Pesq. Vet. Bras. 38(10):1989-1998, outubro 2018 DOI: 10.1590/1678-5150-PVB-5925 Original Article Pequenos Animais/Small Animals Diseases ISSN 0100-736X (Print) ISSN 1678-5150 (Online)
PVB-5925 SA Pathological features of 78 metastatic or multicentric neoplasms involving the central nervous system in dogs1 Lilian C. Heck2, Fernanda G. Cony2, Matheus V. Bianchi2, David Driemeier2, Luciana Sonne2 and Saulo P. Pavarini2*
ABSTRACT.- Heck L.C., Cony F.G., Bianchi M.V., Driemeier D., Sonne L. & Pavarini S.P. 2018. Pathological features of 78 metastatic or multicentric neoplasms involving the central nervous system in dogs. Pesquisa Veterinária Brasileira 38(10)1989-1998. Setor de Patologia Veterinária, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9090, Porto Alegre, RS 91540-000, Brazil. E-mail: [email protected] Pathological features of 78 metastatic or Secondary neoplasms affecting the central nervous system (CNS) may occur through multicentric neoplasms involving the central nervous system in dogs1 blood flow or direct extension. This condition occurrence has increased both due to a longer life expectancy of dogs, as well as with the employment of chemotherapeutics, which may [Aspectos patológicos e distribuição de 78 neoplasias increase the survival period and, thus, the odds of the occurrence of metastasis. The aim neoplasms involving the CNS of 78 dogs, and, based on the data, estimate the occurrence metastáticas ou multicêntricas envolvendo o sistema of this study was to analyze the epidemiological features, such as the age, breed and sex of nervoso central de caninos.]. the animals affected, as well as the gross and microscopic findings of the metastasis from
Heck L.C., Cony F.G., Bianchi M.V., Driemeier D., Sonne L. and frequency of the metastatic or multicentric neoplasms. Females (71.79%) were most & Pavarini S.P. 1989- affected than males, with an average age of 9.5-years-old and a median of 10-years-old. Most 1998 of the cases had a multifocal distribution (73.07%), and epithelial neoplasms (50%) were the(19.23%), most common. lymphoma Telencephalon (10.26%) and was melanoma the most (6.41%). affected Less neuroanatomical common neoplasms region (61.1%).included Mammary neoplasms were the most frequent (47.44%), followed by hemangiosarcoma
osteosarcoma, histiocytic sarcoma and lung carcinoma (2.56%). Mammary neoplasms were mainly composed of anaplastic and micropapillary carcinomas, of which only multifocal microscopic lesions were observed. neuropathology, secondary neoplasms, mammary carcinoma, hemangiosarcoma, pathology. INDEX TERMS: Metastasis, multicentric neoplasms, central nervous system, dogs, brain tumors,
RESUMO.- [Aspectos patológicos e distribuição de afetados, bem como caracterizar os achados macroscópicos 78 neoplasias metastáticas ou multicêntricas envolvendo e microscópicos de neoplasmas com metástases envolvendo o sistema nervoso central de caninos.] Neoplasias o SNC de 78 caninos e, baseado nestes dados, estimar a secundárias envolvendo o sistema nervoso central (SNC) ocorrência e a frequência de neoplasias metastáticas ou podem ocorrer por via hematógena ou por extensão direta. multicêntricas. Fêmeas (71,79%) foram mais afetadas do A ocorrência desta condição vem aumentando devido à que machos, com uma idade média de 9,5 anos e mediana de expectativa de vida mais longa dos cães, bem como através 10 anos. A maior parte dos casos apresentava distribuição do uso de quimioterápicos, os quais podem ampliar a multifocal (73,07%), e neoplasias de origem epitelial (50%) sobrevida e, portanto, as chances para a ocorrência de foram as mais frequentes. A localização neuroanatômica metástases. O objetivo deste estudo foi analisar os aspectos epidemiológicos, como idade, raça e sexo dos animais mais afetada foi o telencéfalo (61,1%). As neoplasias mamárias foram as mais frequentes (47,44%), seguidas por 1 Received on May 24, 2018. hemangiossarcoma (19,23%), linfoma (10,26%) e melanoma Accepted for publication on June 1, 2018. (6,41%). Osteossarcoma, sarcoma histiocítico e carcinoma 2 Setor de Patologia Veterinária, Faculdade de Veterinária, Universidade pulmonar (2,56%) foram neoplasias menos frequentes. Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 9090, Agronomia, Porto Alegre, RS 91540-000, Brazil. *Corresponding author: Os tipos de neoplasmas mamários mais observados foram [email protected] o carcinoma anaplásico e o carcinoma micropapilar, nesses
