Malignant dysembryoplastic neuroepithelial tumour in a zebrafish (Danio rerio)

Neuroectodermal tumours in man, including medulloblastoma, medulloepithelioma, neuroblastoma, esthesioneuroblastoma, primitive neuroectodermal tumour and dysembryoplastic neuroepithelial tumour, typically occur in children and young adults. These tumour types are occasionally observed in juvenile and adult zebrafish (Danio rerio) either as induced tumours in carcinogen-exposed zebrafish or as an incidental finding in zebrafish≥2years of age. An adult zebrafish submitted for routine histological examination was sent for a second opinion consultation after an uncharacteristic brain mass was identified. Microscopically, the expansile and infiltrative extracortical mass arising from the cerebellum had a diffuse microcystic pattern with solid hypercellular regions occupying 80% of the extrameningeal space and effacing the endomeninx and significantly displacing the metencephalon. The mass was composed of dense sheets of oligodendrocyte-like cells, random neurons and pseudocysts containing 'floating neurons' within a scant mucinous matrix. Neoplastic cells demonstrated positive perinuclear and intracytoplasmic expression of S-100. Malignant dysembryoplastic neuroepithelial tumour was diagnosed based on the histological features of the brain mass, which were indistinguishable from the human tumour. To our knowledge, this is the first report of a dysembryoplastic neuroepithelial tumour in a zebrafish.

Spontaneous renal lymphosarcoma in a juvenile cynomolgus monkey (Macaca fascicularis)

Spontaneous lymphosarcoma, likely of renal origin, was diagnosed in a naive, juvenile, male cynomolgus monkey (Macaca fascicularis). Histologically, renal architecture was effaced by dense infiltrating sheets of plump cells with indistinct borders and scant amphophilic cytoplasm. Mitoses were uncommon. Similar neoplastic infiltrates were also present in the right renal cortex, one adrenal medulla, the prostate, seminal vesicles, myocardium, and the pulmonary interstitium. Serological tests were negative for infection with Simian Immunodeficiency Virus (SIV), Simian T-Lymphotropic Virus-1 (STLV-1), and Simian Retrovirus-5.

Subclinical lumbar polyradiculopathy, polyneuritis and ganglionitis in aged wild and exotic mammalians

Subclinical lumbar polyradiculopathy was present in the intradural dorsal and ventral nerve rootlets of 19 aged individuals of the following wild and exotic mammalian species: woodrat, raccoon, mink, lynx, reindeer, red deer, musk ox, scimitar-horned oryx, Arabian oryx, hybrid waterbuck, Persian onager, Przewalski's wild horse, Malayan sun bear, Asian elephant, East African river hippopotamus, vervet monkey and rhesus monkey. It was characterized by mild to severe multifocal ballooning of myelin sheaths. Occasionally, ballooned myelin sheaths contained thin strands of myelin and macrophages surrounding distorted axons. Additionally, a mild incidental lymphocytic polyneuritis was present in intradural nerve rootlets of the Malayan sun bear, and a moderate lymphocytic spinal ganglionitis in the East African river hippopotamus.

A fibrosarcoma in the skeletal muscle of a capybara (Hydrochoerus hydrochaeris)

An 8-yr-old male capybara (Hydrochoerus hydrochaeris), a resident of an urban zoological collection in upstate New York (USA), had a mass posteroventral to its left stifle; it was of unknown duration. The mass was a fibrosarcoma based on invasive sheets of interwoven spindle-shaped neoplastic cells with moderate associated extracellular matrix composed of collagen fibers. Supportive immunohistochemical staining was positive for vimentin but negative for cytokeratins, desmin, and myoglobin. The animal subsequently died of unknown causes. This is the first known report of a neoplasm in a capybara.

Microscopic anatomy of the skin of the woodchuck (Marmota monax): comparison of woodchuck hepatitis virus-infected and non-infected animals

