Cutaneous lesions.

Although not a substitute for histologic examination, lumps, bumps, and lesions of the skin and subcutis readily lend themselves to cytologic examination via FNB, fine-needle nonaspiration biopsy, imprinting, or scraping of lesions. These techniques are used to obtain cells that can be examined by a clinical pathologist or cytologist to provide a diagnosis, decide a course of therapy, or offer a prognosis. Although histologic and cytologic examinations do not always agree, many times there is excellent correlation between the two disciplines. There are few patients with cutaneous lesions that would not benefit from cytologic examination of their lesion.     

Bovine nasal granuloma. Gross and microscopic lesions.

The anterior nasal mucosa of 21 cattle had small closely-packed polypoid nodules. These had a distribution pattern similar to that of inhaled particles. Acute inflammatory changes consisting of eosinophil infiltration, mast cell and globule leucocyte hyperplasia, and oedema were frequent in the epithelium, terminal gland ducts and adjacent lamina propria. Epithelium over nodules was metaplastic to non-keratinising stratified squamous, whilst epithelium of terminal gland ducts was metaplastic to mucus-secreting pseudostratified columnar. Focal accumulation of granulation tissue between gland ducts caused herniations of the superficial lamina propria to form the nodules.     

Gross and histopathological findings in unusual lesions caused by Streptococcus suis in pigs. I. Cardiac lesions.

Unusual lesions caused by Streptococcus suis involved the heart of 48 pigs necropsied over a four-year period. Lesions included fibrinopurulent pericarditis (six pigs), hemorrhagic, necrotizing myocarditis resembling mulberry heart disease (21 pigs), and vegetative valvular endocarditis (21 pigs). Histologically, the myocarditis was characterized by focally extensive and diffuse hemorrhages and necrosis, with infiltrations of neutrophils and mononuclear cells, and thrombosis of small and large myocardial vessels. The 21 pigs with vegetative valvular endocarditis generally were over ten weeks old and had died suddenly. The left atrioventricular valve was affected in 18 hearts. Most of an affected valve was replaced by a layer of granulation tissue covered by a mixture of fibrin, inflammatory cells, necrotic debris and large numbers of coccoid bacteria.     

Gross and histopathological findings in unusual lesions caused by Streptococcus suis in pigs. II. Central nervous system lesions.

Subacute meningoencephalitis or meningoencephalomyelitis caused by Streptococcus suis was diagnosed in 53 pigs over a four-year period. Affected pigs averaging 11 weeks of age with a range from five days to 26 weeks, had been treated with antibiotics and had partially recovered. Hyperemia of meningeal vessels and modest increase in cerebrospinal fluid were the most common gross central nervous system lesions. Histologically, fibrin, edema and a mixture of inflammatory cells were present in meninges and choroid plexus. Linear and perivascular infiltrates of neutrophils and mononuclear inflammatory cells invaded the brain and spinal cord and similar infiltrates were in lumina of ventricles and the spinal canal. Inflammatory cells also invaded the superficial layers of the brain directly from the overlying meninges. Bilateral subacute optic perineuritis and Gasserian ganglioneuritis also occurred. Segmental cortical necrosis of cerebellar folia characterized by degeneration, necrosis, neuronophagia and drop out of groups of Purkinje cells was a distinct lesion seen in 27 of the 53 pigs. Mild spongiosis of white matter in the cerebellum and brain stem accompanied these changes.     

Feline dental resorptive lesions. Prevalence patterns.

Surveys were carried out in cats presented for dental examination in the Netherlands (432 cats) and in the United States (78 cats). In 62% of the Dutch cats and 67% of the US cats, resorptive lesions were present. In the Dutch study, Asian Short-hair (principally Siamese) cats were most commonly involved, and male cats were more commonly affected than females. The most commonly affected teeth were the fourth maxillary premolar and the mandibular premolar and molar teeth.     

Neuromuscular lesions in restrained rabbits.

Ten of 16 rabbits restrained 6 h daily for 35 days developed focal to diffuse degeneration of the sciatic nerves. Very small necrotic areas also were found in the skeletal muscles of seven of 16 rabbits, but the muscle lesions did not correlate with the nerve changes.     

Ultrasonographic evaluation of back lesions.

With progressive advances in ultrasonographic equipment, evaluation of a number of axial skeletal structures is now possible. Ultrasonography is presently the best technique for evaluation of the SSpL and lumbosacral intervertebral discs. It is a useful adjunct to radiography for assessment of spinous processes and AP injuries.     

Ovarian tumors and related lesions in aged chimpanzees.

