytom. Inludes pulmonry rinom in 3 ses, ronhiolveolr rinom in 2 ses, nd nplsti srom of the lung in 1 se. Two dogs with meningiom nd pulmonry rinom lso hd drenl ortil denoms. Another dog with meningiom nd ronholveolr rinom hd n drenl denom. HSA, hemngiosrom. d Inludes orti ody tumor in 3 ses nd hemodetom in 1 se. e Inludes drenl ortil denom in 9 ses, drenl rinom in 1 se, nd pheohromoytom in 2 ses. f Inludes 1 thyroid rinom nd 2 thyroid denoms. g Trnsitionl ell rinom (TCC). One dog with meningiom nd TCC lso hd n drenl ortil denom. h Inludes seminom in 3 ses, interstitil ell tumor in 1 se, nd Sertoli ell tumor in 1 se. i One dog with meningiom nd HSA lso hd mlignnt orti ell ody tumor nd utneous mst ell tumor. Another dog with meningiom nd HSA lso hd pituitry denom. A 3rd dog with meningiom nd HSA lso hd myxosrom of the soft plte, nd 4th dog with meningiom nd HSA lso hd thyroid denom.

6 674 Snyder et l evidene on postmortem exmintion of extrrnil metstsis of the primry intrrnil tumor. Disussion This study hrterized primry intrrnil neoplsms in lrge group of dogs. Severl of the hrteristis were similr to previous reports, inluding the men ge of 9.5 yers for dogs in this study, nd seizures s the most ommon presenting linil omplint. 4 6 Anlysis of survivl time y tretment modlities nd y tumor types in this study ws not performed euse of the high rte of euthnsi immeditely following dignosis of the intrrnil mss. Postmortem exmintion ws n inlusion riteri in this study, whih my hve deresed the numer of dogs tht underwent dvned imging nd ggressive medil or surgil tretments. Conlusions drwn on severl groups, inluding LSA, HS, PNET, nd vsulr hmrtom, must lso e interpreted with ution euse of their smll popultion size. Dogs with meningioms were signifintly older thn dogs with other tumor types. However, there ws no sttistilly signifint differene in the ge t presenttion mong dogs with other tumor types. Meningioms nd vsulr hmrtoms were the only primry intrrnil tumor types to e disovered on postmortem exmintion s n inidentl finding. Meningioms re slow-growing tumors tht my e present, espeilly in the rostrl ererum, for prolonged period of time efore linil signs of intrrnil disese eome ovious to the owner. 8,9 Further, owners my ttriute more sutle signs of forerin disese (suh s ping or menttion hnge) to the norml ging proess in geritri pet. 10 Inidentl tumors in this study omprised 3.4% of ll tumors, whih is lower thn the rte of inidentl tumors in ts (18.8%) reported in reent study. 11 Compred with ts, multiple meningioms in dogs re less ommon nd ourred in only 1 dog in this study. 5,11 Bsed on the results of this study, Golden Retrievers nd Boxer dogs re t inresed risk for intrrnil neoplsi. This finding is onsistent with previous reports. 4,6 Boxers nd other rhyephli reeds hve een previously reported to e espeilly prone to glioms. 5,12,13 In our study, Boxers nd Boston Terriers were more likely to hve n stroytom, oligodendrogliom, or undifferentited gliom dignosed on postmortem exmintion thn nother type of primry intrrnil neoplsm. Other uthors hve suggested tht rhyephli reeds re lso prone to gliolstom, ut this did not pper to e the se in our study. 2,5 In previous report of 5 dogs with gliolstom, only 1 ws rhyephli reed. 14 In our study, the 2 most ommon presenting linil omplints were seizures nd menttion hnges, nd most tumors were loted in the telenephlon. Of the tumors loted in the udl foss, stroytoms were loted in the ereellum in lmost one third of ses. It hs previously een reported tht stroytoms our rrely in the ereellum. 