Design of a simplified histopathologic model for gastrointestinal inflammation in dogs.

Significant interobserver variability in the diagnostic interpretation of endoscopic gastrointestinal (GI) specimens exists even with the use of World Small Animal Veterinary Association (WSAVA) standardization criteria. Chi-square analyses compared the extent of pathologists' agreement for microarchitectural features of inflammation in endoscopic specimens obtained from 253 animals of the original WSAVA study. Patterns of agreement between pathologists were classified as broad (3/4 pathologists agreed), dichotomous (2/4 pathologists agreed), or divergent (no agreement between pathologists). The simplified model for GI inflammation was based on those parameters for which the pathologists had either broad or minimally divergent opinions of histopathologic significance. In this model, the parameters chosen were as follows: gastric parameters (intraepithelial lymphocytes [IELs], lamina propria [LP] infiltrates, and mucosal fibrosis), duodenal parameters (villus atrophy, epithelial injury, IELs, crypt changes, and LP infiltrates), and colonic parameters (epithelial injury, crypt dilation, fibrosis, LP infiltrates, and goblet cell depletion). Preliminary data using this simplified model showed excellent correlation between pathologists in defining the presence and extent of GI inflammation in dogs.

Effect of tissue processing on assessment of endoscopic intestinal biopsies in dogs and cats.

BACKGROUND: Prior studies failed to detect significant association between hypoalbuminemia and small intestinal lesions. HYPOTHESIS: Use of pictorial templates will enhance consistency of interpathologist interpretation and identification of intestinal lesions associated with hypoalbuminemia. ANIMALS: Tissues from 62 dogs and 25 cats examined as clinical cases at 7 referral veterinary practices in 4 countries. METHODS: Retrospective, observational study. Histopathology slides from sequential cases undergoing endoscopic biopsy were examined by 4 pathologists by pictorial templates. Changes for 9 microscopic features were recorded as normal, mild, moderate or severe, and 2- and 4-point scales were tested for consistency of interpretation. Logistic regression models determined odds ratios (OR) of histologic lesions being associated with hypoalbuminemia while kappa statistics determined agreement between pathologists on histologic lesions. RESULTS: There was poor agreement (kappa = -0.013 to 0.3) between pathologists, and institution of origin of slides had effect (kappa = 1.0 for 3 of 4 lesions on slides from Institution 5) on agreement between pathologists on selected histologic features. Using 2 point as opposed to 4-point grading scale increased agreement between pathologists (maximum kappa = 0.69 using 4-point scale versus maximum kappa = 1.0 using 2-point scale). Significant association (P = .019- .04; 95% OR = 3.14-10.84) between lacteal dilation and hypoalbuminemia was found by 3 pathologists. CONCLUSIONS AND CLINICAL IMPORTANCE: Substantial inconsistency between pathologists remains despite use of pictorial template because of differences in slide processing. Distinguishing between mild and moderate lesions might be important source of the disagreement among pathologists.

Histopathological standards for the diagnosis of gastrointestinal inflammation in endoscopic biopsy samples from the dog and cat: a report from the World Small Animal Veterinary Association Gastrointestinal Standardization Group.

The characterization of inflammatory change in endoscopic biopsy samples of the gastrointestinal mucosa is an increasingly important component in the diagnosis and management of canine and feline gastrointestinal disease. Interpretation has hitherto been limited by the lack of standard criteria that define morphological and inflammatory features, and the absence of such standardization has made it difficult, if not impossible, to compare results of retrospective or prospective studies. The World Small Animal Veterinary Association (WSAVA) Gastrointestinal Standardization Group was established, in part, to develop endoscopic and microscopical standards in small animal gastroenterology. This monograph presents a standardized pictorial and textual template of the major histopathological changes that occur in inflammatory disease of the canine and feline gastric body, gastric antrum, duodenum and colon. Additionally, a series of standard histopathological reporting forms is proposed, to encourage evaluation of biopsy samples in a systematic fashion. The Standardization Group believes that the international acceptance of these standard templates will advance the study of gastrointestinal disease in individual small companion animals as well as investigations that compare populations of animals.

Development and evaluation of an endoscopic technique permitting rapid visualization of the cardiac region of the porcine stomach.

