A retrospective study of cases of a unique intramural inflammatory mass within the feline gastrointestinal tract was performed in order to describe and characterize the lesion. Twenty-five cases were identified from archival surgical and postmortem tissues. The lesion most often occurred as an ulcerated intramural mass at the pyloric sphincter (n = 12) or the ileocecocolic junction or colon (n = 9); the remaining cases were in the small intestine. Seven cases also had lymph node involvement. The lesions were characterized by eosinophilic inflammation, large reactive fibroblasts, and trabeculae of dense collagen. Intralesional bacteria were identified in 56% of the cases overall and all of the ileocecocolic junction and colon lesions. Fifty-eight percent of cats tested had peripheral eosinophilia. Cats treated with prednisone had a significantly longer survival time than those receiving other treatments. We propose that this is a unique fibroblastic response of the feline gastrointestinal tract to eosinophilic inflammation that in some cases is associated with bacteria. The lesion is often grossly and sometimes histologically mistaken for neoplasia.

Clinical and pathologic features of primary orbital meningiomas in the dog were reviewed. Twenty‐two meningiomas, confined to the orbit, were identified from the Comparative Ophthalmic Pathology Laboratory of Wisconsin from 1981 to 1997. The dogs ranged in age from 3 to 17 years (mean = 9.2 years). The clinical presentation, reported in 20 cases, was indicative of a retrobulbar mass and included exophthalmos and orbital swelling (18/20), and papilledema or abnormalities of the posterior segment (7/20). Visual acuity was reported in 15 cases; of those, 12 dogs were blind in the affected eye. Follow‐up information was obtained on 17 cases; six dogs developed local recurrence of the neoplasm. Two dogs with recurrent neoplasms simultaneously developed blindness in the opposite eye. Extension along the optic nerve to the optic chiasm was suspected. No metastasis was found at the time of the study. Enucleation with excisional biopsy was effective therapy to date in 11 cases (0.2–4.5 years follow‐up time). All neoplasms were located within the vicinity of the optic nerve and, when sectioned through the optic nerve head, appeared to completely envelope the nerve. The neoplastic cells were arranged in tight whorls and bundles characteristic of meningiomas. Most tumors had islands of chondroid and osseous metaplasia (17/22). Ocular invasion was limited to small foci in the posterior choroid or optic nerve head of six dogs. Immunoperoxidase stains on 10 cases were positive for vimentin and S‐100, but negative for cytokeratin. Electron microscopy revealed complex interdigitations between cell membranes and few desmosomal intercellular attachments. Primary orbital meningiomas have a characteristic histologic appearance and may recur locally after surgical excision.

Abstract. Idiopathic cutaneous and renal glomerular vasculopathy (CRGV) (Alabama rot) is a potentially fatal disease of unknown etiology that affects the skin and kidneys of racing-and training-age Greyhounds. Ultrastructural examinations were performed on two healthy control Greyhounds and 1 2 Greyhounds diagnosed with CRGV based on the presence of characteristic, well-demarcated cutaneous ulcers of the extremities (1 2/ 12), thrombocytopenia (<200,000 plateletddl) (1 2/12), and acute renal insufficiency (BUN > 40 mg/dl, serum creatinine > 2.0 mg/dl) (7/ 12). Early glomerular ultrastructural changes included endothelial swelling, detachment, and necrosis; membranous whorl formation; and platelet adhesion and aggregation. Some capillaries were occluded with aggregated platelets, cellular fragments, and fibrin. Later changes included narrowing of capillary lumina and thickening of glomerular capillary walls by subendothelial accumulation of flocculent, amorphous, variable electron-dense material and occasionally erythrocytes, cellular processes, and fibrin. Glomerular endothelial cells were increased in number and plump, with villouslike cytoplasmic projections. Mesangial cell cytoplasmic processes occasionally were interposed between the endothelium and the basement membrane. No etiologic agents or electron-dense deposits typical of immune complexes were observed. Although the specific etiology was not determined, the ultrastructural changes suggest that glomerular endothelial damage is an important early event in the pathogenesis of CRGV.

Acute pelvic limb paralysis occurred in a racing Greyhound after a traumatic incident. During myelography, a dorsal laceration of the dura mater was detected at T,,,,. Immediate hemilaminectomy was performed at TlL13, but neurologic status did not improve. At necropsy there was epidural and subdural hemorrhage at the T,,,, interspace, and malacia and swelling of the spinal cord at that level. Intramedullary hemorrhage, malacia, and free fibrocartilaginous material characterized histopathology of the lesion. Possible mechanisms of the traumatic disk extrusion are discussed.

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