1989 1990 Lilian C. Heck et al. dois tipos as lesões eram multifocais e observadas somente na microscopia. tissues were cut at 3µm thickness, placed on histological slides and diencephalon,stained by hematoxylin mesencephalon, and eosin rhombencephalon, (HE). The location corpusof the neoplasms striatum, nervoso central, caninos, tumores encefálicos, neuropatologia, neoplasias was classified in seven neoplastic cell distributions: telencephalon, TERMOS DE INDEXAÇÃO: Metástase, neoplasias multicêntricas, sistema secundárias, carcinoma de glândula mamária, hemangiossarcoma, divided in three patterns according to the neoplastic cells distribution: patologia. meningeal,cerebellum intravascularand spinal cord. and Microscopically, nodular. Frequency the neoplasmsand distribution were
INTRODUCTION the breeds, age ranges (minimum, maximum and mean) and sex of animalsof metastatic affected. neoplasms involving the CNS were defined, as well as Metastatic or secondary neoplasms of the central nervous RESULTS system(Higgins (CNS) et al. are2017). defined Yet, asthese intracranial neoplasms or mayintramedullary also occur neoplasms,by local or direct which extension disseminate to the mainly CNS, ashematogenously in nasal cavity carcinomas and facial/vertebral osteosarcomas (Cantile & During the period analyzed, 4,643 dogs were necropsied, amongmetastases which from 883 distant had extra-neural primary sites malignant involving neoplasms the CNS, the CNS has increased in dogs, and it may be related to a ascorresponding the cause of to death. 1.67% Of of these, the causes 78 (8.83%) of death cases in the showed period Yousseflonger life 2016). expectancy The occurrence of these animals, of metastatic since thisneoplasms condition to primary neoplasms accounted for 42.23% (total of 55 cases). and to 57.77% of the neoplasms involving the CNS, while occursrange (Higgins mostly etin al.dogs 2017). older Furthermore, than nine-years-old, the employment while mesenchymal in 28 (35.89%), and in the remaining 11 cases primaryof chemotherapeutics neoplasms are asobserved a treatment in dogs to withneoplasms a broad may age Neoplasms were from epithelial origin in 39 cases (50%), increase the survival time of dogs, and, consequently, it may expand the odds of the establishment of a metastasis in the (14.11%) were mixed origin tumors. The mean age of the CNS (Fenner 1990). affected thandogs males was of (28.2%, 9.55-years-old n=22). (age range of two to Metastasis involving the CNS can be diagnosed through the 17-years-old). Females (71.79%, n=56) were most often association of the gross, microscopic and immunohistochemistry lymphoma,Mammary melanoma, neoplasms osteosarcoma, were the most histiocyticfrequent metastatic sarcoma neoplasmsand lung carcinoma. observed, Other followed less frequent by hemangiosarcoma, neoplasms occurred findings,in the primary which neoplasm allow defining site (Higgins the origin et al. of 2017). the metastatic Unequal neoplasticresults have cells been through reported a comparison in previous withstudies the regarding cells present the relative and absolute frequencies of metastatic neoplasms individuallyinvolving the and CNS accounted are illustrated for seven in cases.. Total number, neoplasms being more common in one study (Song et al. 2013) frequencyand secondary of intracranial neoplasms neoplasms in another in (Snyder dogs, with et al. primary 2008). multifocally in the CNS (more thanTable one 1neuroanatomical In 57 cases (73.07%), the lesions were distributed frequency, age and breed predilection of these neoplasms However, the knowledge about the origin, distribution, region), while in 21 cases (26.93%) the neoplasm was focal. the occurrence and estimate the frequency of metastatic or The(26.9%, most n=21) common and affected diencephalon neuroanatomical (24.3%, n=19). site