The perceived and actual diagnostic utility of veterinary cytological samples

O bjectives : To establish the proportion of cytology samples sent to a commercial veterinary laboratory that yields diagnostically useful information in the context of current use and perceptions of cytology.
M ethods : Nine hundred and forty-five cytology submissions were retrospectively collected and categorised according to diagnostic utility. A survey into the use and perceptions of cytology was distributed at the British Small Animal Veterinary Association Congress 2008.
R esults : A specific diagnosis was reached in 23·1 per cent of samples and a cytological diagnosis in 35·3 per cent. 22·4 per cent of samples yielded some useful information, but 19·2 per cent were unacceptable. Seventy-four participants in the survey took an average of 3·9 cytological samples per week, of which they examined 27·0 per cent in-house only, 21·6 per cent in-house before sending to an external laboratory and 51·4 per cent were sent externally without prior examination. "To obtain a definitive diagnosis" was the principal reason cited for performing cytology.
C linical S ignificance : Results suggest that cytology is underused and may be applied in an inappropriate context in the UK. It is hoped that illustrating the diagnostic outcome of samples received by a commercial laboratory will encourage increased, appropriate use of cytology.     

Lymph node cytology

In clinical practice, animals with lymphadenopathy are eminently suitable candidates for cytology sample collection by FNAB from several enlarged nodes; or, if surgical biopsies are made, imprint smears from the tissue may yield diagnostically useful information to supplement the histological findings. Cytology may reveal the lesion to be reactive, inflammatory, or neoplastic. Cytologically, reactive nodes will contain increased numbers of plasma cells, possibly with some inflammatory cells, along with the resident lymphoid population. If inflammation is present, neutrophils and macrophages also will be found and the type of inflammation may be classified. Any infectious agent such as fungal hyphae, yeasts, bacteria, and protozoa also may be demonstrated. Aspirates may be cultured directly onto blood agar plates or transported in nutrient broth for culture at a referral laboratory. In chronic dermatopathic nodes, a mixed inflammatory cell infiltrate is expected, and in pruritic skin disorders, eosinophils usually are plentiful in node aspirates. Increased numbers of eosinophils also may be found in dogs that are microfilaremic with heartworm infection. Background debris of hemosiderin and melanin pigment and other fine particles may occur in some chronic inflammatory lymphadenopathies. Metastatic lesions are identified by the presence of foreign neoplastic cells, but this diagnosis may be missed in early metastatic spread or if the aspirate is not sufficiently cellular. A cytological guide to the classification of the more common diffuse canine lymphomas is provided but full characterization of the lymphoma type may require histology and immunocytochemistry. In practice, a simple differential Romanowsky stain such as Diff Quik is suitable for most purposes. Supplementary stains using 1 per cent toluidine blue may increase the detection of mast cells. Aspirates also may be transferred into suitable media for transport to a referral diagnostic laboratory for cytocentrifugation or further tests such as electron microscopy, immunocytochemistry, flow cytometry, and culture. Although definitive diagnosis by histopathology and other tests still may be required, in many routine cases, diagnoses can be achieved expediently in clinical practice by aspiration cytology.     

Tumors of pet birds.

Neoplastic diseases are becoming more than a postmortem diagnosis due to the increasing knowledge base and improving quality of avian medicine. The expectation for better health care demands a diagnosis, prognosis, and therapy options. However, the published information regarding prognosis and therapy of specific neoplasms remains limited in avian medicine. With each case report or study that provides this information, there is an improvement in the level of care we can offer our companion avian species. This review will cover some basic information about specific tumor types and will reference the more recent reports in the avian literature. It is not intended to be all encompassing.     

Cytology of the respiratory tract

Information has been presented to assist veterinary practitioners in obtaining and interpreting cytology specimens from the respiratory tract. The various cytologic techniques are rapid, economical, and relatively noninvasive. Cytologic examination of the respiratory tract may provide a definitive diagnosis or information for improved case management until more complex diagnostic procedures are performed.     

