RESUMO
OBJECTIVE: This two-part study describes the clinical usefulness and value of ultrasound and magnetic resonance imaging (MRI) in dogs and cats with ocular (n=30) and orbital diseases (n=31). MRI and ultrasonography characteristics are described in single cases with ocular and orbital disease. MATERIAL AND METHODS: Ultrasonography and MRI were performed in 15 dogs and 15 cats with intraocular neoplasia or intraocular inflammatory disease. RESULTS: In all patients with intraocular neoplasia, sonography revealed masses with increased echogenicity and fairly uniform echotexture, thus allowing the tentative diagnosis of an intraocular tumour. In these cases, MRI often proved to be a valuable diagnostic tool in showing the complete extent of intraocular lesion. An additional benefit of MRI was seen in the tissue characterization of tumours based on MRI signal characteristics and pattern of contrast enhancement. Discreet intraocular inflammatory alterations, in particular to the anterior and posterior segment of the eyeball, were more clearly shown by ultrasound than by MRI. Neoplasia could be excluded and inflammatory disease was successfully diagnosed using MRI due to the different image sequences with or without contrast medium administration. Traumatic ruptures of the lens capsule and the globe after trauma were depicted more clearly with MRI. CONCLUSIONS AND CLINICAL RELEVANCE: When opacity of the anterior eye segment is present, various intraocular changes can be quickly diagnosed by ultrasound with high accuracy, without requiring anaesthesia of the patient. MRI of the globe allows differentiation of diverse pathologies, gives detailed information of infiltration in orbital structures and the exact degree of ocular lesions after trauma. This additional evidence often makes it easier to predict the correct prognosis and choose the best therapy.
Assuntos
Doenças do Gato/diagnóstico por imagem , Doenças do Gato/patologia , Doenças do Cão/diagnóstico por imagem , Doenças do Cão/patologia , Oftalmopatias/veterinária , Animais , Gatos , Cães , Oftalmopatias/diagnóstico por imagem , Oftalmopatias/patologia , Neoplasias Oculares/diagnóstico por imagem , Neoplasias Oculares/patologia , Neoplasias Oculares/veterinária , Inflamação/diagnóstico por imagem , Inflamação/patologia , Inflamação/veterinária , Imageamento por Ressonância Magnética/veterinária , Prognóstico , UltrassonografiaRESUMO
Two cases of disseminated fatal toxoplasmosis of a pet mouse and a red panda are described. The pet mouse had a private owner; the red panda lived in a zoological garden in Saxony. At necropsy, both animals suffered from a systemic toxoplasmosis. A severe necrotizing hepatitis was the main histological feature in both animals. Parasitic cysts could be abundantly found in the liver, moderately in the brain and in a low number in other organs. With the PAS-reaction, cysts showed a weak staining in the mouse and a strong staining in the red panda. Diagnosis was confirmed by PCR and immunohistochemistry.
Assuntos
Ailuridae/parasitologia , Camundongos/parasitologia , Doenças dos Roedores/parasitologia , Toxoplasmose Animal/diagnóstico , Animais , Animais de Zoológico , Encéfalo/parasitologia , Evolução Fatal , Feminino , Coração/parasitologia , Hepatite Animal/parasitologia , Hepatite Animal/patologia , Imuno-Histoquímica/veterinária , Fígado/parasitologia , Fígado/patologia , Masculino , Animais de Estimação , Reação em Cadeia da Polimerase/veterinária , Doenças dos Roedores/diagnóstico , Toxoplasmose Animal/parasitologiaRESUMO
The first part of our study (Müller et al., 2009) characterized angiogenesis in the equine cycling ovary through histomorphological and immunohistochemical examinations (vascular endothelial growth factors A and B [VEGF A, VEGF B], vascular endothelial growth factor receptors 1 and 2 [VEGF-R1, VEGF-R2], vascular angiopoietins 1 and 2 [Ang1, Ang2], angiopoietin receptor [Tie2], and von Willebrand Factor). Since angiogenesis plays an important role in development and growth of numerous tumours, the second part of our study involved a similar examination of 70 equine granulosa cell tumours (GCTt). The results of the second study were compared with those of the normal equine ovary. Certain similarities in the expression pattern could be detected between normal, cyclical ovaries (Müller et al., 2009) and GCTt. The immunoreactivity of granulosa cells and Leydig-like cells in GCTt resembles granulosa cells and luteinized thecal cells in periovulatory cycling ovaries. The neoplastic cells support circulation, supply and growth of GCTt by contributing to angiogenesis.