was Other the ismulticentric rare (Snyder neoplasms et al. 2008). involving This thestudy CNS aims in dogs to determinesubmitted telencephalon (64.1%, n=50), followed by the cerebellum for necropsy from January 2006 to December 2016, and to describe the lesions distribution and to classify the dogs Table 1. Absolute, relative frequency and total number of according to the age group, sex and breed. metastatic CNS neoplasms Absolute Relative Metastasis MATERIALS AND METHODS frequency frequency Mammary Tumorneoplasms 37 47.44 Total231 16.02 Hemangiosarcoma 15 19.23 97 15.46 The database of the reports from necropsies performed in a veterinary Lymphoma 8 10.26 73 10.96 pathology laboratory between January 2006 and December 2016 Melanoma 5 6.41 39 12.82 were reviewed in search for cases of dogs in which the cause of death from the CNS. Among these metastatic neoplasms, the ones that Osteosarcoma 2 2.56 69 2.90 was related to metastatic neoplasms, excluding those originated Histiocytic sarcoma 2 2.56 12 16.67 Lung carcinoma 2 2.56 17 11.76 cellsinvolved in the the CNS CNS similar were to selected. the ones The observed primary in distantcriterion sites for (primary defining these neoplasms as metastatic was the observation of neoplastic Nasal cavity carcinoma 1 1.28 21 4.76 Cholangiocarcinoma 1 1.28 33 3.03 involved other tissues outside the CNS. Metastasis by direct extension location), while lymphomas were defined as multicentric when it 1 1.28 17 5.88 Synovial sarcoma 1 1.28 2 50.00 Thyroid carcinoma was excluded from this study, and, thus, only neoplasms with distant Apocrine gland carcinoma 1 1.28 1 100.00 origin from the CNS were selected. Data regarding the age, sex, breed Malignant peripheral nerve 1 1.28 10 10.00 and origin of the neoplasms were grouped and registered. Primary sheath tumor CNS neoplasms were also reviewed for comparison. Pheochromocytoma 1 1.28 15 6.67 After cases were selected, the histological slides and formalin-fixed paraffin-embedded tissues were collected. The paraffin-embedded Pesq. Vet. Bras. 38(10):1989-1998, outubro 2018 Pathological features of 78 metastatic or multicentric neoplasms involving the central nervous system in dogs 1991
Fig. 1A) to neuroanatomical regions were less commonly affected. Gross lesions in the CNSFig.1B were and observed 1C) and, occasionally,in 18 dogs, CockerMixed‑breed (6.41%) dogs and were Boxer the (5.13%, most affected n=4). (37.18%, n=29), which were characterized by focal (11 cases) ( followed by Rottweiler (15.38%, n=12), Poodle (8.97%, n=7), cerebellummultifocal (7 (n=5), cases) diencephalonwhite ( (n=3), corpus striatum Mammary neoplasms (n=2),red nodules. mesencephalon These cases (n=2) involved and therhombencephalon telencephalon (n=16), (n=1). Metastasis to the CNS of mammary neoplasms accounted lesions (Figure 1D Figure 1E The remaining cases (19/37) did not present any CNS gross for 37 cases, of which mixed-breed dogs were the most these cases consisted show of 10multifocal anaplastic neoplastic carcinomas cells and inside blood affected (n=10), followed by Cocker (n=4), Poodle (n=4) vesselsshow 9 and,micropapillary occasionally, invasive extending carcinomas). to the neuropil, The lesion forming in affectedand Rottweiler (36 cases). (n=4). The mean age was of 10.5-years-old micrometastases (n=14) or involving the leptomeninges (n=6) (age range of five to 17-years-old), and females were mostly
Fig.1. Mammary metastatic neoplasms in the central nervous system of dogs. (A telencephalon. (B C) Comedocarcinomas ) Solid carcinoma. Focal whitish to reddish Dnodule) Anaplastic in the ) Comedocarcinoma. Multifocal whitish nodules involving the telencephalonE and cerebellum. ( arrangedwere characterized in micrometastasis. by multiple HE, nodular obj.20x. structures (F) Anaplastic of neoplastic carcinomas cells alsocontaining involved a central the leptomeningeal area of necrosis. spaces. HE, obj.40x.HE, obj.20x. ( carcinomas were highly pleomorphic and arranged in micrometastases. HE, obj.20x. ( ) Micropapillary invasive carcinomas were also
Pesq. Vet. Bras. 38(10):1989-1998, outubro 2018 1992 Lilian C. Heck et al.