Practical aspects of immunocytochemistry in canine lymphomas

The aim of this study was to evaluate the utility of immunocytochemistry in a standard veterinary practice and to determine the immunophenotype of tumor cells in cases of multicentric lymphoma in dogs by immunocytochemical analysis of fine-needle biopsy specimens. The study was performed on cytological samples collected from 54 dogs, in which multicentric lymphoma was recognised based on clinical data, cytology or cytology and histology, and follow-up information. Diagnosis of lymphoma was established according to the updated Kiel classification. Immunocytochemical assays were conducted using commercially available antibodies to the pan T-lymphocyte marker CD3 and B cell antigen receptor complex CD79 alpha. Among all animals examined B cell lymphoma was recognized in 42/54 (77.8%) of cases, while in the remaining 12/54 (22.2%) of dogs T cell lymphoma was recognized. In 11 animals with lymphoma recognized cytologically, in which an entire lymph node was obtained for histology, the results of routine cytology and immunocytochemistry fully corresponded with findings revealed by histology and immunohistochemistry. Immunocytochemistry can be successfully conducted in smears stored at room temperature for 24 hours without changes of staining results. It can be stated that application of standard cytopathological assessment in connection with immunocytochemistry of lymph nodes samples collected from dogs with lymphoma is a method of choice for establishing final diagnosis, and avoids the need for reexamination or collection of tissue samples for histopathology and immunohistochemistry during surgical procedures in ambiguous cases.     

Diagnostic cytology in avian medicine

Diagnostic cytology in avian medicine provides a means for better disease definition in the avian patient, which allows for a more specific therapeutic regimen. It is important that cytologic specimens are from fresh sources, since cells degenerate rapidly following the death of the bird or the tissue. Cytologic evaluation is an adjunct to other diagnostic procedures. A definitive diagnosis often requires information from the clinical history, physical examination, evaluation of samples obtained from the bird, radiographs, surgical procedures, necropsy, and histopathology.     

A novel method of core aspirate cytology compared to fine-needle aspiration for diagnosing canine osteosarcoma

There is little information in veterinary literature regarding the diagnostic accuracy of aspirate cytology for the diagnosis of canine osteosarcoma (OSA). The authors compared the diagnostic accuracy of a novel method of cytologic collection, termed core aspirate cytology (CA), with fine needle aspiration (FNA) and histopathology in 27 dogs with lytic and/or proliferative bone lesions. Alkaline phosphatase (ALP) staining was performed to confirm the diagnosis of OSA cytologically. OSA was accurately diagnosed in 85% and 95% of FNA and CA, respectively. ALP staining was 100% sensitive for the diagnosis of OSA. CA using a bone marrow biopsy needle allowed for penetration of cortical bone and aspirate cytology with a larger bore needle than FNA; however, there was no significant difference in diagnostic accuracy between techniques. Aspirate cytology with ALP staining was a safe, accurate, and minimally invasive diagnostic test for the evaluation of suspected OSA lesions in dogs.     

Use of cytology as a diagnostic method in veterinary practice and assessment of communication between veterinary practitioners and veterinary clinical pathologists

OBJECTIVE: To determine the extent of use of cytology as a diagnostic method in veterinary practice and assess how veterinarians in practice communicate with veterinary clinical pathologists. DESIGN: Online survey. STUDY POPULATION: 870 veterinarians. PROCEDURES: An online survey was made available to members of the Veterinary Information Network from October 1, 2004, through December 1, 2004. RESULTS: Respondents reported obtaining a median of 7 cytology samples weekly (range, 0 to 100). On average, respondents reported that 48.1% of the samples they collected were evaluated in-house, 29.5% were submitted to a veterinary diagnostic laboratory, and 21.6% were evaluated in-house and then submitted to a diagnostic laboratory. Most respondents (89.2%) reported using cytologic assessments to guide additional testing, and most (80.3%) indicated that they found the comments section of the cytology report to be the most important section. When asked to indicate the importance of various factors in their decision to use cytology as a diagnostic method, respondents overwhelmingly indicated that accuracy was very important. The most common reasons for consulting with a clinical pathologist were to discuss a discrepancy between clinical and cytologic findings, to clarify a diagnosis, and to ascertain the pathologist's confidence in a diagnosis. Respondents expressed more confidence in results when board-certified clinical pathologists were examining cytology samples than when others were. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that improving communication between veterinary practitioners and veterinary clinical pathologists could enhance the diagnostic value of cytologic examinations and improve clinical decision-making.     

