Walter Bertazzolo

Sensitivity of Tru‐cut and fine‐needle aspiration biopsies of liver and kidney for diagnosis of feline infectious peritonitis

Background: The detection of typical lesions and feline coronavirus (FCoV) antigen in tissues is the only conclusive method for making a diagnosis of feline infectious peritonitis (FIP). A positive result using Tru‐cut biopsy (TCB) and fine‐needle aspiration biopsy (FNAB) has high diagnostic specificity, but information about the capacity of these techniques to correctly identify cats with FIP lesions is not available. Objectives: The diagnostic sensitivity of TCB and FNAB for detecting liver and kidney histologic lesions caused by FIP was evaluated. Methods: TCB and FNAB specimens collected mainly at necropsy from 25 cats with FIP were analyzed. Diagnostic sensitivity was calculated on the basis of the number of false‐negative and true‐positive specimens, compared with the number of organs bearing histologic lesions of FIP. Results: Diagnostic sensitivity was higher for hepatic TCB (64%) and FNAB (82%) than for renal (39% and 42%, respectively) procedures. A high percentage of renal cytologic and TCB specimens were inadequate. Combined analysis of TCB and FNAB specimens collected from the same organ increased the diagnostic sensitivity for liver (86%) and kidney (48%). The sensitivity of immunohistochemical/cytochemical analysis was low (11–38% depending on the technique), probably due to variable distribution of feline coronavirus in the lesions. Conclusion: Biopsy of liver and kidney can correctly identify FIP lesions. However, false‐negative results or inadequate samples occur with moderate frequency, especially for immunochemical analysis. Diagnostic sensitivity may be increased when both TCB and FNAB specimens from the same organ are examined.

Clinicopathological Findings in Five Cats with Paw Calcification

This retrospective study describes the clinicopathological findings in five cats with soft tissue mineralisation of interdigital spaces and footpads. Paw disease was the reason for veterinary consultation in three out of five cats. All cats had laboratory findings suggestive of renal failure and high solubility product [calcium x phosphorus]. In all cases, cytological examination of paw lesions was suggestive of calcinosis. The results of our study agree with two previous case reports of paw calcification in the cat, suggesting a metastatic pathogenesis and a correlation between paw mineralisation and renal failure.

Accuracy of cytology in distinguishing adrenocortical tumors from pheochromocytoma in companion animals.

BACKGROUND The distinction between adrenocortical tumors and pheochromocytoma can be challenging using clinical findings, diagnostic imaging and laboratory tests. Cytology might be a simple, minimally invasive method to reach a correct diagnosis. OBJECTIVES The purpose of this study was to assess the accuracy of cytology in differentiating cortical from medullary tumors of the adrenal glands in dogs and cats. METHODS Cytologic key features of adrenocortical tumors and pheochromocytoma were defined by one reference author. Cytologic specimens from primary adrenal tumors were submitted to 4 cytopathologists who were asked to classify the tumors based on the previously defined key features without knowledge of previous classification. RESULTS Twenty specimens from histologically confirmed adrenal tumors (Group 1) and 4 specimens from adrenal tumors causing adrenal-dependent Cushings syndrome (Group 2) were evaluated by the 4 cytopathologists. Accuracy in differentiating cortical from medullary origin ranged from 90% to 100%, with a Kappa coefficient of agreement between cytopathologists of 0.95. CONCLUSIONS The origin of an adrenal tumor can be easily determined by cytology alone in many cases. However, cytology was not reliable in distinguishing benign from malignant neoplasia. Additional studies are needed to assess possible risks and complications associated with fine-needle biopsy of adrenal tumors in dogs and cats.

Detection of biclonal gammopathy by capillary zone electrophoresis in a cat and a dog with plasma cell neoplasia

Gammopathies associated with plasma cell neoplasms in a 15-year-old female spayed domestic shorthaired cat and a 9-year-old female spayed Rottweiler dog were evaluated by serum protein electrophoresis. In the cat, the plasma cell neoplasm was found in the liver and spleen, and an evaluable sample of bone marrow was not obtained. Some of the plasma cells had the morphologic appearance of flame cells. The paraprotein was confirmed as IgG based on agar gel immunodiffusion precipitation and both immunocytochemical and immunohistochemical staining. The dog had multiple myeloma with production of IgG and IgA paraproteins. In both cases, serum proteins were evaluated by 2 methods of protein electrophoresis: cellulose acetate electrophoresis (CAE) and capillary zone electrophoresis (CZE). In the cat and the dog, CAE showed a single large oligoclonal-like peak, which occurred in the γ-region in the cat and the β-γ-region in the dog, whereas CZE showed a biclonal gammopathy with 2 very close narrow spikes in the γ- and β-γ-regions in the cat and dog, respectively. In selected cases, CZE may be more effective than routine CAE in distinguishing oligoclonal from monoclonal or biclonal paraproteinemia.