Assuntos
Indutores da Angiogênese/metabolismo , Tumor de Células da Granulosa/veterinária , Doenças dos Cavalos/metabolismo , Neovascularização Patológica/veterinária , Animais , Feminino , Regulação Neoplásica da Expressão Gênica/fisiologia , Tumor de Células da Granulosa/irrigação sanguínea , Tumor de Células da Granulosa/metabolismo , Tumor de Células da Granulosa/patologia , Doenças dos Cavalos/patologia , Cavalos , Neovascularização Patológica/metabolismoRESUMO
The aim of the present study was to characterize the morpho-functional features of endometrosis in barren and foaling mares, using both conventional histopathological and immunohistochemical methods. Endometrial biopsy samples were collected during the physiological breeding season from 159 estrous, clinically healthy mares (mean age 12 years), and the quality and degree of endometrosis was histomorphologically defined. The mares were bred and those that foaled were put in the foaling group whereas those that did not foal were placed in the barren group. Foaling mares were then compared with barren mares. Sixty-four percent (101/159) of uterine samples showed varying degrees of endometrosis and were used for this study. The sample population consisted of 51 barren and 50 foaling mares suffering from endometrosis. Expression of steroid hormone receptors (estrogen receptor, progesterone receptor) and endometrial protein secretion patterns (uteroglobin [UG], uterocalin [UC], calbindin(D9k) [CAL], uteroferrin [UF]) was evaluated by immunohistochemistry (barren mares N = 51, foaling mares N = 31). In comparison with unaffected glands, fibrotic glands generally showed a cycle-asynchronous, partially patchy protein expression pattern which is interpreted as a sign of endometrial maldifferentiation within fibrotic areas. In barren mares (N = 51) more than half of biopsy samples (27/51) showed a destructive mostly moderate (20/27) type of endometrosis. In affected glands, staining for UG (17/21) was decreased (P < 0.001). Foaling mares (N = 50) frequently showed a mild, nondestructive endometrosis (35/50). Compared with barren mares, foaling mares had statistically (P < 0.05) more often a cycle-synchronous or increased UG expression pattern within fibrotic glands. Obvious deviations of either UG or UC rarely occurred. Within fibrotic foci, UF often demonstrated a cycle-synchronous or more intense expression pattern in both foaling (28/31) and barren mares (41/51), compared with healthy glands. Mares of both groups showed a cycle-asynchronous staining for estrogen receptor and progesterone receptor in the stromal cells in areas of periglandular fibrosis and the glandular epithelia. These findings indicate that affected areas become independent of the uterine control mechanisms and exhibit specific differentiation dynamics. Immunohistochemical investigations showed that the secretory patterns differ between barren and foaling mares. The findings in this study should be considered as a useful addition to the "classical" Kenney categorization.
Assuntos
Endometriose/veterinária , Doenças dos Cavalos/patologia , Infertilidade Feminina/veterinária , Animais , Calbindinas , Endometriose/patologia , Endométrio/metabolismo , Endométrio/patologia , Feminino , Cavalos , Imuno-Histoquímica , Infertilidade Feminina/complicações , Infertilidade Feminina/epidemiologia , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Proteína G de Ligação ao Cálcio S100/metabolismo , Uteroglobina/metabolismoRESUMO
Cyclical ovaries of 18 mares were examined histologically and immunohistochemically for vascular endothelial growth factor A and B (VEGF A; VEGF B), angiopoietin1 and 2 (Ang1; Ang2), vascular endothelial growth factor receptor 1 and 2 (VEGF-R1; VEGF-R2), angiopoietin receptor (Tie2) and von Willebrand factor. The most intensive coexpression of the examined factors and receptors was detected in the periovulatory period, when a distinctive ovarian angiogenesis takes place, being essential for tertiary follicle maturation and for the endocrine function of the Corpus luteum. Based on the immunohistochemical results, VEGF A, Ang2, VEGF-R2 and Tie2 in particular seem to play a significant role on angiogenesis during follicular and luteal development in the mare, while Ang1 supports vessel stabilisation. The findings of luteal regression and follicular atresia showed that, in the absence of VEGF A, Ang2 and its receptor Tie2 contribute substantially to vessel regression and therefore to luteolysis and follicular atresia.
