Interobserver variation among histopathologic evaluations of intestinal tissues from dogs and cats

Agreement among surgical pathologists evaluating routine histologic sections of digits amputated from cats and dogs

Agreement among pathologists interpreting histologic specimens is an area of interest within human pathology, but little work in this area has been reported in the veterinary literature. Agreement among pathologists evaluating routine histologic sections of amputated digits from cats and dogs submitted to multiple diagnostic centers was examined. Histologic sections from surgical specimens were reviewed in a blinded fashion by two pathologists, and a comparison to the original diagnosis, as stated in the diagnostic report, was recorded. A total of 513 cases were reviewed, and complete agreement was reached in 409 (79.7%). Of the 104 instances of disagreement, 77 (74.0%) were considered to be of clinical significance. The diagnosis of keratoacanthoma was disagreed with in 19 of 21 diagnoses (90.4%). No other individual diagnosis was similarly disputed. The overall level of disagreement is large and is similar to that reported in human pathology and suggests that further study of this issue would be useful in veterinary pathology.

Maximizing the diagnostic value of cytology in small animal practice

Cytology is a valuable diagnostic tool in veterinary medicine. A review of the literature indicates its utility in evaluation of specific lesions. The information obtained from cytology is greatly enhanced by a good understanding of its advantages and disadvantages and an open and interactive relationship between clinicians and pathologists. Critical selection of appropriate lesions, good sampling technique, quality sample handling, and provision of a complete clinical history and lesion description enhance the utility of the information returned to the clinician by the pathologist. A good cytologic diagnosis is a team effort.

ULTRASONOGRAPHIC INTESTINAL HYPERECHOIC MUCOSAL STRIATIONS IN DOGS ARE ASSOCIATED WITH LACTEAL DILATION

In this retrospective study, the medical records of 23 dogs with the sonographic feature of small intestinal hyperechoic mucosal striations and an endoscopic or surgical intestinal biopsy were reviewed. Histopathologic lacteal dilation was present in 96% of dogs with mucosal striations. Sonographic findings associated with mucosal striations included: mild jejunal wall thickening (96%), mild duodenal wall thickening (78%), mucosal speckles (70%), and abdominal effusion (87%). The mucosal striations were diffuse (70%) or multifocal (30%) and did not cause loss of wall layering, except in one dog with a severe mural lipogranuloma. Mesenteric lymphadenopathy was identified in 9% of dogs. Thirteen dogs with endoscopic biopsies had mild to moderate villus lacteal dilation and the nine dogs with surgical biopsies had moderate to severe dilation. Inflammatory infiltrates were mild (61%) or moderate (30%) with variable numbers and combinations of cells, including eosinophils (65%), plasma cells (61%), lymphocytes (57%), and neutrophils (30%); one dog had disseminated villus histiocytic sarcoma. The biochemistry changes and clinical signs were consistent with protein-losing enteropathy in 78% of dogs. Hyperechoic mucosal striations in dogs are associated with lacteal dilation and are frequently associated with mucosal inflammation and protein losing enteropathy.

Comparison of endoscopic and full-thickness biopsy specimens for diagnosis of inflammatory bowel disease and alimentary tract lymphoma in cats

OBJECTIVE

To evaluate the accuracy of endoscopic biopsy (EB) specimens for diagnosis of alimentary tract lymphosarcoma in cats.

DESIGN

Prospective study.

ANIMALS

22 cats with inflammatory bowel disease (IBD) or alimentary tract lymphosarcoma.

PROCEDURES

Endoscopic biopsy specimens were obtained during endoscopy of the stomach and duodenum immediately prior to laparotomy or laparoscopic surgery, during which full-thickness biopsy (FTB) specimens were obtained. Accuracy of histopathologic diagnoses was compared between EB and FTB specimens.

RESULTS

Lymphosarcoma was diagnosed in 10 cats on the basis of FTB specimens. Lymphosarcoma was detected in the jejunum and ileum in all 10 cats, in the duodenum in 9 cats, and in the stomach in 4 cats. In the same 10 cats, EB findings indicated a diagnosis of lymphosarcoma in 3 cats and were suggestive but inconclusive for lymphosarcoma in 3 cats. Lymphosarcoma was correctly diagnosed via gastric EB specimens in 3 of the 4 cats with gastric lymphosarcoma but evaluation of EB specimens led to an incorrect diagnosis of IBD in 4 cats with small intestinal lymphosarcoma.

CONCLUSIONS AND CLINICAL RELEVANCE

EB specimens were useful for diagnosis of gastric lymphosarcoma but were not adequate for differentiating between IBD and lymphosarcoma in the small intestine. Because the most common sites of alimentary tract lymphosarcoma in cats are the jejunum and ileum, FTB specimens of those sites should be obtained via laparotomy or laparoscopy for accurate diagnosis. Laparoscopy may be a minimally invasive alternative to endoscopy and laparotomy for obtaining diagnostic biopsy specimens.