Our study was designed to ascertain whether a flexible videoscope could be used to efficiently monitor ulcers of the pars esophagea in a large group of grower-finisher swine. Gastroscopy was performed on 2 separate occasions in 32 pigs following anesthesia with intravenous pentobarbital, and ulcers of the pars esophagea were subjectively graded. The pigs were then necropsied. Grades from the second endoscopic examination were compared for agreement with grades derived from gross inspection of the pars esophagea at necropsy, and with grades derived from histopathologic examination of sections of the same region. The pars esophagea was adequately visualized in all endoscopic examinations. The average duration of each examination, from anesthetic induction, was approximately 8 min. Gastroscopy permitted appreciation of a wide range of focal and diffuse superficial and deep ulcerative lesions of the pars esophagea, but failed to unequivocally identify parakeratosis of the pars esophagea. Agreement between endoscopic and subsequent necroscopic and histopathologic gradings of ulcerations was poor. We concluded that the use of a flexible videoscope permitted rapid inspection of the pars esophagea, and was therefore a practical method of experimentally monitoring the progression of spontaneous gastric ulcers in pigs. We also postulated that the poor agreement between endoscopic and postmortem findings occurred because endoscopy was possibly more sensitive at detecting small and superficial ulcerations. However, further studies are needed to verify the accuracy of endoscopic diagnosis of gastric ulcers in the live pig.

Compound odontoma in a dog.

Compound odontomas are rare tumors of dental origin. Though benign, their effect as a space occupying lesion can be dramatic. A large compound odontoma in the caudal right mandible of a five and a half month old dog was managed by surgical enucleation of the abnormal tissues. No recurrence was evident 6 months later.

The causes of glaucoma in cats.

The cause of glaucoma in 131 enucleated eyes from 128 cats was determined in a retrospective histologic study. Obliteration of the ciliary cleft by diffuse iridal melanoma (38 eyes), or other neoplasms (14 eyes), or by the presence of idiopathic lymphocytic-plasmacytic anterior uveitis (53 eyes) were the most frequent lesions likely to explain the development of glaucoma. Secondary changes of inner retinal atrophy, optic disc cupping, scleral thinning with megaglobus, and atrophy of ciliary processes were similar to those described in dogs and human beings with chronic glaucoma. In light of the duration and severity of the glaucoma, the degree of inner retinal atrophy was often less than expected. Diffuse corneal edema and breaks in Descemet's membrane, changes typical of glaucoma in other species, were rarely detected. Eyes with chronic uveitis and glaucoma had collapsed ciliary clefts, iridoscleral adhesions, and posterior displacement of the iris. We were unable to determine whether these changes were consequences of the uveitis and thus responsible for the development of glaucoma, or if they were merely the result of the chronic glaucoma itself.

The pathogenesis and significance of pre-iridal fibrovascular membrane in domestic animals.

Histologic examination was made of 1,419 globes from domestic animals (964 dogs, 374 cats, 41 horses, and 40 cattle) with ocular disease; pre-iridal membranes (rubeosis iridis) were found in 98. The membranes originated as endothelial budding from the anterior iridal stroma and seemed to mature into fibrous or fibrovascular membranes that were often followed by hyphema or, occasionally, glaucoma. Pre-existent disease in the 98 affected globes included chronic endophthalmitis (27/98), chronic glaucoma (24/98), anterior uveal melanoma (15/98), ciliary body adenoma (14/98), neoplasms metastatic to the eye (8/98), and chronic retinal detachment (6/98). In terms of likelihood of occurrence, pre-iridal membranes seen in 21% (6/21) of globes with retinal detachment, 19% (14/75) of those with ciliary body adenomas, 14% (24/167) of those with chronic glaucoma, and 10% (15/158) of those with anterior uveal melanoma. They were detected with greatest relative frequency in horses (9/41) followed by dogs (83/964), cats (5/374) and cattle (1/40). These membranes, which are rarely detected by clinical examination, probably form in response to angiogenic factors released by ischemic retina, by neoplasms, or by leukocytes involved in ocular inflammation.

Cerebrospinal fluid analysis and clinical outcome of eight dogs with eosinophilic meningoencephalomyelitis.

Eight dogs, 14 weeks to 5.5 years of age, had signs of diffuse or multifocal meningoencephalomyelitis. The total white cell counts of the cerebrospinal fluid (CSF) ranged from 11 to 5,550 cells/microliters; the percentage of eosinophils ranged from 21% to 98%. The total CSF protein content range was 19 to 1,430 mg/dl. On necropsy, two dogs had granulomatous encephalomyelitis due to protozoan infection. The other six dogs, of which three were Golden Retriever dogs, appeared to have an idiopathic eosinophilic meningoencephalitis; four of these dogs recovered. The significance of eosinophils in CSF and the possible emergence of a new encephalitic syndrome of dogs involving a hypersensitivity to an unknown agent is also discussed.

Adenocarcinoma of the gland of the third eyelid in seven dogs.