Assuntos
Cavalos/fisiologia , Neovascularização Fisiológica/fisiologia , Ovário/irrigação sanguínea , Ovário/metabolismo , Angiopoietinas/metabolismo , Animais , Feminino , Cavalos/anatomia & histologia , Imuno-Histoquímica , Ovulação/fisiologia , Receptor TIE-2/metabolismo , Receptores de Fatores de Crescimento do Endotélio Vascular/metabolismo , Fatores de Crescimento do Endotélio Vascular/metabolismo , Fator de von Willebrand/metabolismoRESUMO
Although alterations in patterns of protein secretion revealed in uterine flushings from mares suffering from endometrosis have been described, little is known about alterations at the cellular level. Hence, the aim of this study was to characterize deviations in patterns of uterine gland secretion patterns using endometrial biopsies, histochemical and newly established immunohistochemical methods. Forty-eight endometrial biopsies were obtained from mares suffering from various types of endometrosis (active and inactive, destructive and non-destructive) and degree (mild to severe) were analyzed for expression of the proteins uteroglobin, uteroferrin, calbindinD9k and uterocalin as representatives of endometrial proteins detectable by immunohistochemistry using polyclonal antibodies. Glycogen was identified using the PAS-reaction and mucopolysaccharides were stained with alcian blue. Uterine glandular epithelia within fibrotic foci mostly revealed a protein and carbohydrate pattern of expression which was independent of hormonal changes during the estrous cycle. In comparison to non-affected glands, most epithelial cells within periglandular fibrosis exhibited decreased immunostaining intensity for proteins, especially when there was destructive endometrosis. However, uteroferrin staining intensity was strong within areas of severe destructive endometrosis. Moreover, only few basal glandular epithelial cells, especially those in cystic glands, stained for mucopolysaccharides that are typically seen within the luminal epithelia. Usually a single fibrotic focus caused only slight alterations in glandular proteins and carbohydrate reaction patterns, so that only more severe endometrosis lead to deviations which were detectable in uterine flushings. The highly sensitive methods used in the present study allow studies of uterine secretion patterns in the context of routine assessment of endometrial biopsies.
Assuntos
Endometriose/veterinária , Endométrio/metabolismo , Perfilação da Expressão Gênica/veterinária , Regulação da Expressão Gênica/fisiologia , Doenças dos Cavalos/metabolismo , Imuno-Histoquímica/veterinária , Fosfatase Ácida/metabolismo , Animais , Calbindinas , Metabolismo dos Carboidratos , Endometriose/metabolismo , Feminino , Glicogênio/metabolismo , Glicosaminoglicanos/metabolismo , Cavalos , Isoenzimas/metabolismo , Lipocalinas/genética , Lipocalinas/metabolismo , Proteínas/metabolismo , Proteína G de Ligação ao Cálcio S100/genética , Proteína G de Ligação ao Cálcio S100/metabolismo , Fosfatase Ácida Resistente a Tartarato , Uteroglobina/genética , Uteroglobina/metabolismoRESUMO
Anovulatory haemorrhagic follicles (AHFs) are often the reason for ovulation failure in the mare. As the underlying factors that lead to AHF development are not well understood, it was of interest to investigate the vascularization of AHFs compared with normal follicles and corpora lutea (controls). In the present study, the ovarian cell populations investigated immunohistochemically included granulosa and luteal cells as well as various vascular structures. None of these cell types showed differences in the expression of vascular endothelial growth factor A (VEGF-A) between control ovaries containing normal follicles and corpora lutea and ovaries with AHFs. In contrast, a considerable reduction in the proportion of Flk-1-expressing cells, together with a decreased intensity of staining, was apparent in the AHFs. This greatly reduced expression of Flk-1 in the luteinized cells and the vascular structures of AHFs may lead to a distinct decrease in the potential pro-angiogenic activity of VEGF-A in these structures compared with the situation in normal follicles and corpora lutea. Furthermore, the authors suspect that the distinct expression of angiopoietin2 and VEGF-A seen in the cells within the inner fibrous layers of the AHFs was caused by hypoxia resulting from deficient vascularization, as suggested by the irregularity of the capillaries present in the luteinized wall of the AHF. In addition, whereas LH-receptor (LH-R) expression occurred uniformly in all stages of development of the corpora lutea in normal control ovaries, there was highly variable labelling for LH-R in all the AHFs examined, thereby indicating a possible numerical deficiency of LH-receptors in AHFs. The authors concluded that, despite the apparent expression of sufficient VEGF-A in the AHFs allows ovulation and corpus luteum formation, a relative lack of receptor, Flk-1, effects the pro-angiogenic activity of VEGF-A which could be a reason for ovulation failure associated with AHF formation.