2,7,15 Choroid plexus tumors in this study were loted in the lterl ventriles in the mjority of ses, rther thn in the 3rd or 4th ventriles, whih lso differs from other reports. 2,16 Severl of the horoid plexus tumors ffeted oth the lterl nd the third ventriles. Hlf of the intrrnil neoplsms in our study oupied more thn 1 ntomi region of the rin. This is importnt euse these tumors my e ssoited with neurologil normlities tht suggest multifol disese. Of the primry intrrnil neoplsms in this study, lmost one fifth were loted in the olftory re. This is region tht n e ssoited with norml neurologil exmintion despite the presene of spe-oupying mss. 8 It is lso n re tht is essile for iopsy nd surgil removl CSF findings in this study re onsistent with previous reports, whih suggest tht inflmmtory hnges re more ommon thn luminoytologi dissoition in ses of intrrnil neoplsi. 8,20 Previous reports desrie neutrophili pleoytosis ssoited with CSF olleted from nimls with meningioms. 10,20 22 In our study, neutrophili pleoytosis ws seen only in CSF olleted from ses of meningioms. However, the most ommon ytologi normlity in the primry intrrnil neoplsms in our study ws mixed ell pleoytosis. Previous reports suggest tht horoid plexus tumors re ssoited with the most mrked elevtions in CSF totl protein, nd our study supported this finding. 20,21 In this study, CT imging proved to e less urte for detetion of n intrrnil mss thn MRI. This grees with previous reports in dogs nd in humns Chrteristis of the primry intrrnil neoplsms on MRI nd the ury of the reviewers in prediting histologi tumor types ws generlly onsistent with previous reports of meningiom, horoid plexus tumor, oligodendrogliom, nd stroytom. 23,26 In our study, the MRI reviewers inorretly identified 2 stroytoms, 1 gliolstom, nd 1 HS, mong others. MRI findings hve een desried in 5 dogs with gliolstom multiforme, nd the tumor imged in this study differed slightly from those in the previous report in hving irregulr mrgins nd pedunulted shpe. 14 The results of previous reports on MRI findings in ses of stroytoms suggest tht these tumors lk overll onsisteny in their MRI pperne. 15,23,26 HS is less ommon primry intrrnil neoplsm, nd its intrxil lotion my led to n erroneous dignosis of gliom. Further, dogs with gliolstom, HS, nd stroytom my hve tumors hrterized on MRI y morphous oundries, whih my mimi infetious or inflmmtory disese. Thori rdiogrphs were norml in 18.5% of dogs in this study. The most frequent normlities deteted on thori rdiogrphs were metstses of unrelted extrrnil neoplsms. Other diseses, suh s megesophgus, pneumoni, or rdi filure, were present in the remining dogs, lthough less ommon. This finding is of prime importne euse metstti disese lerly worsens the prognosis for long-term

7 Cnine Brin Tumors 675 survivl following tretment of intrrnil msses. Further, nerly one qurter of the dogs in this study hd n unrelted, ut potentilly linilly signifint, form of neoplsi identified on postmortem exmintion, nd 6% of the dogs hd 2 or more different types of unrelted neoplsi identified on postmortem exmintion. This indites the need to perform sreening tests, suh s thori rdiogrphy, nd possily dominl ultrsonogrphy, prior to performing invsive nd expensive nillry dignostis or therpeuti proedures in dogs suspeted to hve rin tumor. Conlusion Bsed on the results of our study, primry intrrnil neoplsms re ommon in older dogs of mny reeds. The tumors oupy more thn 1 ntomi division of the rin in mny ses, whih my use neurologil normlities suggesting multifol disese. CSF nlysis, in the se of lymphosrom, my e helpful in hieving dignosis. However, euse of the inflmmtory nture of CSF seen