Adenocarcinoma of the gland of the third eyelid developed as a smooth, pink nodule on the bulbar aspect of the third eyelid of seven 10- to 16-year-old dogs. Tumors recurred in 4 dogs. One dog, which initially had the most infiltrative-appearing tumor among those studied, was euthanatized 7 months after the first excision, because of extensive local recurrence and suspected metastasis. Tumors did not recur after removal of the entire third eyelid as the initial or follow-up procedure. We recommend removal of the entire third eyelid to prevent local recurrence of the tumor.

The pathology of lens-induced uveitis in dogs.

Rupture of the lens capsule in 20 dogs resulted in zonal, perilenticular inflammation that did not respond to symptomatic therapy and resulted in the loss of the globe. The reaction was dominated by lens epithelial proliferation, pupillary occlusion, and glaucoma in 11 of the 20. This reaction, herein named phacoclastic uveitis, is unique and easily distinguished from the mild lymphocytic-plasmacytic anterior uveitis that accompanies leakage of lens material through an intact capsule of a hypermature cataract (phacolytic uveitis). None of the dog eyes had the granulomatous perilenticular inflammation that is the hallmark of lens-induced (phacoanaphylactic) uveitis in humans.

Glioma of the optic nerve with intraocular and intracranial involvement in a dog.

An anaplastic glioma of the optic nerve, involving the globe, optic chiasma and brain in a 3 1/2-year-old Labrador Retriever is described. The tumour consisted of lobules of small, dark cells intersected by a delicate fibrovascular stroma. There was a high degree of anaplasia and an average of 19 mitoses per x 200 field. The clinical signs were exophthalmos and mydriasis, followed several months later by blindness and, only terminally, by signs of brain involvement.

Morphology and behavior of primary ocular melanomas in 91 dogs.

Primary ocular melanocytic neoplasms from 91 dogs were divided into two groups by histologic criteria. Seventy-five were benign and composed of spindle-shaped and large polyhedral melanocytes similar to those of human ocular melanocytomas. Fifty-nine of these originated in the uvea where most resulted in uveitis, glaucoma, or hyphema prior to enucleation. None metastasized. Nineteen melanocytomas were limbal tumors. None metastasized, but three of nine incompletely excised tumors were found within the anterior chamber 2 to 3 years after the initial removal. Sixteen uveal melanocytic neoplasms were histologically malignant. Three had confirmed metastases, all within 3 months of enucleation. Cell type or pattern of growth within the globe were not predictive of biologic behavior. Our data suggest that the mitotic index is the best criterion for histologic identification of ocular melanomas with high metastatic potential. We propose that the classification of primary ocular melanomas be simplified to include only two categories: melanocytoma (benign) and melanoma (potentially malignant). Further behavioral data may justify a grading scheme for melanomas based upon mitotic index.

The morphology and behavior of feline cutaneous mastocytomas.

Correlation of histopathology with the behavior of cutaneous mastocytomas in 85 cats revealed two distinct histologic subtypes which were predictive of biologic behavior. The first subtype comprised 65 cats of various breeds which had solitary, discrete, dermal tumors composed of slightly atypical mast cells. Most tumors in this group were histologically and behaviorally benign. However, seven solitary tumors with marked anisocytosis and mitotic activity recurred or spread to other sites within 2 to 3 months. The second subtype occurred in 18 cats which had discrete subcutaneous nodules composed primarily of histiocyte-like cells with equivocal cytoplasmic granularity after staining with toluidine blue. They were identified as mast cells by electron microscopy. Seventeen of the 18 affected cats were Siamese. The histiocytic mastocytomas occurred predominantly in young cats (less than 4 years) and were usually multiple. In the four cats of this group for which we have prolonged follow-up data, the tumors underwent apparently spontaneous regression within 2 years of initial tumor detection. Two other cats had tumors which contained mixtures of mast cell and histiocytic morphologies.

Mycetoma-like granuloma in a cat caused by Microsporum canis.

A solitary subcutaneous nodule from a Persian cat consisted of coalescing mycetoma-like granulomas containing abnormal hyphae of Microsporum canis. Overlying hair follicles were heavily laden with dermatophytes but had little associated perifollicular inflammation. The complex classification of dermatophyte-induced dermal inflammatory lesions is reviewed.

Neurologic disease in naturally occurring Salmonella choleraesuis infection in pigs.

A granulomatous meningoencephalomyelitis was seen in 17 feeder pigs submitted for diagnostic evaluation from eight farms. Vasculitis and destructive microgranulomas were widespread in both brain and spinal cord. Occasionally there were microabscesses. Salmonella choleraesuis var. kunzendorf was isolated from six of the eight groups, and there were lesions of acute salmonellosis in all animals examined. In three of the affected herds the principal disease manifestation was neurologic.