Diagnosis and surgical management of vascular ectasia in a dog

CASE DESCRIPTION

An 8-year-old male Golden Retriever was evaluated because of an 8-week history of intermittent diarrhea with melena and hematochezia that were not responsive to medical treatment and resulted in severe anemia.

CLINICAL FINDINGS

Exploratory celiotomy with intestinal and colonic biopsy revealed mild enterocolitis but did not result in diagnosis of the cause of melena and hematochezia. Endoscopy of the upper portion of the gastrointestinal tract and colonoscopy were performed. Multifocal areas of coalescing, tortuous mucosal blood vessels were observed in the cecum and all regions of the colon. A diagnosis of vascular ectasia (VE) was made on the basis of the endoscopic and histologic appearance of the lesions.

TREATMENT AND OUTCOME

An ileorectal anastamosis was performed. Melena and hematochezia resolved within 3 days after surgery, and the anemia resolved within 6 weeks after surgery. Surgical resection of the cecum and colon and feeding of a highly digestible diet resulted in long-term (22 months) resolution of clinical signs.

CLINICAL RELEVANCE

Initial exploratory celiotomy with intestinal and colonic biopsy failed to reveal the VE lesions responsible for the melena, hematochezia, and anemia. Endoscopic evaluation was necessary for detection of the colonic VE lesions. Surgical resection of the cecum and colon and feeding of a highly digestible diet may result in a favorable outcome in affected dogs.

Effects of probiotic bacteria in dogs with food responsive diarrhoea treated with an elimination diet*

We evaluated whether a probiotic supplementation in dogs with food responsive diarrhoea (FRD) has beneficial effects on intestinal cytokine patterns and on microbiota. Twenty-one client-owned dogs with FRD were presented for clinically needed duodeno- and colonoscopy and were enrolled in a prospective placebo (PL)-controlled probiotic trial. Intestinal tissue samples and faeces were collected during endoscopy. Intestinal mRNA abundance of interleukin (IL)-5, -10, -12p40 and -13, tumour necrosis factor-alpha, transforming growth factor-beta1 and interferon (IFN)-gamma were analysed and numbers of Lactobacillus spp., Bifidobacterium spp., Enterococcus spp. and Enterobacteriaceae and supplemented probiotic bacteria were determined in faeces. The Canine Inflammatory Bowel Disease Activity Index, a scoring system comprising general attitude, appetite, faecal consistency, defecation frequency, and vomitus, decreased in all dogs (p < 0.0001). Duodenal IL-10 mRNA levels decreased (p = 0.1) and colonic IFN-gamma mRNA levels increased (p = 0.08) after probiotic treatment. Numbers of Enterobacteriaceae decreased in FRD dogs receiving probiotic cocktail (FRD(PC)) and FRD dogs fed PL (FRD(PL)) during treatment (p < 0.05), numbers of Lactobacillus spp. increased in FRD(PC after) when compared with FRD(PC before) (p < 0.1). One strain of PC was detected in five of eight FRD(PC) dogs after probiotic supplementation. In conclusion, all dogs clinically improved after treatment, but cytokine patterns were not associated with the clinical features irrespective of the dietary supplementation.

Ultrasonographic evaluation of the thickness of the small intestinal wall in dogs with inflammatory bowel disease

OBJECTIVES

To establish whether the intestinal wall thickness, as measured ultrasonographically, is significantly increased in dogs with inflammatory bowel disease (IBD). The results would provide the information necessary to decide whether measurement of ultrasonographic wall thickness can predict IBD in dogs.

METHODS

The intestinal wall thickness of 75 dogs with idiopathic IBD, as measured by ultrasonography, was compared with recently published normal values. IBD was either confirmed histologically (n = 54) or suspected (n = 21). In all cases there was a positive response to immunosuppressive treatment.

RESULTS

A positive association between intestinal wall thickness in dogs and either the histological diagnosis or the response to treatment was not found. Ultrasonographic intestinal wall measurements do not appear to be able to establish a diagnosis of intestinal inflammation and may result in a false negative diagnosis in cases of IBD.

CLINICAL SIGNIFICANCE

The same 'grey zone' of between 4 and 6 mm used in humans can be used in the canine duodenum to distinguish the normal range, reserving the term 'abnormal' for an intestinal measurement greater than 6 mm in the duodenum and greater than 4.7 mm in the jejunum.