Assuntos
Anovulação/veterinária , Hemorragia/veterinária , Doenças dos Cavalos/patologia , Doenças Ovarianas/veterinária , Folículo Ovariano/química , Folículo Ovariano/patologia , Angiopoietina-2/análise , Animais , Anovulação/metabolismo , Anovulação/patologia , Capilares/patologia , Corpo Lúteo/irrigação sanguínea , Corpo Lúteo/química , Corpo Lúteo/patologia , Feminino , Hemorragia/metabolismo , Hemorragia/patologia , Doenças dos Cavalos/metabolismo , Cavalos , Imuno-Histoquímica , Luteinização , Doenças Ovarianas/metabolismo , Doenças Ovarianas/patologia , Folículo Ovariano/irrigação sanguínea , Receptores do LH/análise , Fator A de Crescimento do Endotélio Vascular/análise , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/análiseRESUMO
Previous studies have shown that the equine uterus produces many progesterone-dependent proteins throughout gestation. In particular, uterocalin and uteroferrin are detectable using electrophoresis or blot analyses but information regarding the immunohistochemical placental distribution of these two proteins is rare and information regarding uteroglobin is still lacking. The aim of the present study was to co-immunolocalise these three secretory proteins in the mare's uterus throughout gestation in an effort to understand their functional role in the maintenance of pregnancy. Therefore, endometrial biopsy samples were obtained from 20 pregnant mares between 16 and 309 days of gestation and labelled immunohistochemically for uteroglobin, uteroferrin and uterocalin. Uteroferrin remained detectable in almost every endometrial gland at all stages but with an increase in staining intensity as gestation advanced. The most progesterone-dependent protein, uterocalin, showed variable staining throughout gestation with the most intense labelling in early pregnancy and during the period of endometrial cup reaction. Uteroglobin secretion was only detectable in traces and only in individual glands throughout gestation. The results indicate that uterocalin and uteroferrin, but not uteroglobin, may play important roles in supplying nutrients for the conceptus, thereby contributing to the maintenance of pregnancy. However, further investigations are necessary to understand the role of uteroglobin during gestation.
Assuntos
Fosfatase Ácida/metabolismo , Cavalos/fisiologia , Isoenzimas/metabolismo , Lipocalinas/metabolismo , Placenta/metabolismo , Uteroglobina/metabolismo , Útero/metabolismo , Animais , Feminino , Imuno-Histoquímica/veterinária , Placenta/citologia , Gravidez , Fosfatase Ácida Resistente a TartaratoRESUMO
Delayed emergence from anaesthesia and neurological disturbances have been reported in patients undergoing parathyroidectomy who received methylene blue (MB) pre-operatively. We hypothesised that MB would decrease propofol requirements. The Bispectral index (BIS) and a target-controlled infusion of propofol were used in two groups of 11 matched patients. Patients in one group were pretreated with MB. During induction, clinical sedation scores and BIS values were significantly lower at the predicted effect-site propofol concentration of 2 microg x ml(-1) in the MB compared with the control group. Intra-operatively, although similar BIS values were achieved in the two groups, patients pretreated with MB required a mean 50% lower dose of propofol compared with controls. In view of these findings, care should be taken to ensure an adequate depth of anaesthesia by titrating the administration of anaesthetic agents whenever MB is infused peri-operatively.