Thirty-three woodchucks were used in this study. Seventeen animals were healthy adults, not infected with woodchuck hepatitis virus (WHV); 10 were healthy adults infected with WHV; 4 were noninfected neonates; 2 were infected neonates. Within the 4 groups of woodchucks, no histologic differences were detected on the basis of sex or age. Neither were histologic findings different between infected and noninfected woodchucks of similar ages. The average thickness of skin (as measured from the skin surface to the inner limit of the dermis) from the general haired body area was 2394 microns. The skin was thickest on dorsal body areas, and gradually became thinner on ventral body and medial limb areas. The epidermis consisted of 4 layers: stratum basale, stratum spinosum, stratum granulosum, and stratum corneum. A stratum lucidum was present only in the epidermis of the footpads. There was no clear distinction between the superficial dermis and the deep dermis, except for the subtle differences in arrangement and size of collagen fibers. Elastic fibers were seen throughout the dermis, being more prominent in the superficial portion. Both compound and simple hair follicle arrangements were seen, with compound being more common. The arrectores pilorum muscles were largest in the skin over the dorsal body areas. Sebaceous glands were present either within the outer root sheath of hair follicles or in the dense connective tissue surrounding hair follicles. No apocrine sweat glands were found. However, there were abundant eccrine sweat glands in the subcutaneous fat of the footpads.

Skin disorders of the laboratory woodchuck (Marmota monax): a retrospective study of 113 cases (1980-1990)

An 11-year retrospective study was conducted on the dermatoses occurring in 113 woodchucks from a colony at the College of Veterinary Medicine at Cornell University. Bacterial dermatitis was the most common dermatologic disorder, accounting for 70.2% of the cases. The highest incidence of bacterial dermatitis occurred in September/October prior to hibernation and in February/March during the breeding season. Other dermatoses observed during the study period included Taenia crassiceps infection, microfilarial dermatitis, telogen defluxion, various neoplastic and hyperplastic lesions, and various neonatal conditions associated with trauma and/or bacterial infection. No association was found between any of these dermatoses and the presence of woodchuck hepatitis virus infection.

Immunopathology of glomerulonephritis associated with chronic woodchuck hepatitis virus infection in woodchucks (Marmota monax)

Retrospective analysis of necropsy findings of 705 woodchucks was performed to determine the prevalence and morphology of immune-mediated glomerulonephritis, its relationship to woodchuck hepatitis virus (WHV) infection, and the presence of major WHV antigens. Twenty-six woodchucks had glomerular lesions. Renal tissue of the 26 animals was evaluated histologically and immunohistochemically for immune-mediated glomerulonephritis. Of these 26 animals, immune-mediated glomerulonephritis was diagnosed in six, all of which were chronic WHV carriers. Membranous glomerulonephritis was identified in three animals, two of which also had mesangial proliferation. Host immunoglobulin was present within the mesangium and along capillary loops in all three. Woodchuck hepatitis virus core antigen (WHcAg) was present along capillary loops of two of these animals, one membranous and one mixed, and in the mesangium of all three. Woodchuck hepatitis virus surface antigen (WHsAg) deposition was similar to WHcAg deposition but was only present along capillaries in those animals with mixed nephritis. The remaining three animals had mesangial proliferation. WHsAg and host immunoglobulin deposition were predominately mesangial; WHcAg was not detected. Transmission electron microscopy showed thickening of the capillary loop basement membranes and subepithelial electron-dense deposits in animal one, and deposits in the mesangium in animal six.

Cutaneous trichilemmal cysts in three dogs

Cutaneous trichilemmal cysts were recognized in 3 dogs. The lesions were multiple, asymptomatic, and occurred over the dorsal lumbar, lateral thoracic, dorsal neck, and cranial carpal regions. These cysts were not accompanied by other disease processes, and did not recur following surgical excision. Histologically, the trichilemmal cyst is characterized by trichilemmal differentiation of the entire cyst wall, and the formation of a predominantly amorphous and nonlaminated keratin in the cyst cavity.

Cutaneous hybrid cyst in four dogs

Cutaneous hybrid cysts were recognized in 4 dogs. The lesions were solitary, asymptomatic, and occurred over the head, neck, proximal thigh, and lumbar region. These cysts were not accompanied by other disease processes, and did not recur following surgical excision. Histologically, the hybrid cyst is characterized by epidermal differentiation in its upper portion, and trichilemmal differentiation in its lower portion.

Neoplasms of the apocrine sweat glands in 44 dogs and 10 cats

Neoplasms of the apocrine sweat glands accounted for 2.0 per cent and 3.6 per cent, respectively, of all canine and feline skin neoplasms diagnosed during a period of three years. They occurred in dogs from six to 17 years of age of both sexes, and golden retrievers appeared to be predisposed; they occurred in cats from six to 17 years of age and there were no breed or sex predilections. In both species, the neoplasms were usually solitary and occurred anywhere on the body; they were nearly always carcinomas and histologically were usually of the solid type. There were no clinical measurements that made it possible to distinguish reliably between benign and malignant lesions. No distant metastases were recorded, even though 22.5 per cent of the canine carcinomas had invaded the lymphatic system.