(Fig.1F micropapillary). The mammary invasive carcinoma neoplasms (n=9), with comedocarcinoma metastasis to the most affected (n=2), and the mean age was of 5.8-years-old CNS(n=6), were solid classified carcinoma in (n=3),types: carcinosarcomaanaplastic carcinoma (n=3), (n=10), simple (age range of two to 10-years-old). Male dogs were mostly tubulopapillary carcinoma (n=3), adenosquamous carcinoma leptomeningesaffected (6 cases). of the The brain neoplasm (n=7) ( Fig.3Awas observed) and sometimes only by (n=2) and mixed carcinoma (n=1). involvedmicroscopic the analysisneuropil in blood seven vessels cases, (n=4) of which (Fig.3B it affected). One dogthe presented a focal metastasis in the spinal cord (thoracic Hemangiosarcoma the dura-mater externally (extradural). segment), characterized by a grayish soft mass which involved A total of 15 cases of hemangiosarcomas with metastasis to Melanoma the CNS were accounted. Mixed-breed (n=9) and Rottweilers (n=2) were the most affected. The mean age was 9.7-years-old (agenodular range (2.5cm of seven in diameter) to 13-years-old). areas involving Eight dogs the telencephalon were females Metastatic melanomas in the CNS were observed in five and(n=15), seven diencephalon were males. All (n=11), cases had cerebellum multifocal (n=10), red pinpoint corpus to dogs. Mixed-breed dogs (n=3) were the most affected, followed striatum (n=7), rhombencephalon (n=5) and mesencephalon (n=3) (Fig.2A and 2B). Microscopically, these metastases in by Rottweiler and Dobermann breeds. The mean age was of 10.5-years-old (age range of nine to 12-years-old). Two of forming vascular irregular structures frequently distended by theseGrossly, dogs wereall cases females had focal and three(1 case) males. to multifocal These neoplasms (4 cases) the CNS were characterized by endothelial neoplasticFig.2C and cells2D). were originated from the digits (n=2) and oralFig.3C mucosa (n=3).
Lymphomablood and with adjacent hemorrhagic areas ( black, occasionally white, well-defined nodules ( ). The most Lymphomas involving the CNS represented eight cases, andaffected mesencephalon neuroanatomical (n=1). location Histologically, was the telencephalon the neoplastic (n=5), cells followed by corpus striatum (n=1), rhombencephalon (n=1) granules in the cytoplasm, and high mitotic index (Fig.3D). of which multiple organs were affected, and, thus, there varied from round to spindle, with variable amount of melanin was a multicentric condition. Mixed-breed dogs were the
Fig.2. Metastatic hemangiosarcoma in the central nervous system of dogs. (A) Multifocal reddish pinpoint to nodular areas in the telencephalon. (B also involved the mesencephalon. (C D) ) Sagittal cut surface of the cerebellum and cerebrum showed multifocal pinpoint to nodular reddish areas, which ) The neoplastic cells were frequently obscured by severe hemorrhagic areas. HE, obj.40x. ( The metastatic endothelial neoplastic cells were arranged in multiple irregular vascular structures, distended by blood. HE, obj.20x. Pesq. Vet. Bras. 38(10):1989-1998, outubro 2018 Pathological features of 78 metastatic or multicentric neoplasms involving the central nervous system in dogs 1993
Fig.3. Multicentric lymphoma, metastatic melanoma and osteosarcoma in the central nervous system of dogs. (A) Neoplastic lymphocytes in the leptomeninges. HE, obj.40x. (B obj.20x. (C D) Neoplastic ) Neoplastic lymphocytes in the leptomeninges with envolvement of neuropil blood vessels. HE, (E,F ) Metastatic melanomas were characterized by multifocal black to whitish nodules in the telencephalon. ( melanocytes were round to spindle and arranged in mantles, with variable amounts of melanin granules in the cytoplasm. HE, obj.20x. ) Metastatic osteosarcoma occurred in both cases as focal white nodules in the dorsal part of the cerebellum. Osteosarcoma Histiocytic sarcoma
Two dogs had metastasis of osteosarcoma in the CNS. One of Two dogs had metastasis of histiocytic sarcoma in the CNS the dogs was an eight-years-old, Rottweiler, male, with a primary (Dobermann, male, eight-years-old; and Rottweiler, female, thoracic limb neoplasm, while the other was a two-years-old, thenine-years-old). telencephalon In and one diencephalon case, there were(Fig.4A multifocal nodular firm and white lesions (1 to 2.5cm in diameter) which involved mixed-breed, female with a primary pelvic limb neoplasm. area (1.5cm in diameter) in the dorsal part of the cerebellum piriform lobe (Fig.4B ). The second case In both cases, a focal white and hard well‑ defined nodular (Fig.3E and 3F neoplasticwas characterized cells located by pinpoint inside bloodreddish vessels lesions (Fig.4C involving the ), which microscopically consisted of and interspersed) was by observed, bone and withcartilaginous a gritty aspect matrix. on the cut rounded to oval, occasionally indented, hyperchromatic). nuclei.These surface. Histologically, the neoplastic cells were spindle-like cells were round, with abundant eosinophilic cytoplasm,
Pesq. Vet. Bras. 38(10):1989-1998, outubro 2018 1994 Lilian C. Heck et al.
Fig.4. Metastatic histiocytic sarcoma. (A B C HE, obj.20x. (D ) One case had a focal nodular whitish neoplasm in the telencephalon. ( ) The second case had pinpoint reddish areas involving the piriform lobe and white matter. ( ) Neoplastic histiocytes were mostly located inside blood vessels. ) Neoplastic cells were round, with abundant eosinophilic cytoplasm, and round to oval, occasionally indented, nuclei. Numerous multinucleated neoplastic cells and mitotic figures were also observed. HE, obj.20x. In addition to that, numerous multinucleated neoplastic cells Fig.4D). lesions consisted of focal nodular lesions in the telencephalon. apocrine sweat gland carcinoma and synovial sarcoma), the Lungand a carcinomahigh mitotic index were also observed ( DISCUSSION