Laboratory tests for diagnosing and monitoring canine leishmaniasis

Although several reviews on canine leishmaniasis have been published, none thoroughly described clinicopathologic abnormalities and their clinical usefulness. The aim of this review was to provide information concerning current diagnostic tests relevant for clinical pathologists and from a practical perspective. Specifically, in canine leishmaniasis, nonregenerative normocytic normochromic anemia, thrombocytopenia, or leukogram changes may be present. Clinical chemistry and urinalysis may indicate renal dysfunction (azotemia, decreased urine specific gravity, proteinuria) and an inflammatory/immune response (increased acute phase proteins [APP] or α₂‐ and/or γ‐globulins). Although a potential gammopathy is usually polyclonal, it may also appear oligo‐ or monoclonal, especially in dogs coinfected by other vector‐borne pathogens. When lesions are accessible to fine‐needle aspiration (lymphoadenomegaly, nodular lesions, joint swelling), cytology is strongly advised, as the presence of Leishmania amastigotes in a pattern of pyogranulomatous inflammation or lymphoplasmacytic hyperplasia is diagnostic. If the cytologic pattern is inconclusive, the parasite should be identified by histology/immunohistochemistry or PCR on surgical biopsies. Alternatively, cytology and PCR may be performed on bone marrow samples where amastigotes, along with erythroid hypoplasia, myeloid hyperplasia, plasmacytosis, or secondary dysmyelopoiesis can be observed. Dogs with overt leishmaniasis generally have high antibody titers, while low titers predominate in immunologically resistant infected dogs or in exposed dogs with no parasite confirmation. Quantitative serology is recommended in clinically suspect dogs as high‐titer antibodies titers may confirm the clinical diagnosis. In confirmed and treated dogs, renal function and inflammatory/immune response variables should be periodically monitored.     

Equine endometrial cytology

The simplicity of collection of material for cytologic preparations belies the complexity of smear interpretation beyond recognition of neutrophils. Knowledge concerning cancer cytology moves rapidly, for cancer is a progressive, often fatal disease so that tissue for comparison and confirmation of interpretation often becomes available. This is not true for cytologic study of the equine endometrium. Lesions detected by means of cytology smears may be transient and regress, offering little information concerning their etiology or consequences. They may be focal and missed in the corresponding biopsy. Such experiences should lead to the abandonment of equine endometrial cytology, but have only strengthened our interest and enthusiasm for this technique in the study of the uterus. We have found it to be useful in a limited number of clinical circumstances in which other techniques have failed. This, plus the growing number of supportive clinicians using cytopathology service and the large number of mares with fertility problems, leads us to believe that further investigation of equine endometrial cytology may prove to be even more helpful as a clinical tool.     

Nasopharyngeal disease in cats: 1. Diagnostic investigation

PRACTICAL RELEVANCE: Nasal discharge, sneezing and upper respiratory noise are frequent presenting signs in feline practice. CLINICAL CHALLENGES: The small nasal cavity of the cat can make visualisation of lesions challenging. In addition, investigations may identify only secondary complications of a disease process, rather than the initial aetiological agent. GLOBAL IMPORTANCE: Nasopharyngeal disease is a worldwide problem. However, fungal disease shows regional variations in prevalence. AUDIENCE: This review, aimed at general practitioners as well as those undertaking more specialist investigations in feline respiratory disease, aims to provide practical guidance on the approach necessary to obtain a diagnosis in cats with nasopharyngeal disease. It should also help to explain why a specific diagnosis may not always be possible. EQUIPMENT: While access to endoscopy and computed tomography is advantageous, extensive information can be gained from equipment readily available in all practices. EVIDENCE BASE: The information presented in this article is based on peer-reviewed publications and the clinical experience of the authors.     

Diagnosis of feline viral infection

A diagnosis of a specific viral disease in the cat involves a combination of an accurate history, careful observation of disease signs, demonstration of characteristic clinical pathologic changes, and isolation or identification of the virus. Isolation or identification of a virus from the patient does not establish that the disease observed was caused by the virus so isolated or identified; correlation and proper interpretation of all findings are necessary to establish a diagnosis. Virus identification may involve office laboratory tests, such as cytology or ELISA, or more specialized procedures. Whether specimens are to be sent out for specialized tests or office laboratory procedures are to be used, the veterinary practitioner must not only know what specimens are required but must also understand the test and be able to properly interpret the results in light of the patient's observed condition.     

Coccidioidomycosis: a diagnostic challenge

Coccidioidomycosis is a systemic fungal infection acquired endemically in the southwestern United States. Clinical disease is quite common in the dog; though less frequently recognized in the cat, disease is often severe at the time of diagnosis. Diagnosis can be a challenge because serology, while specific, is not very sensitive and quantitative titration of antibodies does not correlate entirely with clinical disease in dogs. Radiographs, serum biochemistry tests and complete blood counts are beneficial additions to the database when establishing a diagnosis; cytology, histopathology, and culture are definitive when available. Advanced imaging can detect central nervous system and subtle skeletal lesions. Disease can occur in most organs of the body and may prove a diagnostic challenge requiring several modalities. Coccidioidomycosis may need to be considered both in animals in the endemic region and in those with a travel history through it.     