with primry intrrnil neoplsi, this test my not e helpful in differentiting etween neoplsti nd other inflmmtory diseses. Finlly, thori rdiogrphy nd potentilly dominl ultrsonogrphy should e pursued prior to performing dvned dignostis nd therpeutis given the high rte of unrelted neoplsi in dogs with primry intrrnil neoplsms. Footnotes Version 8.2, SAS Institute, Cry, NC Referenes 1. Luginuhl H, Frnkhuser R, MGrth JT. Spontneous neoplsms of the entrl nervous system in nimls. Prog Neurol Surg 1968;9: Zki FA. Spontneous entrl nervous system tumors in the dog. Vet Clin N Am Smll Anim Prt 1977;7: Vndevelde M. Brin tumors in domesti nimls: An overview. Proeedings, Conferene on Brin Tumors in Mn nd Animls, Reserh Tringle Prk, NC; Heidner GL, Kornegy JN, Pge RL, et l. Anlysis of survivl in retrospetive study of 86 dogs with rin tumors. J Vet Intern Med 1991;5: Nfe LA. The linil presenttion nd dignosis of intrrnil neoplsi. Sem Vet Med Surg 1990;5: Bgley RS, Gvin PR, Moore MP, et l. Clinil signs ssoited with rin tumors in dogs: 97 ses ( ). J Am Vet Med Asso 1999;215: Turrel JM, Fike JR, LeCouteur RA, et l. Computed tomogrphi hrteristis of primry rin tumors in 50 dogs. J Am Vet Med Asso 1986;188: Foster ES, Crillo JM, Ptnik AK. Clinil signs of tumors ffeting the rostrl ererum in 43 dogs. J Vet Intern Med 1988; 2: de LHunt A. Veterinry Neurontomy nd Clinil Neurology, 2nd ed. Phildelphi, PA: WB Sunders; 1983: LeCouteur RA. Brin tumors of dogs nd ts. Vet Med Rep 1990;2: Troxel MT, Vite CH, Vn Winkle TJ, et l. Feline intrrnil neoplsi: Retrospetive review of 160 ses ( ). J Vet Intern Med 2003;17: LeCouteur RA. Current onepts in the dignosis nd tretment of rin tumours in dogs nd ts. J Smll Anim Prt 1999;40: LeCouteur RA. Tumors of the Nervous System. In: Withrow SJ, MEwen EG, eds. Smll Animl Clinil Onology. Phildelphi, PA: WB Sunders; 2001: Lipsitz D, Higgins RJ, Kortz GD, et l. Gliolstom multiforme: Clinil findings, mgneti resonne imging, nd pthology in five dogs. Vet Pthol 2003;40: Frenier SL, Krft SL, Moore MP, Gvin PR. Cnine intrrnil stroytoms nd omprison with the humn ounterprt. Compend Contin Edu Prt Vet 1990;12: Moore MP, Bgley RS, Hrrington ML, et l. Intrrnil tumors. Vet Clin N Am Smll Anim Prt 1996;26: Kolik PD, LeCouteur RA, Higgins RJ, et l. Modifition nd pplition of Pelorus Mrk III stereotti system for CT-guided rin iopsy in 50 dogs. Vet Rdiol Ultrsound 1999;40: Glss EN, Kptkin A, Vite C, Steinerg SA. A modified ilterl trnsfrontl sinus pproh to the nine frontl loe nd olftory ul: Surgil tehnique nd five ses. J Am Anim Hosp Asso 2000;36: Kostolih M, Dulish ML. A surgil pproh to the nine olftory ul for meningiom removl. Vet Surg 1987; 16: Biley CS, Higgins RJ. Chrteristis of isternl ererospinl fluid ssoited with primry rin tumors in the dog: A retrospetive study. J Am Vet Med Asso 1986;188: Biley CS, Vernu W. Cererospinl fluid. In: Kneko JJ, Hrvey JW, Bruss ML, eds. Clinil Biohemistry of Domesti Animls, 5th ed. Sn Diego, CA: Ademi Press; 1997: Crrillo JM, Srfty D, Greenlee P. Intrrnil neoplsm nd ssoited inflmmtory response from the entrl nervous system. J Am Anim Hosp Asso 1986;22: Thoms WB, Wheeler JS, Krmer R, et l. Mgneti resonne imging fetures of primry rin tumors in dogs. Vet Rdiol Ultrsound 1996;37: Brnt-Zwdzki M, Bdmi JP, Mills CM, et l. Primry intrrnil tumor imging; omprison of mgneti resonne imging nd CT. Rdiology 1984;150: Gvin PR, Fike JR, Hoopes PJ. Centrl nervous system tumors. Semin Vet Med Surg (Smll Anim) 1995;10: Krft SL, Gvin PR, DeHn C, et l. Retrospetive review of 50 nine intrrnil tumors evluted y mgneti resonne imging. J Vet Intern Med 1997;11: