Making sense of lymphoma diagnostics in small animal patients

Detection of Lymphoid Markers (CD3 and PAX5) for Immunophenotyping in Dogs and Cats: Comparison of Stained Cytology Slides and Matched Cell Blocks

Immunolabeling on Romanowsky-stained cytology (RSC) slides can be used, although there is limited evidence of its suitability for phenotyping canine and feline lymphomas. A comparison with matched cell blocks (CB) is missing. Immunolabeling on RSC and CB was compared for lymphoid markers (CD3 and PAX5) in 53 lymphomas and 4 chylous effusions from dogs and cats. The influence of pre-analytical variables (species, time of archive, type of specimens and coverslipping) and the interobserver agreement among the 2 observers was assessed. Fewer CD3+ lymphocytes were identified in RSC, while the PAX5 positivity by RSC and CB had a substantial agreement. Immunodetection of CD3 and the diagnosis of a T-cell population on RSC was more difficult. Lower intensity and higher background were noted in RSC. Immunophenotyping was inconclusive in 54% RSC and 19% CB. The interobserver reproducibility of immunophenotyping on CB was substantial, being higher than in RSC. The immunolabeling performance on the RSC of effusion and feline samples was unsatisfactory. The detection of lymphoid markers, especially membranous antigens in retrospective RSC, is affected by the pre-analytical variables: species, time of the archive, and type of specimens. CB are a more consistent type of sample for immunophenotyping purposes.

Pathological Findings in Gastrointestinal Neoplasms and Polyps in 860 Cats and a Pilot Study on miRNA Analyses

Background: Gastrointestinal masses in cats are of clinical relevance, but pathological studies with larger case numbers are lacking. Biomarkers such as miRNA have not yet been investigated in feline intestinal neoplasms. Methods: A retrospective analysis of pathology reports included 860 feline gastrointestinal masses. Immunohistochemistry was performed on 91 lymphomas, 10 sarcomas and 7 mast cell tumours (MCT). Analyses of miRNA-20b and miRNA-192 were performed on 11 lymphomas, 5 carcinomas and 5 control tissues by ddPCR. Results: The pathological diagnosis identified 679 lymphomas, 122 carcinomas, 28 sarcomas, 23 polyps, 7 MCT and 1 leiomyoma. Carcinomas and polyps were most commonly found in the large intestine, lymphomas were most commonly found in the stomach and small intestine and MCT only occurred in the small intestine. Besides the well-described small-cell, mitotic count <2 T-cell lymphomas and the large-cell B-cell lymphomas with a high mitotic count, several variants of lymphomas were identified. The values of miRNA-20b were found to be up-regulated in samples of all types of cancer, whereas miRNA-192 was only up-regulated in carcinomas and B-cell lymphomas. Conclusions: The histopathological and immunohistochemical (sub-)classification of feline intestinal masses confirmed the occurrence of different tumour types, with lymphoma being the most frequent neoplasm. Novel biomarkers such as miRNA-20b and miRNA-192 might have diagnostic potential in feline intestinal neoplasms and should be further investigated.

Tumour Incidence in Dogs in Germany: a Retrospective Analysis of 109,616 Histopathological Diagnoses (2014-2019)

Characterization of a tumour entity is based on the precise histopathological diagnosis taking into account the signalment of the diseased animal. The present study is a comprehensive, up-to-date statistical investigation on the type, frequency and breed distribution of neoplasia in dogs in Germany. The histopathological datasets of 109,616 German canine tissue samples (2014-2019) were processed and statistically examined in retrospect. Non-neoplastic diseases were found in 38,650 samples (35.3%) and 70,966 neoplasms (64.7%) were diagnosed. The most common neoplasms were mammary tumours (21.9%), benign epithelial skin tumours (15.4%), mast cell tumour (9.7%), histiocytoma (7.0%), soft tissue sarcoma (5.8%), lipoma (5.8%), melanocytic tumours (5.2%) and odontogenic tumours (4.7%). In general, Beagles, Magyar Vizslas, Boxers, Schnauzers, Spaniels, French Bulldogs and Golden Retrievers had an increased risk of neoplasia (odds ratio 1.17-1.46; all: P ≤0.001) compared with crossbreed dogs. In particular, Boxers, Golden Retrievers, Rottweilers and Schnauzers were often affected by malignant neoplasms, whereas some breeds (eg, West Highland White Terrier, Magyar Vizsla, Chihuahua, Dachshund and Yorkshire Terrier) were frequently affected by numerous benign tumour types. Despite the known risk of haemangiosarcoma in German Shepherd Dogs, other malignant tumours were rare in this breed. Depending on the type of tumour, some purebred dog breeds can have an increased, reduced or identical risk for certain neoplasms compared with crossbreeds. Discussion of breed predispositions to tumour diseases must therefore be conducted critically and with a view to clinical relevance.

Pathohistological features of mediastinal lymphoma in domestic cats

The article covers two clinical cases of domestic cats suffering from a mediastinal form of lymphoma and provides their cytological, immunohistochemical, and pathohistological verification. The lymphoma immunophenotyping method using the B-cell markers CD79a and CD3 was used to identify T-cells. The mediastinal type of lymphoma in cats is usually rarely registered and statistically, the number of cases does not exceed 20%, which is consistent with our observations. Shortness of breath, difficulty with swallowing, lack of appetite, cyanotic mucous membranes, lymphadenomegaly of the mediastinal lymph nodes and effusion in the chest cavity were found in the clinically ill cats. An X-ray examination of the chest cavity revealed an increased contrast in the mediastinal area and displacement of the lungs towards the spine. A complete blood count revealed lymphopenia. Cytological smears of the chest cavity transudates revealed mostly monomorphic lymphoblasts with large rounded hyperchromic nuclei and narrow cytoplasm stained in light blue. The karyoplasm was somewhat granular, the nucleoli were visible, and the mitoses were atypical and numerous. The cytological picture in biopsy samples of mediastinal lymph nodes was characterized by a monomorphic population of lymphoblasts with an eccentrically located nucleus and moderately basophilic karyoplasm. The cell cytoplasm was vacuolated in some places, with presence of atypical mitotic figures. Most of the cells had two nuclei. Diffuse tumoral lesions of the chest cavity tissues, focal tumorous lesions of the lung parenchyma, and lymphadenopathy of the mediastinal lymph nodes were found during the autopsy in the first case. The second clinical case demonstrated the massive lymphadenopathy of the mediastinal lymph nodes. Histologically, a diffuse lesion by a monomorphic population of lymphoblasts was revealed in preparations from the soft tissues of the chest wall. The lymphoblasts’ insignificant cytoplasm, with nuclei from round to elliptical shape, infiltrated the chest wall’s soft tissues. It was found immunohistochemically that the blast cells showed reactivity to CD79a, and were mostly negative to CD3. This indicates the development of a large diffuse B-cell lymphoma. The immunohistochemical picture of lymph node necropsies from another cat was somewhat similar. However, it was also characterized by lymphoblasts with eccentrically placed nuclei, increased number of cells with mitotic figures, somewhat intensive CD3 antibodies expression (especially in the paracortical area of lymph nodes), and significant CD79a marker expression.

Clinical and magnetic resonance imaging features of lymphoma involving the nervous system in cats

Background

Lymphoma is the most common spinal cord neoplasm and second most common intracranial tumor in cats, but description of specific magnetic resonance imaging (MRI) features is lacking.

Objective

Describe the clinical and MRI features of lymphoma affecting the central (CNS) or peripheral (PNS) nervous system or both in cats.

Animals

Thirty‐one cats with confirmed cytological or histopathological diagnosis or both of lymphoma involving the CNS or PNS or both, and MRI findings of the lesions.

Methods

Multicenter retrospective descriptive study. Signalment and medical information were recorded. Magnetic resonance imaging findings were reviewed by 3 observers following a list of predefined criteria and consensus was sought. Frequency distributions of the different categorical data were reported.

Results

Median duration of clinical signs at time of presentation was 14 days (range, 1‐90). Neurological examination was abnormal in 30/31 cats. On MRI, lesions affecting the CNS were diagnosed in 18/31 cats, lesions in both CNS and PNS in 12/31, and lesions in the PNS only in 1/31. Intracranial lesions were diagnosed in 22 cats (extra‐axial, 7/22; intra‐axial, 2/22; mixed, 13/22), and spinal lesions were diagnosed in 12 (6/12 involving the conus medullaris and lumbosacral plexuses). Infiltration of adjacent extra‐neural tissue was present in 11/31 cases. Contrast enhancement was seen in all lesions, being marked in 25/30. Meningeal enhancement was present in all but 2 cases. Several distinct MRI patterns were observed.

Conclusions and Clinical Importance

Nervous system lymphoma in cats has a wide range of MRI features, of which none is pathognomonic. However, together with clinical data and cerebrospinal fluid (CSF) analysis, MRI may provide a strong tentative antemortem diagnosis.

Revisiting lymphocyte clonality testing in feline B-cell lymphoma

Differentiation between resident mature lymphocyte populations and small-cell lymphoma cannot be made by cytological review alone and remains challenging in histopathological review. These cases warrant application of complementary tools like PCR-based immunoglobulin (IG) and T-cell receptor (TCR) clonality testing for confirmation. Although primer coverage of potential IG gene rearrangements in feline B-cell neoplasms constantly improves, the possibility of false negative and false positive test results still poses a problem. In this retrospective study, we assessed diagnostic sensitivity and specificity of a novel developed multiplex PCR assay for routine diagnosis of B-cell clonality. Therefore, 24 feline patients were subjected to comparative clonality testing by using different primer sets. Feline lymphoma cell lines and confirmed patient material served as positive control. Compared to previous studies, this novel developed multiplex PCR assay showed positive effects on diagnostic sensitivity, specificity, accuracy, and positive predictive value accompanied by a slight impairment of negative predictive value. Notably, none of the primer sets was superior; hence, we recommend the combined application of the herein tested primer sets in routine diagnostics. However, a more in-depth-evaluation of the dynamic of assay specific parameters in dependency on primer set usage requires prospective studies on larger cohorts of feline patients.

Flow Cytometric Assessment of Ki-67 Expression in Lymphocytes From Physiologic Lymph Nodes, Lymphoma Cell Populations and Remnant Normal Cell Populations From Lymphomatous Lymph Nodes

Recent literature suggests conventional flow cytometric (FCM) immunophenotyping complemented by Ki-67 FCM assessment as a reliable tool to classify canine lymphomas. Ki-67 expression assessed by FCM is rarely reported in canine lymphoma cases and reference data for normal canine lymph nodes are missing. Moreover, nothing is known about the Ki-67 expression within the occasionally observed remnant cell population within the gates of normal lymphocytes in lymphoma cases. Aim of this study was to compare flow cytometric Ki-67 expression of lymphocyte populations from normal canine lymph nodes, lymphoma cells from World-Health-Organisation (WHO) classified lymphoma patient samples and their neighboring normal remnant cell population. Cryopreserved lymphocyte cell suspensions from normal lymph nodes from eight dogs free of lymphoma served as reference material. Fourteen cases diagnosed by cytology, FCM, clonality testing, histopathology including immunohistochemistry consisting of 10 DLBCL, 1 MZL, 1 PTCL and 2 TZL showed a residual small lymphocyte population and were investigated. The Ki-67 expression in normal canine lymphoid tissue was 3.19 ± 2.17%. Mean Ki-67 expression in the malignant cell populations was 41 ± 24.36%. Ki-67 positivity was 12.34 ± 10.68% in the residual physiologic lymphocyte population, which otherwise exhibited a physiologic immunophenotype pattern. This ratio was equivalent (n = 3) or lower (n = 11) than the Ki-67 expression of the malignant cell population within the sample. This is the first report of FCM derived Ki-67 expression combined with immunophenotype patterns in normal canine lymph nodes, compared with lymphoma cell populations and residual normal cell populations of lymphoma cases diagnosed by state of the art technology.

Ki-67 assessment-agreeability between immunohistochemistry and flow cytometry in canine lymphoma

Recent literature suggests a combination of flow cytometric determination of Ki-67 and immunophenotype as a reliable tool to classify canine lymphomas. Immunohistochemistry (IHC) on histological samples is the gold standard technique assessing Ki-67 index. Agreement between IHC and FCM derived Ki-67 indices has never been investigated. The aim of this study was to investigate the agreement between IHC and FCM in the assessment of Ki-67 expression/index, in order to evaluate whether FCM may serve as a non-invasive alternative method for the estimation of proliferative activity in canine lymphoma. Dogs with previously untreated canine lymphoma undergoing diagnostic lymphadenectomy were prospectively enrolled. Ki-67 expression/index was assessed by FCM and IHC and expressed as percentage of positive cells. 39 dogs classified by histopathology matched the inclusion criteria. With both methods, Ki-67 expression/index was higher in intermediate/high-grade lymphomas. Spearman's coefficient of correlation was ρ = 0.57; (95% CI0.33-0.75) suggesting a moderate correlation. A Bland-Altman plot revealed a negative constant bias of -3.55 (95% CI: -10.52 to 3.42) with limits of agreement from -45.71 to 38.61. The study confirmed agreement albeit with wide confidence intervals between the values of Ki-67 expression/index assessed with FCM and IHC. Discrepancies were observed in a subset of cases. Possible explanation could be that Ki-67 index in IHC is determined in the most proliferative areas of the slide, which could introduce kind of sampling bias, whereas FCM evaluates many more cells in cell suspension. Further studies are warranted to investigate this phenomenon.

Ultrasonographic honeycomb pattern of the spleen in cats: correlation with pathological diagnosis in 33 cases

OBJECTIVES

The aim of this study was to evaluate the relationship between the ultrasonographic (US) diffuse honeycomb pattern (HCP) of the spleen and a pathological diagnosis in cats, and to assess the influence of transducer type on HCP visualisation.

METHODS

Abdominal ultrasounds of cats with an HCP were reviewed and splenic size, shape, margination, other parenchymal alterations and splenic hilar lymphadenopathy were recorded. When applicable, images acquired with high-frequency linear and curvilinear transducers were compared to determine if an HCP was more frequently demonstrated on high-resolution images. A retrospective review of the corresponding splenic cytohistopathological samples was also performed.

RESULTS

Thirty-three cats met the inclusion criteria. Five cases were diagnosed by histology and 28 by cytology, confirmed by PCR for antigen receptor rearrangements (PARR) in uncertain cases. There were 15 cases of lymphoid hyperplasia, eight cases of lymphoma (four B cell, three T cell and one large granular lymphocytes), six cats with splenitis, three with extramedullary haematopoiesis and one with histiocytic sarcoma. The prevalence of lymphoma in cats with an HCP of the spleen was 24%. Splenomegaly was the most frequent US feature associated with an HCP and was observed in all lymphoma cases. In the images obtained from both high-frequency linear and micro-convex transducers the visualisation of an HCP was enabled in all cases (24/24) and in 62.5% (15/24), respectively.

CONCLUSIONS AND RELEVANCE

Based on our findings, a US HCP of the spleen in cats can be associated with benign and malignant disorders and is infrequently associated with lymphoma in comparison with dogs. Cytological or histological examination, possibly supplemented by PARR, should always be performed for diagnostic support. Use of high-frequency linear transducers is recommended to properly recognise an HCP or subtle changes in splenic parenchyma.

Extranodal lymphoma in a bush dog (Speothos venaticus) - case report

ABSTRACT A captive 7-year-old male bush dog (Speothos venaticus) was diagnosed with lymphoma affecting the kidneys, adrenal glands, liver, and spleen. The animal developed renal failure and was euthanized due to poor prognosis. Grossly, both kidneys were enlarged with multiple nodules. Histologically, the neoplasm was an infiltrative and poorly demarcated round cell tumor. Two morphologically distinct cell populations were observed, smaller cells with a lymphocytic morphology, and another population of larger and pleomorphic cells. Most of the smaller cell population, approximately 40% of the population within the neoplasm, were CD3 positive. Neoplastic cells were CD45, CD11d, and granzime B positive, and negative for CD20, CD79a, PAX5, CD163, and myeloperoxidase. This is the first reported case of lymphoma in a bush dog. This report demonstrated the suitability of several cell surface markers for differential diagnosis of round cell tumors in this species.

Clinical and Pathological Data of 17 Non-Epithelial Pancreatic Tumors in Cats

Tumors of mesenchymal origin are rarely reported in the pancreas. Therefore, this study characterized 17 feline non-epithelial pancreatic tumors, including clinical data, histopathology, and immunohistochemistry. Seventeen feline pancreatic tissue samples were investigated histopathologically and immunohistochemically. Selected pancreatic and inflammatory serum parameters, e.g., feline pancreatic lipase immunoreactivity (fPLI), 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester (DGGR) lipase and serum amyloid A (SAA), were recorded, when available. The neoplasms were characterized as round (n = 13) or spindle (n = 4) cell tumors. Round cell tumors included 12 lymphomas and one mast cell tumor in ectopic splenic tissue within the pancreas. Lymphomas were of T-cell (n = 9) or B-cell (n = 3) origin. These cats showed leukocytosis (3/3) and increased fPLI (5/5), DGGR lipase (3/5) and SAA (4/5) values. Spindle cell tumors included two hemangiosarcomas, one pleomorphic sarcoma and one fibrosarcoma. The cat with pleomorphic sarcoma showed increased SAA value. Overall survival time was two weeks to seven months. These are the first descriptions of a pancreatic pleomorphic sarcoma and a mast cell tumor in accessory spleens within feline pancreas. Although rare, pancreatic tumors should be considered in cats presenting with clinical signs and clinical pathology changes of pancreatitis. Only histopathology can certainly distinguish solitary pancreatitis from a neoplasm with inflammation.

Multicenter flow cytometry proficiency testing of canine blood and lymph node samples

BACKGROUND

Flow cytometry (FC) is used increasingly in veterinary medicine for further characterization of hematolymphoid cells. Guidelines for optimizing assay performance and interpretation of results are limited, and concordance of results across laboratories is unknown.

OBJECTIVES

This study aimed to determine inter-investigator agreement on the interpretation of FC results from split samples analyzed in different laboratories using various protocols, cytometers, and software; and on the interpretation of archived FC standard (FCS) data files contributed by the different investigators.

METHODS

This was a multicenter observational cross-sectional study. Anticoagulated blood or lymph node aspirate samples from nine client-owned dogs were aliquoted and shipped to participating laboratories. Samples were analyzed with individual laboratory-developed protocols. In addition, FCS files from a set of separate samples from 11 client-owned dogs were analyzed by participating investigators. A person not associated with the study tabulated the results and interpretations. Agreement of interpretations was assessed with Fleiss' kappa statistic.

RESULTS

Prolonged transit times affected sample quality for some laboratories. Overall agreement among investigators regarding the FC sample interpretation was strong (κ = 0.86 ± 0.19, P < .001), and for specific categories, ranged from moderate to perfect. Agreement of the lymphoproliferation or other leukocyte sample category from the analysis of the FCS files was weak (κ = 0.58 ± 0.05, P < .001).

CONCLUSIONS

Lymphoproliferations were readily identified by FC, but identification of the categories of hematolymphoid neoplasia in fresh samples or archived files was variable. There is a need for a more standardized approach to maximize the enormous potential of FC in veterinary medicine.

Clonality testing in the lymph nodes from dogs with lymphadenomegaly due to Leishmania infantum infection

INTRODUCTION

In southern European countries, multicentric lymphoma and leishmaniosis are the main differential diagnoses in dogs presented with generalized lymphadenomegaly. The cytological examination is in some cases inconclusive and polymerase chain reaction (PCR) for antigen receptor rearrangement (PARR) has become a common method to confirm or rule out a lymphoproliferative neoplasia. According to the literature, leishmaniosis may lead to clonal arrangements and therefore to a false diagnosis of lymphoma, but this assumption is made from a single leishmania infected dog. Therefore, the objective of this study was to prospectively evaluate results from PARR in dogs with lymphadenomegaly due to clinical leishmaniosis at the moment of diagnosis.

MATERIALS AND METHODS

31 dogs with a diagnosis of leishmaniosis based on the LeishVet guidelines were included in the study. Samples from enlarged lymph nodes were taken for cytological examination, clonality testing and Leishmania infantum PCR.

RESULTS

All 31 dogs had medium to high positive antibody titers against Leishmania spp. and 30/31 had a positive Leishmania PCR from the lymph node. A polyclonal arrangement for B cells (immunoglobulin heavy chain gene) and T cells (T-cell receptor gamma chain gene) antigen receptors was found in 28/31 dogs. Two out of 31 dogs showed a monoclonal arrangement for Ig with high (1:2) and low (1:7) polyclonal background respectively; and one of the 31 dogs showed a monoclonal arrangement for T cell receptor with low (1:3) polyclonal background.

CONCLUSION

Infections with Leishmania infantum resulted in clonal rearrangement, and therefore in a possible false diagnosis of lymphoma, in 3 out of 31 dogs (9.7%). Although, PARR is a useful method to differentiate lymphoma from reactive lymphoid hyperplasia in dogs with leishmaniosis, mono-/biclonal results should be interpreted carefully, especially in the presence of any degree of polyclonal background, and together with other clinicopathological findings.

Feline low-grade alimentary lymphoma: an emerging entity and a potential animal model for human disease

BACKGROUND

Low-grade alimentary lymphoma (LGAL) is characterised by the infiltration of neoplastic T-lymphocytes, typically in the small intestine. The incidence of LGAL has increased over the last ten years and it is now the most frequent digestive neoplasia in cats and comprises 60 to 75% of gastrointestinal lymphoma cases. Given that LGAL shares common clinical, paraclinical and ultrasonographic features with inflammatory bowel diseases, establishing a diagnosis is challenging. A review was designed to summarise current knowledge of the pathogenesis, diagnosis, prognosis and treatment of feline LGAL. Electronic searches of PubMed and Science Direct were carried out without date or language restrictions.

RESULTS

A total of 176 peer-reviewed documents were identified and most of which were published in the last twenty years. 130 studies were found from the veterinary literature and 46 from the human medicine literature. Heterogeneity of study designs and outcome measures made meta-analysis inappropriate. The pathophysiology of feline LGAL still needs to be elucidated, not least the putative roles of infectious agents, environmental factors as well as genetic events. The most common therapeutic strategy is combination treatment with prednisolone and chlorambucil, and prolonged remission can often be achieved. Developments in immunohistochemical analysis and clonality testing have improved the confidence of clinicians in obtaining a correct diagnosis between LGAL and IBD. The condition shares similarities with some diseases in humans, especially human indolent T-cell lymphoproliferative disorder of the gastrointestinal tract.

CONCLUSIONS

The pathophysiology of feline LGAL still needs to be elucidated and prospective studies as well as standardisation of therapeutic strategies are needed. A combination of conventional histopathology and immunohistochemistry remains the current gold-standard test, but clinicians should be cautious about reclassifying cats previously diagnosed with IBD to lymphoma on the basis of clonality testing. Importantly, feline LGAL could be considered to be a potential animal model for indolent digestive T-cell lymphoproliferative disorder, a rare condition in human medicine.

Flow cytometry for feline lymphoma: a retrospective study regarding pre-analytical factors possibly affecting the quality of samples

Objectives Flow cytometry (FC) is becoming increasingly popular among veterinary oncologists for the diagnosis of lymphoma or leukaemia. It is accurate, fast and minimally invasive. Several studies of FC have been carried out in canine oncology and applied with great results, whereas there is limited knowledge and use of this technique in feline patients. This is mainly owing to the high prevalence of intra-abdominal lymphomas in this species and the difficulty associated with the diagnostic procedures needed to collect the sample. The purpose of the present study is to investigate whether any pre-analytical factor might affect the quality of suspected feline lymphoma samples for FC analysis. Methods Ninety-seven consecutive samples of suspected feline lymphoma were retrospectively selected from the authors' institution's FC database. The referring veterinarians were contacted and interviewed about several different variables, including signalment, appearance of the lesion, features of the sampling procedure and the experience of veterinarians performing the sampling. Statistical analyses were performed to assess the possible influence of these variables on the cellularity of the samples and the likelihood of it being finally processed for FC. Results Sample cellularity is a major factor in the likelihood of the sample being processed. Moreover, sample cellularity was significantly influenced by the needle size, with 21 G needles providing the highest cellularity. Notably, the sample cellularity and the likelihood of being processed did not vary between peripheral and intra-abdominal lesions. Approximately half of the cats required pharmacological restraint. Side effects were reported in one case only (transient swelling after peripheral lymph node sampling). Conclusions and relevance FC can be safely applied to cases of suspected feline lymphomas, including intra-abdominal lesions. A 21 G needle should be preferred for sampling. This study provides the basis for the increased use of this minimally invasive, fast and cost-effective technique in feline medicine.

Chronic Diarrhea in Dogs - Retrospective Study in 136 Cases

Background

Chronic diarrhea (CD) is common in dogs, and information on frequency and distribution of primary and secondary causes is lacking.

Objectives

To evaluate underlying causes and predictors of outcome in dogs with CD.

Animals

One hundred and thirty‐six client‐owned dogs with CD (≥3 weeks duration).

Methods

Retrospective review of medical records (Small Animal Clinic, Freie Universität Berlin, Germany, 09/2009‐07/2011). Quantification of final diagnoses and comparison of clinical aspects including disease severity and clinicopathological abnormalities among dogs with clinical remission (either complete [gastrointestinal signs absent] or partial [clinical improvement of gastrointestinal signs and reduced episodes with shortened duration]), and those without recovery.

Results

Ninety percent of dogs were diagnosed with a primary enteropathy: inflammatory (71%; of those 66% dietary responsive, 23% idiopathic, 11% antibiotic responsive), infectious (13%), neoplastic (4%), and in one dog each mechanical disease or systemic vasculitis. Secondary causes were diagnosed in 10% of dogs: exocrine pancreatic (6%), endocrine (2%), and in one dog each hepatic, renal, and cardiac disease. In total, 87% of dogs had clinical remission, whereas 13% died or did not respond to treatment: Lack of recovery was frequently recorded for dogs with primary inflammatory (idiopathic) or neoplastic disease and was significantly associated with increased disease severity scores (P = .005), anemia (hematocrit < 40%, P < .001), severe hypoalbuminemia (serum albumin <2.0 g/dL, P = .008), and severe hypocobalaminemia (serum cobalamin concentration <200 pg/mL, P = .006).

Conclusions and clinical importance

Inflammatory enteropathies and particularly those of dietary origin were the most common causes of CD in dogs. Findings support the usefulness of hematocrit, and serum albumin and cobalamin concentration as prognostic markers in dogs with CD.

Association between ultrasonographic appearance of splenic parenchyma and cytology in cats

Objectives The purpose of this study was to determine whether the presence of a splenic mass or a diffusely moth-eaten parenchyma on ultrasonographic scans could represent potential criteria of malignancy in the feline spleen. Methods Feline patients with ultrasonographic images and cytological analysis of the spleen obtained by fine-needle aspiration were retrospectively included in a multicentre study. Results One hundred and ninety-five cats met our inclusion criteria. There was a lack of agreement between the moth-eaten ultrasonographic appearance of the spleen and the presence of a malignant neoplasia on cytological analysis. The sensitivity and specificity of a moth-eaten parenchyma for predicting malignant neoplastic disease were 13.2% and 84.8%, respectively. The sensitivity and specificity of a splenic mass >1 cm for predicting malignant neoplastic disease were 21.0% and 94.7%, respectively. A marbled appearance of the splenic parenchyma was significantly more frequent among patients examined with a high-frequency transducer (11-18 MHz) than among those examined with a low-frequency transducer (6.6-10 MHz) (27.6% vs 11.1%, respectively; P = 0.004). Similarly, although not statistically significant, a moth-eaten parenchyma was more frequent in the high-frequency transducer group than in the low-frequency group (17.1% vs 8.9%, respectively; P = 0.09). Conclusions and relevance Based on our findings, a moth-eaten ultrasonographic appearance of the spleen in cats does not necessarily reflect a lymphoma or another malignant neoplastic process on cytological analysis. The presence of a splenic mass >1 cm on ultrasound is suggestive of malignancy in cats. Finally, the transducer frequency must be taken into account when assessing the splenic parenchyma, as a high-frequency transducer seems to improve the detection of a marbled or moth-eaten parenchyma.

Canine pancytopoenia in a Mediterranean region: a retrospective study of 119 cases (2005 to 2013)

OBJECTIVES

To further clarify the causes of pancytopoenia and to investigate whether underlying cause or severity were associated with survival in an area endemic for vector-borne pathogens.

METHODS

Retrospective review of medical records of 119 dogs with and 238 dogs without pancytopoenia.

RESULTS

Mixed-breed dogs and dogs younger than one year had higher odds of being pancytopoenic. The most common diagnoses included monocytic ehrlichiosis (n=42), leishmaniasis (n=28) and parvoviral enteritis (n=19). The mean white blood cell counts were lower in dogs with ehrlichiosis and parvoviral enteritis compared to dogs with leishmaniasis, while platelet counts were lower in ehrlichiosis compared to leishmaniasis or parvoviral enteritis. Total protein concentrations were lower in dogs with parvoviral enteritis compared to ehrlichiosis and leishmaniasis. Higher haematocrit, platelet and white cell counts were associated with better odds of survival.

CLINICAL SIGNIFICANCE

Infectious diseases appear to be the leading causes of canine pancytopoenia in endemic areas; severe leukopoenia (ehrlichiosis, parvoviral enteritis), thrombocytopoenia (ehrlichiosis) and hypoproteinaemia (parvoviral enteritis), represented potentially useful disease-specific diagnostic determinants. The severity of pancytopoenia significantly affects the clinical outcome.

Novel use of immunohistochemistry for phenotypic evaluation of circulating neoplastic lymphocyte populations

CASE HISTORY

A 5-year-old male neutered Poodle cross presented with a 2-week history of non-specific gastrointestinal signs including vomiting, inappetence and lethargy (Case 1). A 14-year-old male neutered Staffordshire Bull Terrier presented with a 6-week history of progressive inappetence and lethargy (Case 2).

CLINICAL FINDINGS

On presentation, Case 1 was dehydrated and had repeatable cranial abdominal pain. Mild hypoproteinemia with hypoalbuminemia, and electrolyte disturbances were found on biochemistry profile. Abdominal ultrasonography showed moderate diffuse small intestinal wall irregularity and moderate local lymphadenopathy. Haematology was repeated 2 days after initial presentation and showed a marked leucocytosis associated with an elevated circulating neoplastic cell population. On presentation, Case 2 was dehydrated, had palpable hepatomegaly and a mild generalised lymphadenopathy. A low number of large, atypical lymphocytes were found on haematology. Sonographically there was hepatomegaly with diffuse parenchymal changes and severe mesenteric lymphadenopathy.

LABORATORY FINDINGS

Aspirates from the abdominal lymph nodes (Cases 1 and 2) and liver (Case 2), and blood smears revealed atypical neoplastic lymphoid populations, predominantly comprising large lymphocytes. Immunocytochemistry failed to determine the lymphoid phenotype in Case 1 but supported a T cell phenotype in Case 2. Immunohistochemistry of formalin-fixed paraffin-embedded (FF-PE) blood clots was able to identify a T cell phenotype in both cases. PCR for antigen receptor rearrangement results from both cases were consistent with an expanded T cell population.

DIAGNOSIS

In both cases, immunohistochemistry on FF-PE blood clots revealed a circulating T cell lymphocyte population, consistent with T cell lymphoproliferative neoplasia.

CLINICAL RELEVANCE

Immunohistochemistry on FF-PE blood clots offers clinicians a reliable, inexpensive and minimally invasive method of phenotyping neoplastic cells in circulation. Compared to other available methods, prolonged sample stability allowing for transport and retrospective examination is a distinct advantage. This technique should be considered a useful adjunct to the currently available methods for the phenotypic evaluation of lymphoid leukaemia in dogs.

Cytology of endoscopically obtained biopsies for the diagnosis of chronic intestinal diseases in cats

OBJECTIVE

To evaluate the diagnostic value of cytology of endoscopically obtained biopsies in cats presented for chronic gastrointestinal complaints with emphasis on the diagnosis of low-grade alimentary lymphoma (LGAL).

MATERIALS AND METHODS

Data of endoscopically obtained duodenal biopsies from 137 cats were evaluated retrospectively. Cytology was performed using the squash smear technique with subsequent Diff Quick® staining. Pathological findings were categorized according to type and grade of the inflammatory infiltrate. Moreover, reports were reviewed with regard to diagnosis of LGAL. Histopathology reports were analysed correspondingly and compared to cytology results. Histopathological samples were further evaluated by immunohistochemistry (IHC) if a diagnosis of LGAL had been expressed.

RESULTS

Squash smear preparation of intestinal biopsies was adequate for cytological examination in >97% of cases. Using histopathology as gold standard, with cytology, a sensitivity and specificity for detection of a pathologic process in feline intestinal biopsies of 68.1% and 70.6% were calculated, respectively. Regarding the detection of lymphoplasmacytic (LPE) and eosinophilic enteritis a statistically significant correlation with histopathology (p<0.05) was observed. With regard to grade of the inflammatory infiltrate, a weak correlation was calculated (r=0.482). Of 21 cats diagnosed or suspected with LGAL by cytology, IHC confirmed nine cases whereas 11 cases were reclassified as LPE. None of the confirmed LGAL had been missed with histopathology. A sensitivity of 60.0% and specificity of 90.6% for cytological detection of feline LGAL was obtained.

CONCLUSION AND CLINICAL RELEVANCE

The sensitivity of cytology to diagnose LGAL is low and it has no additional significance to histological biopsies.

Application of flow cytometry in diagnosing lymphomas in dogs and cats

Classification of types of lymphomas is done by interpreting cell morphology results obtained in cytological and/or histological examinations. In recent years, additional methods like immunocytochemistry (ICC), immunohistochemistry (IHC), immunophenotyping by flow cytometry and polymerase chain reaction (PCR) for antigen receptor rearrangements (PARR), have been used to diagnose and classify lymphomas. Unfortunately, none of these methods is completely specific and sensitive. Thus, a combination of several diagnostic methods or use of all available techniques allows for evaluation of morphological properties of cells like their maturity and diversification. Owing to the use of sets of antibodies it is possible to identify the phenotype of hyperplastic cells as well as their origin. Combination of results obtained through phenotypical analysis with flow cytometry examination with morphological, histological and genetic testing enables a detailed analysis of, in this case, lymphoproliferative diseases including reaction changes, primary and secondary immunological deficits as well as autoimmune diseases.