The ovaries of a 48-year-old chimpanzee each contained a large bilateral fibrothecoma. A 39-year-old chimpanzee had two small fibrothecomas in one ovary and a well-differentiated Sertoli-Leydig cell tumor in the other; there also was adenomatous hyperplasia of the endometrium. Both animals had extensive thecal hypertrophy in the ovaries. Thecal hypertrophy might have been a source of excessive estrogen and could have been a partial cause of the ovarian tumors.     

Liquoid-induced arterial lesions and the generalized Shartzman reaction.

Mural necrotic lesions were produced in renal afferent arteries in rabbits, pigs and blue foxes, by intravenous injections of Liquoid. These lesions were frequently accompanied by thrombosis in the affected arterial segments and invariably by “microthrombosis” in glomerular capillaries. Mural arterial lesions were always present in cases with evident macroscopic necrotic changes of the renal cortex. Necrotic arterial lesions, with thrombosis, were also observed in pulmonary arteries in all the animal species used in these experiments, i.e. rabbit, pig, blue fox, mouse and ferret.     

Canine distemper with spinal cord lesions.

A case of distemper in a 6-month-old dog is described. The dog was presented with a history of tetraparesis suggestive of trauma. Neurological examination and clinical pathology findings of lymphopenia and pleocytosis suggested a viral cause. Microscopic findings of a nonsuppurative meningoencephalomyelitis with numerous intranuclear inclusions in the cerebellum, brain stem, and all parts of the spinal cord suggested a diagnosis of distemper.     

Poxlike skin lesions in captive caimans.

Three juvenile captive spectacled caimans (Caiman sclerops) had scattered, gray-white, circular, 1- to 3-mm skin lesions. In one caiman, the lesions were particularly prominent on the phalanges, palpebrae, and integument overlying the maxillae and mandible. Digital biopsy revealed large eosinophilic intracytoplasmic inclusions within epithelial cells. Transmission electron microscopy of lesions from the lower jaw revealed viral particles morphologically similar to poxvirus.     

Etiopathogenesis of feline dental resorptive lesions.

There are several factors in the etiopathology of feline resorptive lesions. They may be considered as local immune-response mediating cell and humoral factors; release of biochemical components in dental and paradental tissues to attract odontoclasts; mechanical stress, including occlusal mechanism; and local and systemic calcium regulation, including remodeling of mineralized tissue and dietary intake of calcium.     

Poult malabsorption syndrome. II. Pathogenesis of skeletal lesions.

One-day-old poults were placed on litter on which poults had previously developed diarrhea, increased mortality, stunting, and malabsorption. Gross, microscopic, and morphometric evaluations of the proximal tibiotarsal growth plate, along with analysis of plasma calcium, phosphorus, and 25-hydroxyvitamin D3 concentrations, were conducted for 3 weeks to determine the development and character of skeletal lesions. Poults developed enteritis with diarrhea and dehydration. Body weights and shank lengths were significantly decreased. Plasma 25-hydroxyvitamin D3 concentrations were significantly decreased. Plasma calcium was significantly decreased on day 8. Plasma phosphorus concentrations were significantly increased on day 8 and were significantly decreased on days 15, 18, and 22. Growth plates narrowed on days 8 and 11 and expanded on days 15, 18, and 22. The proliferating-prehypertrophy zone significantly decreased in length on days 11, 18, and 22, and significantly increased in length on day 15. The unmineralized hypertrophy zone was significantly increased in length on days 15, 18, and 22. The mineralized hypertrophy zone was significantly decreased in length on all days. Skeletal lesions during the poult malabsorption syndrome evolved from an early osteoporotic lesion associated with hypocalcemia to a rachitic lesion associated with depleted vitamin D and hypophosphatemia.     

Oral surgery. Radical resection of maxillary and mandibular lesions

The results obtained following both maxillectomy and mandibulectomy in animals with benign disease show that these procedures are practical. The challenge is to select those animals with malignant disease where the disease is sufficiently localized so that radical resection will be curative, or where residual disease can be controlled by adjuvant therapy. The series of cases reported in Tables 1 and 2 represent animals treated during the "developmental phase" of these procedures. With 5 years of case experience now available, the usefulness and limitations of these procedures are becoming clearer.     

Placental lesions in habitually aborting cats.

An ovariohysterectomy was done on five female cats with a history of habitual abortion in the 3rd to 4th week of pregnancy and the foetuses and placentas examined. Histologic and electron microscopic examination showed multifocal placental necrosis which was deduced to begin in the syncytial trophoblastic cells and to extend to all the cells of the labyrinth. This lesion was followed by foetal autolysis. No bacterial, viral or mycoplasmal agents could be incriminated in the disease.