Evaluation of C-reactive protein as a clinical biomarker in naturally heartworm-infected dogs: a field study.

Canine heartworm disease caused by Dirofilaria immitis is considered a pulmonary disease, which leads to pulmonary hypertension, and in the late stage, may induce right cardiac insufficiency. Adult worms are localized in the pulmonary arteries, which undergo endothelial damage (proliferative endoarteritis), the severity of which depends on the duration of infection and the worm burden. C-reactive protein (CRP) is a major canine acute-phase protein that rapidly increases in a wide range of inflammatory conditions and rapidly decreases when inflammation resolves. CRP is therefore considered a sensitive but nonspecific marker of inflammation. Pulmonary arterial damage in canine heartworm may induce an increase in CRP concentrations similar to what occurs in humans with endoarteritis. The aim of the present study was to investigate whether CRP may be a diagnostic and/or prognostic marker in canine heartworm, whether it may be used for staging and monitoring canine heartworm, and whether its concentration depends on worm burden or on pulmonary arterial damage. Serum CRP concentrations were determined in 57 dogs with heartworm disease, 47 of which were grouped according to parasite burden (low: n=11; high: n=10) or on severity of pulmonary hypertension (mild: n=16; severe: n=10). An additional 23 heartworm-free cardiopathic dogs were grouped on the absence of pulmonary hypertension (n=8), presence of dilated cardiomyopathy (DCM) (n=6), or presence of cardiomyopathy and pulmonary hypertension (n=3) due to previous heartworm disease that had been treated (n=6). Twenty control dogs also were sampled for CRP concentrations. Results show that CRP was significantly increased (p<0.001) in dogs with heartworm or cardiomyopathy compared with concentrations in controls. In the heartworm group, CRP was significantly increased (p<0.001) in dogs with mild or severe pulmonary hypertension but not in dogs with low or high parasite burden without pulmonary hypertension. Heartworm-free cardiopathic dogs had significantly high (p<0.01) CRP concentrations if affected by DCM or pulmonary hypertension. ROC curves showed that CRP has good discriminating power for pulmonary hypertension (AUC=0.92 for the entire dataset, 1.00 for dogs with heartworm) and that pulmonary hypertension in heartworm must be suspected when CRP values are higher than 6.8 mg/dL. Conversely, severe pulmonary hypertension is suspected only if CRP values are very high (>29.8 mg/L). In conclusion, CRP can be used as a marker of endothelial arteritis and pulmonary hypertension in dogs with heartworm.

Cellulose acetate electrophoresis of canine plasma after fibrinogen precipitation by ethanol

BACKGROUND In routine canine medicine, anticoagulated blood is often the only sample sent to laboratories for diagnostic purposes. This hampers the interpretation of protein electrophoretic tracings because plasma contains fibrinogen, which migrates in the beta-gamma region. In human medicine, fibrinogen can be precipitated from plasma using ethanol. OBJECTIVES The purpose of this study was to assess ethanol precipitation as a method for removing fibrinogen from canine plasma so as to facilitate the interpretation of electorphoresis results. METHODS Blood samples collected from 40 dogs were divided into plain tubes and tubes containing EDTA (n=20) or lithium-heparin (n=20). An aliquot of plasma from each sample was incubated with ethanol at a final concentration of 100 mL/L. Cellulose acetate electrophoresis was then performed on serum, plasma, and plasma treated with ethanol. To verify the efficiency of ethanol treatment, fibrinogen was added to 5 canine serum samples at final concentrations of 2.5, 5.0, and 10.0 g/L, and electrophoresis was performed before and after ethanol treatment. RESULTS Visual analysis of electrophoretograms from ethanol-treated samples confirmed the disappearance of the fibrinogen peak from the beta(2)-globulin region. Treatment with ethanol caused a significant decrease in the percentage of beta(2)-globulins and a significant increase in the percentage of alpha(2)-globulins. Absolute values of most electrophoretic fractions were significantly decreased in ethanol-treated plasma compared with serum. CONCLUSIONS Ethanol treatment successfully removed fibrinogen from canine plasma and normalized electrophoretic profiles, but probably also precipitated proteins other than fibrinogen. Ethanol treatment is recommended to facilitate visual identification of abnormal monoclonal peaks, but not for determining absolute protein concentrations in electrophoretic fractions.