Cytokine expression in an ex vivo culture system of duodenal samples from dogs with chronic enteropathies: modulation by probiotic bacteria

There is evidence that probiotics have immune-modulating effects on intestinal inflammation during chronic enteropathies (CE). In an ex vivo culture system we investigated the influence of probiotics on mRNA and protein expression levels of cytokines in intestinal samples from dogs suffering from CE. Duodenal samples of client-owned dogs with CE (group CE; n = 12) were collected during diagnostic endoscopy. Additional duodenal samples of gastrointestinally healthy dogs (group C; n = 4) from an unrelated study were available. Based on histopathological analyses, no pathological changes or only mild to moderate eosinophilic and/or lymphoplasmacytic duodenitis were diagnosed. Tissue samples were cultured: (1) with cell culture medium alone (negative control), (2) with a probiotic cocktail (PC), constituted of three Lactobacilli spp. from healthy canine fecal isolates, (3) with the individual strains of PC, and (4) with a placebo powder. Viability of intestinal tissue and probiotic bacteria before and after culture was evaluated. The mRNA abundance of interleukin (IL)-10, IL-12p40, interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, and transforming growth factor (TGF)-beta1 was analyzed by real-time polymerase chain reaction (RT-PCR). Protein concentrations of IFN-gamma and IL-10 were measured in culture supernatant by ELISA. Results of RT-PCR were expressed as 2(-2DeltaCrossing Point) x 100 after normalization with beta-actin. There was a loss of about 1 log CFU/mL of probiotic bacteria during the incubation period. Viability of tissue was maintained as confirmed by non-significant release of lactate dehydrogenase. In C, addition of PC increased IL-10 mRNA levels (P < 0.1). In CE, PC increased mRNA and protein levels of IL-10 (P < 0.05). On the mRNA level, the ratio of TNFalpha-/IL-10, IFN-gamma/IL-10, and IL-12p40/IL-10 decreased after addition of PC (P < 0.05). The results demonstrate favorable effects of PC on regulatory cytokines relative to inflammatory cytokines that might contribute to reduction of intestinal inflammation.

Chronic inflammatory disorders of the gastrointestinal tract of companion animals

In the inflammatory bowel diseases (IBD) that affect dogs and cats there appears to be dysregulation of normal mucosal immunity, characterised by polyclonal lymphocytic infiltrates which are presumably specific for luminal antigens. There is an absence of a classical polarisation of either T-helper (Th) 1 or Th2 cytokine responses, although increased expression of mRNA for interleukin (IL) 2 and IL-12p40 and a shift towards mucosal immunoglobulin (Ig) G production are consistent findings, whilst variable responses are seen in tumour necrosis factor-alpha (TNF-alpha), IL-1, IL-4, IL-6, and interferon-gamma (IFN-gamma). Increased mucosal permeability and deranged intestinal motility are common sequelae. Despite obvious similarities with Crohn's disease and ulcerative colitis in humans, important differences exist. Of these, the diffuse superficial nature but with no Th1 or Th2 bias, and the prevalence of proximal small intestinal disease are notable. Potential hypotheses for these disparities include specific differences in the types or locations of agonistic gut flora, diffuse abnormalities in microbial-host interactions, a greater importance of diet, or anatomical or cellular differences in mucosal immune responses. Although specific pathogens and genetic susceptibilities may be involved, quantitative or qualitative changes in the normal flora or abnormal responses to a normal flora are more likely to be involved in the immunopathogenesis. Dietary influences include a large source of antigen, promotion of abnormal microbial growth through Maillard compounds within canned diets, and specific macro- and micronutrient deficiencies. Although dependent on a histopathological diagnosis, limitations of biopsies procured endoscopically, lack of histopathological standardisation and difficulty distinguishing inflammation from neoplasia remain significant problems. Clinician-pathologist dialogue, immunohistochemistry, cytokine profiling and lymphocyte clonality assessment may lead to more accurate diagnoses, a deeper understanding of the immunopathogenesis, and ultimately to new therapies or prevention of disease induction.

Complications following full-thickness small intestinal biopsy in 66 dogs: a retrospective study

OBJECTIVES

To retrospectively report the complications seen after full-thickness multiple small intestinal biopsies were performed in 66 dogs.

METHODS

Animals that died as a result of enteric wound breakdown were compared with the surviving population to identify fatal risk factors.

RESULTS

Seventeen dogs had hypoalbuminaemia and eight had albumin levels below 20 g/I at surgery. Twelve dogs had concurrent disease, of which seven had skin disease. Seven dogs suffered minor complications which resolved with treatment. Eight dogs (12 per cent) died or were euthanased between three and nine days postoperatively (mean [sd] 4.5 [2.1]) due to enteric wound breakdown. Seven of these dogs developed septic peritonitis and one died of haemorrhage. No statistically significant differences were identified in any of the parameters examined for the development of fatal enteric wound dehiscence.

CLINICAL SIGNIFICANCE

Full-thickness intestinal biopsy is not a benign procedure. However, this study concludes that there are no consistent predictors for patients at increased risk of enteric wound breakdown.

Clinical Assessment of Disease Activity for Canine Inflammatory Bowel Disease

Clinical indices, consisting of gastrointestinal signs and laboratory parameters, are widely used for assessing disease activity in human inflammatory bowel disease (IBD). The development of a standardized scoring index for use in dogs with IBD would be useful in the management of clinical cases, both at diagnosis and in response to medical therapy. This review provides a synopsis of current strategies used to assess IBD activity in humans and companion animals. The clinical application of a simple scoring index (e.g., canine IBD activity index [CIBDAI]) for measurement of canine IBD activity is also reviewed.

Investigation of Keyes Skin Biopsy Instrument for Intestinal Biopsy Versus a Standard Biopsy Technique

A prospective, clinical trial was conducted using 12 dogs that were presented for intestinal biopsy. Comparisons were made between paired jejunal biopsies collected using a Keyes biopsy punch and a standard scissor excisional technique. There were no differences in speed of collection, diagnostic value of specimens, complication rates, or sample quality. In this study, the Keyes skin punch was found to be safe, rapid, and diagnostic in all animals. Based on results of this study, the use of a Keyes punch instrument can be recommended as an alternative to other open intestinal biopsy methods.

Canine inflammatory bowel disease: retrospective analysis of diagnosis and outcome in 80 cases (1995-2002)

The case records of 80 dogs in which idiopathic inflammatory bowel disease (IBD) had been diagnosed were reviewed, and owners were contacted for follow-up information using a telephone questionnaire. The types of IBD encountered were lymphocytic (n=6), lymphocytic-plasmacytic (n=38), eosinophilic (n=6) and mixed inflammation (n=30). Prednisolone, sulphasalazine, metronidazole and tylosin were the most frequently prescribed medications. At follow-up, 21 dogs (26 per cent) were classified as being in remission (for a median of 14 months), 40 dogs (50 per cent) had intermittent clinical signs (for a median of 17 months) and three dogs (4 per cent) had uncontrolled disease (for a median of 19 months). Ten dogs (13 per cent) had been euthanased due to refractory IBD and four of these had entered remission for a median of 21 months prior to developing severe relapse and refractoriness to further treatment. Six dogs (8 per cent) had been euthanased or had died for reasons unrelated to IBD. Hypoalbuminaemia at the time of diagnosis was significantly associated with a negative outcome (P=0.0007). No association was found between the site (P=0.75), type (P=0.44) and severity (P=0.75) of disease. Dietary change to single protein and carbohydrate commercial diets had no association with outcome (P=0.12). Owner assessment of quality of life at follow-up was significantly associated with outcome (P=0.006).

Diagnostic value of ultrasonography in differentiating enteritis from intestinal neoplasia in dogs

One hundred and fifty dogs with histopathologically confirmed intestinal disease were evaluated retrospectively. Sixty-one dogs had enteritis and 89 dogs had intestinal neoplasia. Ultrasonographic findings including the thickness and distribution of the intestinal lesion, the integrity of intestinal wall layering, regional lymph node thickness, the location of the intestinal segment involved, and regional motility were evaluated. Dogs with intestinal tumor had wall thickness (1.5 cm) significantly greater than dogs with NSE lesions (0.6 cm; p < 0.001). Ninety-nine percent of dogs with intestinal tumor had loss of wall layering while 88% of dogs with NSE had normal or altered wall layering (p < 0.001). Dogs with NSE were significantly more likely to have diffuse lesion (72%) than dogs with intestinal tumor (2%; p < 0.001). Lymph node median thickness in 24/61 dogs with NSE was 1.00 cm. The median thickness of the lymph nodes in 56/89 dogs with intestinal tumors was 1.9 cm. A multivariate analysis showed that loss of wall layering alone was an excellent predictive factor in differentiating intestinal tumor from NSE. In our population, dogs with loss of intestinal wall layering were 50.9 times more likely to have a tumor than enteritis.

Protein-losing enteropathies

GI protein loss can result from a heterogeneous group of diseases, including lymphangiectasia, IBD, neoplasia, ulceration, intussusception, and histoplasmosis. PLE should be suspected in any hypoalbuminemic patient with no evidence of exudative protein loss, proteinuria, or HI. A minimum laboratory database for the suspected PLE patient should include a complete blood cell count, a biochemical and electrolyte profile, urinalysis (+/- urine protein:cretinine ratio), and pre- and postprandial bile acid determinations. Fecal alpha 1-PI concentrations may be used to confirm the presence of GI protein loss in cases with concurrent renal or hepatic disease. Because PLE is a syndrome and not a specific disease, the most effective therapy must be directed at the underlying cause. Multiple high-quality endoscopic biopsies are sufficient to diagnose most patients with PLE, although full-thickness biopsies are required in some cases. Patients with PLE are often clinically "fragile," and careful symptomatic therapy must be integrated with dietary and medical management strategies in most cases.