Assuntos
Anestésicos Intravenosos/administração & dosagem , Corantes/farmacologia , Azul de Metileno/farmacologia , Propofol/administração & dosagem , Idoso , Anestesia Intravenosa/métodos , Estudos de Casos e Controles , Esquema de Medicação , Sinergismo Farmacológico , Eletroencefalografia/efeitos dos fármacos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , ParatireoidectomiaAssuntos
Morte Encefálica/diagnóstico , Isquemia Encefálica/diagnóstico , Eletroencefalografia , Complicações Intraoperatórias/diagnóstico , Encéfalo/irrigação sanguínea , Morte Encefálica/fisiopatologia , Isquemia Encefálica/fisiopatologia , Procedimentos Cirúrgicos Cardíacos , Evolução Fatal , Feminino , Humanos , Complicações Intraoperatórias/fisiopatologia , Pessoa de Meia-Idade , Monitorização IntraoperatóriaRESUMO
Benign (n=33) and malignant metastasizing (n=1) granulosa cell tumours (GCTs) from 34 mares aged 3-21 years, and normal (control) ovaries from nine mares aged 3-10 years, were examined histologically and immunohistochemically (for inhibin alpha, glutathione S-transferase alpha [GSTalpha], c-erbB-2 oncoprotein [cerb], cytokeratin, vimentin, desmin and alpha-actin), the results being related where appropriate to clinical signs and endocrinological data. Availability permitting, serum samples from GCT-affected mares before and several weeks after ovariectomy were examined for the following hormones: oestradiol, progesterone and testosterone (by radioimmunoassay); and inhibin B (by a cross-reactive ELISA). Histological examination revealed that the GCTs were predominantly well differentiated neoplasms. The metastasizing GCT differed immunohistochemically from the benign GCTs in respect of the expression patterns of vimentin, cerb and GSTalpha in the granulosa cells. A notable feature was the presence of Leydig-like cells in mares with stallion-like behaviour or elevated serum testosterone, or both. GSTalpha immunolabelling indicated that the Leydig-like cells were potential producers of steroid hormone. From the immunohistochemical and endocrinological findings it was concluded that GCTs produce abnormally high concentrations of inhibin, which reduce the release of follicle-stimulating hormone, leading to atrophy of the contralateral ovary-a finding in 27 of the mares.
Assuntos
Biomarcadores Tumorais/metabolismo , Tumor de Células da Granulosa/veterinária , Doenças dos Cavalos/patologia , Técnicas Imunoenzimáticas/veterinária , Neoplasias Ovarianas/veterinária , Animais , Feminino , Hormônios Esteroides Gonadais/sangue , Tumor de Células da Granulosa/metabolismo , Tumor de Células da Granulosa/patologia , Doenças dos Cavalos/metabolismo , Cavalos , Inibinas/metabolismo , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Ovariectomia/veterinária , Ovário/metabolismo , Ovário/patologiaRESUMO
Primary and secondary neoplasms of the canine and feline heart are uncommon. During a 2-year period, 83 dogs suffering from primary cardiac (n=11), extracardiac benign (n=6) or malignant (n=66) tumours and 30 cats with primary cardiac (n=1) or extracardiac (n=29) malignant tumours were examined. Echocardiography revealed four cases of primary cardiac neoplasms in dogs, but secondary heart tumours were not detected. After necropsy, tissue samples from the heart and tumours were examined histologically and immunohistochemically. In dogs, primary neoplasms included seven haemangiosarcomas, two chemodectomas, one rhabdomyosarcoma, and one neurofibrosarcoma. In 24 of 66 dogs examined, metastases of extracardiac neoplasms were found in the heart (15 carcinomas, six malignant lymphomas, three haemangiosarcomas). In cats, one case of primary haemangiosarcoma of the pericardium and five cases of secondary cardiac tumours (two malignant lymphomas, three carcinomas) occurred. Cardiac neoplasms in cats were not identified clinically but were detected by detailed gross sectioning of the heart (n=2) or histopathological examinations (n=3). This study showed an unexpectedly high number (36%) of dogs with cardiac metastases.
Assuntos
Doenças do Gato/patologia , Doenças do Cão/patologia , Neoplasias Cardíacas/veterinária , Hemangiossarcoma/veterinária , Linfoma de Células B/veterinária , Neurofibrossarcoma/veterinária , Paraganglioma Extrassuprarrenal/veterinária , Animais , Gatos , Cães , Neoplasias Cardíacas/patologia , Neoplasias Cardíacas/secundário , Hemangiossarcoma/patologia , Hemangiossarcoma/secundário , Linfoma de Células B/patologia , Metástase Neoplásica , Neurofibrossarcoma/patologia , Neurofibrossarcoma/secundário , Paraganglioma Extrassuprarrenal/patologia , Paraganglioma Extrassuprarrenal/secundárioRESUMO
The objective of this study was to investigate the effects of four different concentrations (groups II-V) of orally administered zearalenone (ZON) over a feeding period of 35 days on parts of the genital tract of 75 day-old female piglets in comparison to a control group (I). In order to determine possible dose related characteristics for a ZON intoxication in ovaries and uteri, histomorphological (HE and Azan stained slides) and immunohistochemical methods [expression patterns of estrogen (ER) and progesterone (PR) receptor, proliferating cell nuclear antigen (PCNA)] were carried out. Using these methods, there were no obvious (immuno-) histomorphological differences within the treatment groups or in comparison to the control group. Nevertheless, compared to the group I, statistical analyses of all parameters investigated revealed significance only in the increased mitotic activity of muscle cells in the uterinelamina muscularis in treatment group V.
RESUMO
Infections caused by classical tubercle bacilli are rare during the last years. Nevertheless, diseases caused by other mycobacteria have to be considered clinically and in diagnostic pathology especially in cases of immunosuppression and due to their potential zoonosis risk. An infection by mycobacteria was diagnosed in four animals (Mayotte Maki, Blue-headed Parrot, Patagonian sealion, Beagle) necropsied between 1995 and 2002 in the Institute of Veterinary-Pathology of the University of Leipzig. The Maki, the blue-headed parrot and the dog showed a disseminated character of the disease caused by Mycobacterium genavense (monkey and bird) resp. Mycobacterium avium (dog), while an open chronical tuberculosis of the lungs due to a pathogenic member of Mycobacterium tuberculosis complex was observed in the seal. All these bacteria are potential causes of zoonoses. So, if granulomatous or disseminated histiocytic alterations are detected in diagnostic pathology, mycobacterial infections should always be included in differential diagnoses and require careful aetiological investigations by histopathological and bacteriological methods.
Assuntos
Animais Domésticos , Animais de Zoológico , Infecções por Mycobacterium não Tuberculosas/veterinária , Micobactérias não Tuberculosas/isolamento & purificação , Animais , Doenças das Aves/patologia , Doenças do Cão/patologia , Cães , Humanos , Lemur , Infecções por Mycobacterium não Tuberculosas/epidemiologia , Infecções por Mycobacterium não Tuberculosas/patologia , Micobactérias não Tuberculosas/patogenicidade , Papagaios , Doenças dos Primatas/patologia , Focas Verdadeiras , ZoonosesRESUMO
We describe three patients with acute chiasmal visual field loss caused by hemorrhage within an intrachiasmal arteriovenous malformation. One patient had five episodes; vision improved three times without treatment and twice after surgical decompression. Surgical intervention restored vision in two of the three patients. The role for surgery is indefinite, but may be indicated if the visual defect remains static for 1 week or progresses. Decompression is likely to be most effective if done early. The approach to the optic chiasm should be transcranial, not transsphenoidal. A radiologically normal sella turcica favors the diagnosis of chiasmal apoplexy in the acute chiasmal syndrome.
Assuntos
Malformações Arteriovenosas/diagnóstico , Hemorragia Cerebral/diagnóstico , Quiasma Óptico/irrigação sanguínea , Adulto , Malformações Arteriovenosas/complicações , Hemorragia Cerebral/etiologia , Feminino , Humanos , Masculino , Transtornos da Visão/etiologiaRESUMO
Three patients had a syndrome of progressive or long-standing visual loss, pale disk edema, and optociliary veins, indicating that a spheno-orbital meningioma had invaded the anterior perioptic meninges. To diagnose this syndrome, one must distinguish "disk edema" from "papilledema"; although both result from increased pressure within the perioptic subarachnoid space, disk edema is caused by a variety of lesions just behind the globe, whereas papilledema is caused by remote lesions that raise intracranial pressure. Optociliary veins reflect the slowness of progression of both processes. This ophthalmoscopic diagnosis carries important implications, namely, that the tumor grows very slowly and that surgical treatment will not improve vision. Therefore, excision may not be the treatment of choice.