The effect of inter-laboratory variability on the protein:creatinine (UPC) ratio in canine urine

Quantification of proteinuria is a fundamental step in staging dogs with chronic kidney disease and in monitoring the course of disease or the efficacy of anti-proteinuric treatments. Analytical precision and accuracy of the proteinuria assessment could be affected by several factors such as biological variability, different operators and quality control materials. The aim of this study was to assess whether inter-laboratory variability could affect the urinary protein to creatinine (UPC) ratio and whether this variability may affect patient classification according to the International Renal Interest Society (IRIS) sub-staging system. The same urine samples were analysed in three different laboratories using different instruments and different reagent brands. The results of the three laboratories were highly correlated to each other although urinary protein (UP), urinary creatinine (UC) and the UPC ratio of one laboratory were found to be significantly higher than those of the other two. No significant differences between the other two laboratories were recorded. The concordance in classifying dogs according to the IRIS guidelines was good if all three proteinuria categories were analysed separately or if borderline proteinuric (BP) dogs were included in the proteinuric group, and very good if BP dogs were merged into the non-proteinuric group. The inter-laboratory variability in UPC ratio measurement was not so great as to impede the identification of proteinuric dogs, but may influence the estimation of the magnitude of proteinuria.

Cytologic features and diagnostic accuracy of analysis of effusions for detection of ovarian carcinoma in dogs

BACKGROUND Presence of an abdominal effusion is a typical presenting sign associated with ovarian carcinoma (OC) in dogs. OBJECTIVES The aims of this study were to describe the cytologic features of effusions associated with OC and to evaluate the diagnostic accuracy of such features for the diagnosis of OC in dogs. METHODS Cytologic evaluations of 7 OC-associated peritoneal effusions in dogs were used to define cytomorphologic features of this neoplasm. Then, in a blinded study to evaluate the accuracy of these features in identifying OC, 2 independent board-certified clinical pathologists reviewed 82 pleural, pericardial, and abdominal effusions resulting from OC (n = 7), other neoplasms (n = 40), and non-neoplastic disorders (n = 35). The clinical pathologists were instructed to identify all samples containing papillary structures typically seen in OC and then apply the cytomorphologic criteria determined in the first part of the study to diagnose OC. RESULTS Effusions associated with OC contained blood and had moderate to high cellularity, with neoplastic cells arranged in a prominent papillary pattern in which intercellular spaces were not clearly evident. Individual cells were approximately 30 μm in diameter, with mild anisocytosis and anisokaryosis, moderate amounts of pale blue cytoplasm, and round to oval paracentral nuclei with fine chromatin and poorly distinct small nucleoli. Using these cytologic features to identify OC in the 82 effusions, sensitivity was 86% and 100% and specificity was 57% and 97% for the 2 clinical pathologists. Overall accuracies in distinguishing OC from other effusions were 98.8% and 93.9%. CONCLUSION Based on this preliminary study, effusion cytology from intact female dogs affected by OC appears to be useful in suggesting a diagnosis of neoplasia. The presence of cells with a prominent and uniform papillary pattern in peritoneal and pleural effusions in dogs with appropriate signalment and clinical signs should prompt a search for primary ovarian neoplasia.

Cytological and histological correlation in diagnosing feline and canine mediastinal masses

OBJECTIVES The aim of this study was to evaluate the agreement between cytological and histological diagnosis of canine and feline mediastinal masses to assess the utility of cytological examination in accurately diagnosing and classifying mediastinal lesions. METHODS A retrospective review of 58 cases of mediastinal masses from 21 dogs and 37 cats were performed. Histopathology was used as the diagnostic reference standard. The agreement between cytological and histological diagnosis was calculated. RESULTS The complete agreement between cytological and histological classification ranged from substantial (k = 0 · 72, CI: 0 · 64 to 0 · 80) to almost perfect (k = 0 · 89, CI: 0 · 82 to 0 · 96) depending on how the cytological diagnoses classified as suspicious were used for statistical calculations. CLINICAL SIGNIFICANCE Cytological examination of canine and feline mediastinal masses is a relatively easy, low-cost procedure, with good agreement with final histological diagnoses.

Pericardial lymphoma in seven cats.

A presumed primary pericardial lymphoma was diagnosed in seven cats. Clinical findings at presentation included poor body condition, dehydration and dyspnoea. Thoracic diagnostic imaging was performed in six cases and revealed pleural effusion and a diffuse thickening of the pericardium. A cytological diagnosis of lymphoma was obtained in six cases; in four cases the diagnosis was confirmed at necropsy. Immunophenotyping was performed in six cases: three cases were classified as T-cell and three as B-cell lymphoma. Four cats did not receive any treatment. One cat received only prednisone and two cats received chemotherapy. Six cats lived 7–11 days, except for one cat that received a multi-drug chemotherapy protocol and was still alive at the time of writing (750 days after diagnosis). Primary pericardial lymphoma is a rare extranodal feline lymphoma that has never been described previously.