Two rare cutaneous neoplasms in horses: apocrine gland adenocarcinoma and carcinosarcoma

Two rare equine cutaneous neoplasms, an apocrine gland adenocarcinoma and a carcinosarcoma were diagnosed in a 17-year-old pony and a 14-year-old mare, respectively. The apocrine gland adenocarcinoma was present on the prepuce. Histologically, papillary projections of low cuboidal to columnar epithelial cells were generally well differentiated, and surrounded dilated acini. Stromal invasion was present, but vascular and lymphatic invasion was not seen. The carcinosarcoma was present in the right flank of the mare. Two discrete cell populations were characterized histologically. One portion of the mass was composed of elongated, loosely arranged mesenchymatous cells; the second population consisted of dense sheets of pleomorphic, basophilic cells forming irregular acini.

Right dorsal colitis

Moderate to severe ulcerative colitis of the right dorsal colon was diagnosed by necropsy or by exploratory celiotomy and biopsy in 13 horses with a primary clinical complaint of either colic, diarrhea, or weight loss. Clinical signs varied from acute fulminating diarrhea (possibly with fever), colic, dehydration, endotoxic shock and death, to a chronic condition manifested by mild intermittent colic up to several months in duration, and weight loss with or without mild diarrhea. In a large percentage of the horses, those affected had been hypovolemic and received nonsteroidal anti-inflammatory drugs (NSAID) or had received inappropriately high doses of phenylbutazone before the onset of illness. Experimental treatment of two horses with high doses of a phenylbutazone oral paste preparation (6 gm once daily for 5 days) and limitation of their water intake to approximately one half of maintenance requirement (for 5 days) resulted in reproduction of ulcerative colitis involving only the right dorsal colon, which was apparent at necropsy examination 11 and 15 days after initiation of drug use. It was concluded that localized ulcerative lesions in the right dorsal colon may be a previously unreported manifestation of toxicity due to the administration of NSAID.

Infarction of the pons and medulla oblongata caused by arteriolar thrombosis in a horse

Infarction of the pons and rostral medulla secondary to arteriolar thrombosis was documented histologically in a 17-year-old mixed-Arabian female horse. Clinically, the animal experienced a sudden onset of a head tilt and subsequent non-controllable seizures. There was no historical, clinical or histological evidence to suggest the presence of infection of Equine Herpesvirus-1 or the feeding of corn contaminated by Fusarium moniliforme.

Sterile nodular panniculitis in five horses

Sterile nodular panniculitis was diagnosed in 5 horses. Physical abnormalities were predominantly limited to cutaneous changes, consisting of multiple subcutaneous nodules that had a tendency to wax and wane over time and were commonly distributed over the trunk, neck, and proximal portion of the limbs. In each horse, the diagnosis was confirmed by excisional biopsy of a nodule and by exclusion of infective causes of panniculitis on the basis of negative culture results and special stain application to skin specimens. Treatment with immunosuppressive doses of glucocorticoids was curative in 1 horse, was required on a daily or alternate-day schedule in 2 others to keep the skin clear, and had no effect on the disease in the remaining 2 horses.

Besnoitiosis of the reproductive tract of a Blue Duiker (Cephalophus monticola)

A mature male Blue Duiker that had been born in the United States was submitted for necropsy examination following a brief illness. On histologic examination of the reproductive tract several Besnoitia cysts were found in the epididymis, prostate and bulbourethral gland. The lack of an inflammatory response or any negative effect on fertility, based on histologic evaluation and breeding history, is in contrast with the severe orchitis, epididymitis and infertility of besnoitiosis in cattle. This is the first report of an autochthonous infection of Besnoitia in the United States as well as the first report of besnoitiosis in a Blue Duiker.

Pulmonary hamartoma and multiple cardiac anomalies in a Finn-Dorset cross lamb

A case of pulmonary hamartoma was diagnosed in a neonatal, male, Finn-Dorset cross lamb with concurrent cardiac anomalies and palatoschisis. On gross examination, the lungs were markedly enlarged and spongy. Histologically, pulmonary lobules were composed of severely dilated and hyperplastic terminal bronchioles, separated by an abundant connective tissue stroma. Alveoli were generally absent. Other bronchi were hypoplastic and lacked both cartilage and smooth muscle. Both the cranial and caudal vena cavae and the pulmonary veins entered the right atrium. This anomaly has not been previously reported in lambs.

Treatment of right dorsal ulcerative colitis in a horse

Excessive administration of phenylbutazone was associated with development of right dorsal ulcerative colitis. The clinical signs of right dorsal colitis include chronic colic and weight loss. The laboratory abnormalities include panhypoproteinemia and a high WBC count in the abdominal fluid. Medical management of the chronic colic and protein-losing enteropathy associated with the ulcerative lesions in the right dorsal colon and surgical bypass of the right dorsal colon did not result in long-term resolution of clinical signs. Resection of the ulcerated right dorsal colon through a right lateral approach at the 16th rib resulted in resolution of intestinal protein loss and colic. The results of this case suggest that surgical resection of the ulcerated right dorsal colon may be the recommended treatment for right dorsal ulcerative colitis.

Bronchioalveolar carcinoma with renal and hepatic metastases in a degu (Octodon degus)

A primary bronchioloalveolar carcinoma with renal and hepatic metastases was diagnosed in a mature male degu (Octodon degus) that was found dead in a zoological exhibit (Buffalo Zoological Gardens, Buffalo, New York, USA). Grossly, a discrete 0.5 cm diameter nodule was seen in the lung. Smaller, but similar nodules were present scattered in the liver and kidneys. Histologically, nests and sheets of an infiltrating population of cuboidal to low columnar neoplastic epithelial cells partially effaced pulmonary architecture. Vascular invasion was evident. Similar nests and sheets of neoplastic cells were present within the renal cortex and medulla, and a small nest was present within the hepatic parenchyma. This is the first record of this neoplasm in a degu.

Primary glossal squamous-cell carcinoma in a Spanish Cochin hen

A primary glossal squamous-cell carcinoma was diagnosed in an adult Spanish Cochin hen. Grossly, there was locally extensive ulceration of the tongue. Histologically, the submucosa was diffusely infiltrated by islands, nests, and fronds of variably differentiated squamous epithelial cells. Neoplastic cells extended into the underlying muscular layer and stimulated intense scirrhous and inflammatory reactions.

Subclinical lumbar polyradiculopathy in aged domestic, laboratory, and exotic mammalian species--a light and selected electron microscopic study

Lumbar polyradiculopathy, characterized by ballooning myelin sheaths and axonal distortion, was documented in multiple, aged, domestic, laboratory, and exotic mammalian species. Animals studied that exhibited this nerve rootlet change included the goat, sheep, pig, white-tailed deer, gerbil, vole, ferret, beaver, hedgehog, chinchilla, North Chinese leopard, lion, cheetah, mountain lion, llama, East African eland, Uganda giraffe, polar bear, and drill. Ultrastructurally, lumbar nerve rootlets from the North Chinese leopard revealed prominent and often multiple lamellar separations in the area of myelin bubbling. Clefts in myelin sheaths contained macrophages with engulfed fragments of myelin. Axons were sometimes variously attenuated, and the axoplasm contained densely packed neurofilaments. In all species, the lesion was subclinical and considered an incidental age-related finding.

Thyroid follicular carcinoma with pulmonary metastases in a beaver (Castor canadensis)

An 11-yr-old female beaver (Castor canadensis) died after a 3 1/2 mo course of intermittent diarrhea, lethargy and anorexia. A postmortem examination revealed both a necrotizing ulcerative colitis and bilaterally enlarged thyroid glands. Histologically, the necrotizing colitis was similar to that caused by canine or feline parvovirus. Thyroid glands were multilobulated. Lobules were composed of irregularly arranged, variably sized follicles, some of which contained colloid. Follicles were lined by a pleomorphic population of tall cuboidal to columnar epithelial cells. Capsular invasion was present. Similar cells, forming follicles were present within the pulmonary parenchyma. This is the first documented case of a thyroid follicular carcinoma with pulmonary metastases in a beaver.

Cholangiocarcinoma in a 4-month-old double yellow-cheeked Amazon parrot (Amazona autumnalis)

A cholangiocarcinoma was diagnosed in a 4-month-old double yellow-cheeked Amazon parrot (Amazona autumnalis). Histologically, neoplastic cells effaced hepatocellular architecture. Ultrastructurally, variably dilated bile ductules were lined by simple cuboidal to low columnar ciliated epithelial cells with sparse cellular organelles and prominent junctional complexes. Elongated single cilia arising from basal bodies in the apical cytoplasm were occasionally evident. The presence of such a neoplasm in a 4-month-old parrot is extremely unusual.

Presumptive subcutaneous surgical transplantation of a urinary bladder transitional cell carcinoma in a dog

A urinary bladder mass in a 12-year-old spayed female West Highland White Terrier was diagnosed after exploratory surgery and biopsy as a transitional cell carcinoma. Four months later the dog presented with an ulcerated plaque-like cutaneous lesion at the previous surgical incision site; concurrent inguinal lymphadenopathy and recurrence of the urinary bladder mass were identified. Transitional cell carcinoma was diagnosed at all 3 sites. Although a definitive relationship cannot be established between the initial surgery for urinary bladder mass and the resultant subcutaneous lesion, surgical implantation should be considered as a source for the neoplastic cells.

Study of association between histologic features and echogenicity of architecturally normal cat kidneys

Thirty-eight grossly and histologically normal cat kidneys were examined ultrasonographically. The echogenicity of the renal cortex was subjectively evaluated by scoring it as largely or not largely different from the echogenicity of the renal medulla and as similar or not similar to the echogenicity of the renal sinus. The presence or absence of a medullary hyperechoic band was determined. The length, width, and height of each kidney was measured. Hematoxylin and eosin-stained sections of each kidney were examined microscopically. The amount of fat vacuoles in the tubular epithelium of the renal cortex was scored as plentiful or not plentiful. The presence or absence of a medullary band of mineral deposits within the lumina of renal tubules was determined. A plentiful amount of fat vacuoles in renal cortex was associated positively with a large difference in echogenicity between cortex and medulla (P less than 0.01) and with similar echogenicity of cortex and sinus (P less than 0.01). The presence of a medullary hyperechoic band was associated positively with a band of mineral deposits within medullary tubular lumen (P 0.01). Kidneys with a large difference in echogenicity between cortex and medulla and kidneys with a plentiful amount of fat vacuoles were not significantly different in size (P = 0.56). These groups were larger (P less than 0.01) in length, width, and height than were kidneys without a large difference in echogenicity between cortex and medulla and kidneys that did not have plentiful cortical fat vacuoles.

Multifocal bullous emphysema with concurrent bronchial hypoplasia in two aged Afghan hounds

Multiple scattered foci of bullous emphysema were detected in the lungs of two aged Afghan Hounds. The affected parenchyma contained bronchi with rudimentary cartilage and small smooth muscle bundles. The bronchi were generally lined by cuboidal epithelium. The animals were generally asymptomatic throughout their entire lives. One, the female, developed dyspnoea and tachypnoea terminally, following the rupture of two bullae.

The ultrastructural effect of amprolium medication on development of Eimeria adenoeides in turkeys

The ultrastructural appearance of first-generation schizonts of Eimeria adenoeides was markedly altered in turkey poults fed 0.0125% amprolium-medicated feed. When compared with development seen in unmedicated control birds 48-72 hr postinoculation (PI), most of the schizonts present in the medicated birds were fragmented, contained enlarged nuclei, had swollen endoplasmic reticulum and Golgi apparatus, and showed no budding of merozoites. Other schizonts were almost completely degenerated and contained pyknotic nuclei, dense cytoplasm, and large intracytoplasmic vacuoles containing membrane whorls or lipid droplets. A few mature schizonts were seen in the medicated poults, and these did not appear to differ ultrastructurally from those seen in unmedicated control birds. Ultrastructurally normal second-generation schizonts and the sexual stages were also seen in small numbers in the medicated turkey poults 72-120 hr PI. Mature sexual stages were seen much earlier in medicated turkeys--at 96 hr PI--than in the unmedicated poults.

Eurytrema procyonis in a raccoon (Procyon lotor) from New York state--a first report

The digenean, Eurytrema procyonis, found in the pancreatic ducts of the raccoon (Procyon lotor), is reported for the first time from a juvenile female raccoon captured in July 1987, in New York State (USA). The presence of greater than 183 trematodes in the pancreatic ducts was an incidental finding at necropsy to an interstitial pneumonia which had caused emaciation, and for which the animal was euthanized. The pancreas, with the exception of the major pancreatic duct, was histologically normal. The duct, containing the parasites, was dilated and contained a diffuse subepithelial inflammatory infiltrate consisting primarily of eosinophils. Epithelial hyperplasia was present in tubulo-alveolar glands, and goblet cells were prominent.

Idiopathic benign lichenoid keratosis on the pinna of the ear in four dogs

Histologically, multiple wart-like papules or hyperkeratotic plaques on the ear pinnae from 4 dogs were characterized as idiopathic benign lichenoid keratosis. Common histologic features included a discrete lesion of irregular and papillated epidermal hyperplasia with a moderate diffuse lichenoid interface inflammatory infiltrate consisting of lymphocytes and plasma cells. There was also focal hydropic degeneration of the epidermal basal cell layer, pigmentary incontinence, and mixed orthokeratotic and parakeratotic hyperkeratosis. In all 4 dogs, the pinnal lesions were unilateral and asymptomatic. Complete surgical excision was curative.

Cartilaginous metaplasia associated with a basal cell tumour in a dog

Locally extensive dermal cartilaginous metaplasia was seen in association with a pigmented basal cell tumour in an aged, spayed Basenji dog. Six months after surgical excision, the animal remains healthy with no recurrence of the neoplasm.

Renal dysplasia in a pig

A diagnosis of renal dysplasia was made in a six-month-old, male, mixed-breed pig. Both kidneys were small, firm, slightly pitted, and contained an indistinct corticomedullary junction. Histologically, primitive tubules were present surrounded by an abundant loose, mesenchymatous stroma. Occasionally, tubules were markedly dilated and lined by a pseudostratified columnar epithelium forming epithelial mats that obscured the lumina. Immature glomeruli were present. Multifocal glomerular sclerosis was evident. Other mature glomeruli were enlarged and characterized by mesangial cell hyperplasia forming an arborizing pattern.

Acute pelvic limb paralysis induced by a lumbar fibrocartilaginous embolism in a sow

A diagnosis of fibrocartilaginous embolism was made in a mature mixed-breed sow with a history of an acute onset of pelvic limb paralysis. Within a single section of lumbar spinal cord, there was severe focally-extensive infarction of the right ventral gray horn. Within affected white matter, there was dilatation of multiple myelin sheaths with concurrent axonal swelling. A smaller focus of infarction was present on the contralateral side. Arteries at the periphery of both lesions contained a blue-gray material with staining characteristics similar to that evidenced by the nucleus pulposus present within intervertebral discs. Grossly, no abnormalities were present within the vertebral column.

Incomplete subaortic stenotic rings in domestic animals--a newly described congenital anomaly

A newly described congenital heart anomaly, the incomplete subaortic stenotic ring was detected at necropsy in four dogs, one cat, one cow, one horse, one sheep and one pig. These structures were grossly and histologically similar to complete subaortic stenotic rings, being composed of variably dense interlacing bands and sheets of fibrous connective tissue. In all nine cases, their presence at necropsy was considered an incidental finding.

Neoplastic angioendotheliomatosis in a dog: an angiotropic lymphoma

Neoplastic angioendotheliomatosis was diagnosed in a nine-year-old, intact male German Shorthaired Pointer exhibiting progressive neurological signs over a six-month period. At necropsy, there was multifocal asymmetric, hemorrhagic necrosis within the cerebral hemispheres, centrum semiovale, caudate nucleus, and internal capsule. Histologically, there was extensive intravascular proliferation of pleomorphic mononuclear cells within the brain and multiple parenchymatous organs. Transmission electron microscopy demonstrated the absence of intercellular junctions between neoplastic cells. These cells were not attached to the vascular lining endothelium; Weibel-Palade bodies and a basement membrane were lacking. By indirect immunofluorescence, positive cytoplasmic staining of intravascular neoplastic cells for IgG was demonstrated. Peroxidase-antiperoxidase technique for Factor VIII related antigen was negative. As in man, this rare neoplastic disorder appears to be a lymphoma, apparently of the B cell line.

Subclinical lumbar polyradiculopathy in multiple aged mammalian species

Lumbar polyradiculopathy, characterized by ballooning myelin sheaths was diagnosed in multiple aged mammalian species including two horses, a cow, a squirrel, a woodchuck, a rabbit, a guinea pig, a hamster, and a mouse. The lesion was subclinical, and considered an incidental, age-related finding.