Two dogs presented metastasis of lung carcinoma in The diagnosis of CNS metastases in the 78 dogs of the present the CNS (Golden Retriever and Pointer breeds). Both were of neoplastic cells in the CNS identical to those observed females, with a mean age of 10-years-old (age range of study was mainly based on the histopathological identification nine to 11-years-old). One of these cases was diagnosed as more frequent than primary neoplasms in the CNS (42.23%). adiameter) papillary ( Fig.5Apulmonary carcinoma with focal metastasis in in the primary sites. Metastatic neoplasms (57.77%) were the cerebellum (soft and white nodular area with 2.5cm in explained by the advances in chemotherapeutic treatments, ), while the second case was diagnosed as a This increased frequency of metastatic neoplasms may be large-cellinside blood carcinoma vessels ofand the expanding lung with onlyinto microscopicthe cerebral lesions,plexus, whichcerebellum, were telencephalon, characterized diencephalon,by multifocal andmetastasis mesencephalon located maywhich, expand in addition the odds to aof longer a malignant dog life neoplasm expectancy, to spread provides to (Fig.5B). thean increase CNS (Song in the et al.survival 2013). time Another of dogs important with neoplasms, factor is andthe increase in the life expectancy of dogs (Song et al. 2013), as Other cases occurred individually. Among these, nasal cavity carcinoma, theseen literature in the dogs of an of averagethe present age ofstudy, presentation which presented of 9.6-years a mean‑old thyroidThe carcinomaother seven and neoplasms pheochromocytoma with metastasis exhibited to multifocal the CNS (Snyderage close et to al. 10-years-old, 2008, Higgins which et al. is 2017).similar to that described in Since the main route of metastasis to the CNS is via the (micrometastasis). In the other cases (cholangiocarcinoma metastases(Fig.5C), malignant in the CNS peripheral and were observednerve sheath only tumormicroscopically (Fig.5D), hematogenous pathway, secondary neoplasms usually have a multifocal distribution (McEntee & Dewey 2013), similar Pesq. Vet. Bras. 38(10):1989-1998, outubro 2018 Pathological features of 78 metastatic or multicentric neoplasms involving the central nervous system in dogs 1995
Fig.5. Metastatic lung carcinoma and other metastatic neoplasms. (A cerebellar hemisphere in a papillary pulmonary metastatic carcinoma. (B) Metastatic large cell carcinoma of the lung had multifocal metastasis inside blood vessels of the cerebellum. HE, obj.20x. ()C A) focalMetastatic white nodularcholangiocarcinoma area (2.5cm inand diameter) malignant replaced peripheral part nerveof the sheath tumor in the telencephalon. (D E) Metastatic F) Metastatic ) Metastatic neoplastic cells infiltrated the adjacent neuropil. HE, obj.20x. ( cholangiocarcinoma and malignant peripheral nerve sheath tumor with focal nodular lesions in the telencephalon. ( neoplastic cells infiltrated the adjacent neuropil. HE, obj.10x.
the stasis of tumor emboli, mainly in the transition of the mostto what commonly has been neuroanatomic observed in thisregion study, affected in which by metastasis 73.07% meningeal blood vessels decreases rapidly, which facilitates inof the CNSneoplasms (Santos were et al. multifocal. 2001, Snyder The et telencephalon al. 2008), as inis the becausegrey and theywhite represent matter (Cantile a large &portion Youssef of 2016). the dog Mixed-breed population dogs were the most affected in the present study, probably additionpresent study.to the Thisfact thatmay this be regionrelated is to the the largest abundant area bloodof the CNSsupply in ofdogs this (Fenner area, which 1990). favors Furthermore, neoplastic the cell caliber embolism, of the in the large number of cases of mammary metastatic neoplasms in Brazil. Female dogs were most affected than males due to
Pesq. Vet. Bras. 38(10):1989-1998, outubro 2018 1996 Lilian C. Heck et al. observed, since these are tumors almost exclusive of females (Oliveira et al. 2003). occasional areas of hemorrhage (Bertazzolo et al. 2005). These metastatic neoplasms in the CNS of dogs, differing from findings are similar to those observed in the present study, Mammary gland neoplasms were the most frequent inassociated which the hemorrhage. neoplastic HSAcells metastases were distributed may occur multifocally through major metastatic CNS tumor in dogs (Snyder et al. 2008, and predominantly around vascularized regions with previousSong et al. descriptions, 2013). Predisposing in which hemangiosarcoma factors such as unspayed was the involved, these occur mainly through the hematogenous the lymphatic or blood vessels; however, when the CNS is common in the region of the present study, are related to the (Hayashi et al. 2007). In addition to the histopathology that femaleoccurrence dogs of and mammary the use neoplasmsof progestin in contraceptives, dogs (Oliveira et which al. 2003), are route, since the CNS has an inefficient lymphatic system making it the main neoplasm of dogs in Brazil (Daleck et al. resonance are commonly used for early diagnosis of these confers a definitive diagnosis, imaging tests such as magnetic to the geographic location. According to the international 1998).literature, The incidence41% to 53% of malignant of mammary neoplasms tumors varies of accordingdogs are tumors.(Kippenes The et images al. 1999). are characterized by multifocal masses, withLymphoma contrasting is densities the most due common to intratumoral hematopoietic hemorrhages tumor malignant73% of malignant (Nunes mammary et al. 2017), neoplasms while studies (Oliveira performed et al. 2003, in the South of Brazil have shown a proportion of 68% and inthis dogs, neoplasm with thein dogs generalized may be observed form as inthe 5-12% most ofcommonly the cases reported (Valli et al. 2017). The involvement of the CNS by Oliveira Filho et al. 2010). There are several types of mammary carcinomas, which present differences in morphology and (Higginsor affected et as al. a 2017),secondary of which organ thein a CNSmulticentric may be conditionprimarily prognosis.micropapillary The mostcarcinoma. frequent Anaplastic types of mammary carcinoma neoplasms is highly involved, when the neoplasm is located exclusively in the CNS, inaggressive the present and studyinvasive were (malignant) anaplastic and carcinoma presents aand high invasive degree usually involves the leptomeninges or blood vessels (Cantile of metastasis to different tissues (Goldschmidt et al. 2017). (Sisó& Youssef et al. 2017).2016, ThisMandara is the et most al. 2016),common as form seen observed in the cases and In contrast, invasive micropapillary carcinoma commonly gross lesion observed. Instead of that, primary lymphomas may vary from 90 to 120 days (Gamba et al. 2017). Both described,are usually where characterized meninges by and the vessels formation were affectedof grayish, with soft no presents nodal metastasis and short global survival, which neoplasmsmicroscopic are aspects spread observed through in the the present hematogenous study of neoplastic pathway and poorly defined single masses (Higgins et al. 2017). (Vandevelde et al. 2012), which was corroborated by the Lymphomas can be classified into several types and it is suggested that each classification presents a distinct form cellspresented within also blood metastasis vessels associated in the meninges, to the absence characterizing of gross ofas CNSobserved distribution. in these However, cases, theare diffusecommon involvement in most of of the lesionsa leptomeningeal (multiple micrometastasis). carcinomatosis. Still, In this the twocondition, neoplasms the meningeslymphomas and subtypes. the fulfillment Still other of neuroanatomic the lumen of blood regions, vessels, such as the neuropil, periventricular areas, pituitary gland and are deposited mainly in the subarachnoid space. Once these choroid plexus, are also common sites of metastases. Among neoplasticcells are established, cells reached they the spread meninges through through the blood cerebrospinal flow and as observed in the present study (Grossman & Krabak 1999). lymphoma and subtypes, diffuse largemore B-cell than lymphoma12 have been (Sisó identified et al. 2017). in fluidHemangiosarcoma to other regions of the(HSA) CNS, is with a common a diffuse malignantmetastasis, the CNS. The most prevalent subtypes are peripheral T-cell neoplasm in dogs, and may represent up to 5% of the causes of death due to neoplasms in this species (Flores et al. 2012). In theMelanoma present is thework, main however, melanocyte the tumor immunophenotyping of dogs (Harvey et al.of It may originate in different tissues, but the spleen is the lymphomas1981) usually was involving not performed. the digits and the oral mucosa, most commonly affected organ (Flores et al. 2012), being considered one of the main conditions observed in spleens Goldschmidt 2017). Around 95% of these cases are malignant, which is similar to the observed in this study (Goldschmidt & is reported as the major metastatic tumor in the CNS of dogs brain (Bolon et al. 1990). In humans, 15.7% of the metastatic after splenectomy in dogs (Bandinelli et al. 2011). This tumor withCNS tumors metastases have mainlybeen found to the to lymph be melanomas nodes, lungs (Vieth and & Odomto the
(Snyder et al. 2008, Song et al. 2013), while in the present study HSA was the second most identified neoplasm. Involvement 1965),observed whereas in the presentin dogs this study corresponds (6.41%). Primary to 3.4% melanomas (Snyder et al., in of the CNS in dogs with HSA was of approximately 15% in 2008)the CNS and are 7.8% rare and (Song usually et al. are 2013), limited which to the are leptomeninges similar to the this study, which may vary from 14.2% (Waters et al. 1989) to 30% (Flores et al. 2012) in dogs that died due to HSA. These tumors may be classified as primary or secondary in the (KimDifferentiation et al. 2009). of primaryHowever, and in themetastatic present melanomastudy, all cases may CNSmay (Gaborhave a multicentric& Vanderstichel behavior 2006), (Flores however et al. some 2012). authors In all formed well-defined multifocal nodules involving the neuropile. have contested these classifications, since this neoplasm respectively, of oral or skin neoplasms (Kim et al. 2009), as be difficult and depends mainly on the absence or presence, cases presented here, there was a primary tumor lesion at a distantcorrespond site, and,microscopically thus, all cases to werethe proliferation considered metastatic. of spindle evidencedin the CNS in are this generally study where distributed all cases multifocally presented primaryand are Grossly,cells arranged this neoplasm in vascular exhibits spaces soft of differentreddish nodules, diameters which and digital or oral mucosa neoplasms. The metastases of melanoma
grossly pigmented - except for amelanotic melanomas - while Pesq. Vet. Bras. 38(10):1989-1998, outubro 2018 Pathological features of 78 metastatic or multicentric neoplasms involving the central nervous system in dogs 1997 microscopically it presents similar features to the primary tumor (Summers et al. 1995), as in the present study. Osteosarcoma is the most common bone neoplasm of Neoplasms were mostly multifocal, and the telencephalon dogs, and, frequently, affects the appendicular skeleton of was the most commonly affected neuroanatomic region. invasiveMammary micropapillary neoplasms carcinoma were the mostand comedocarcinoma. frequent, and the aggressive tumors that may cause local bone destruction, Inmost the commonly cases of anaplasticobserved types carcinoma were anaplastic and micropapillary carcinoma, largeinvade and the giantadjacent breeds soft tissues,(Tilley &and Smith have 2015). a high metastaticThese are carcinoma, a multifocal microscopic involvement of the CNS of osteosarcoma, and metastasis to the CNS are not common potential. The lungs are the main organ affected by metastasis was observed, with an absence of gross lesions. 43 osteosarcomas in dogs submitted to necropsy, only one LymphomaHemangiosarcoma predominantly was the second involved most the common meninges neoplasm, and the (Trost et al. 2012). In a previous study that evaluated lumenwith a multifocalof blood vessels. involvement. case presented a CNS metastasis (Trost et al. 2012), which is neoplasms involving the CNS provides important data to similarhad the to same the presentdistribution study, (dorsal where onlypart twoof the cases cerebellum), of 78 had The collection and pathological analysis of metastatic osteosarcomasuggesting a possible metastasis. predilection In both cases, for this these region. were focal and Histiocytic sarcoma may affect the CNS primarily or as neurological clinical signs, in order to obtain a conclusive a metastatic spread. Primary CNS histiocytic sarcoma often diagnosis.clinical veterinarians, It is essential when that these metastatic are facing conditionsneoplasms with are originate in the leptomeninges, or forming a focal and solitary considered as differential diagnosis in these cases, aiming subdural mass, and rarely presents extracranial metastasis prevention and appropriate treatments. Conflict of interest statement.
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