Diagnostic methods in animal trypanosomiasis

The methods of diagnosis of pathogenic African trypanosomiasis of livestock are reviewed in this paper. Clinical diagnosis, although it may be important in some situations, is not considered specific enough for accurate assessment of the parasites to which a herd may be exposed and is therefore not discussed.Techniques for the diagnosis of the animal trypanosomiases can be divided into parasitological and immunological methods. Those in the process of development in the laboratory and in routine use in the field are assessed in relation to their specificity, the rapidity of the diagnostic method, their reliability and applicability under field conditions. The ideal of a rapid specific parasitological technique may be difficult to attain and local conditions (size of herd; information required by authorities) will determine whatever alternative technique is to be used and which of the criteria (e.g. rapidity, or specificity of diagnosis) should be sacrificed to obtain the required information if time, resources and personnel are limited.     

Evaluation of pleural and peritoneal effusions

Certain diseases cause an increase in the amount of fluid present in the pleural and/or peritoneal cavity (an effusion). Uroperitoneum subsequent to kidney, ureter, bladder, or urethra rupture also can cause an increased amount of fluid in the abdomen. Evaluation of fluid samples often is helpful in identifying the mechanism causing the effusion and, occasionally, results in a specific diagnosis. The TP, TNCC, and general cytologic examination can be performed easily, quickly, and inexpensively in-house. The TP and TNCC are used to classify effusions as transudates, modified transudates, or exudates. Transudates usually are caused by hypoalbuminemia, but also can be caused by leakage of fluid from efferent intestinal lymphatics. Cytology and culture usually are not rewarding in the evaluation of transudates. Modified transudates usually are caused by increased vascular permeability or increased intrahepatic hydrostatic pressure. Cytologic and radiographic examinations often are helpful in evaluating patients with modified transudates, while cultures usually are unrewarding. The exudate class encompasses the inflammatory exudates (septic or nonseptic), neoplastic exudates, and chylous effusions. Inflammatory exudates have a high TP and predominantly contain inflammatory cells. They may be septic or nonseptic. When septic, degeneration neutrophils often, but not always, are found. Cultures often are needed to determine whether sepsis is present, to identify the specific organism, and to determine the best therapy. Neoplastic exudates may contain numerous neoplastic cells. If there is concern that the cells are dysplastic instead of neoplastic, the cytology preparation should be referred to a consultant. Chylous effusions usually contain many small lymphocytes with a variable number of neutrophils and macrophages. In chronic chylous effusions, however, neutrophils and/or macrophages may predominate. Chylous effusions usually are differentiated easily from pseudochylous effusions by cytology. Comparison of fluid and serum triglyceride and cholesterol concentrations can be used to differentiate chylous and pseudochylous effusions when differentiation cannot be accomplished by cytology.     

Diagnostic assessment of peritoneal fluid cytology in horses with abdominal neoplasia

Objective: To evaluate the diagnostic value of peritoneal fluid (PF) cytology for clinical diagnosis of abdominal neoplasia in horses. Material and methods: Ten horses with histopathologically confirmed abdominal neoplasia, in which a PF analysis was performed, were included in this retrospective study. PF was analyzed for total protein concentration and a nucleated cell count was performed. Using cytological criteria of malignancy, the PF samples were evaluated regarding their probability of malignancy. Results: Cytologic classification of cells according to criteria of malignancy allowed a positive cytologic diagnosis of neoplasia in 5 out of 10 peritoneal fluid samples. Malignant lymphoma was the most commonly diagnosed neoplasia (3/10) and could be identified by cytology in 2/3 cases. In 1/2 horses with plasma cell myeloma neoplastic cells were similarly found. Malignant melanoma (2/10) was diagnosed using cytology in one case (presence of melanin-containing cells). Cytological diagnosis of malignant neoplasia was established in the only horse with gastric squamous cell carcinoma, but the morphology of the identified tumour cells did not allow a specific diagnosis. Thus, a definitive diagnosis was achieved in 4/5 horses with proven abdominal neoplasia. The horses with adenocarcinoma (1/10) and haemangiosarcoma (1/10) had no evidence of neoplasia based on cytological findings. No relationship between total protein concentration or the nucleated cell count with the histolopathological diagnosis of abdominal neoplasia was found. Abnormal mitotic figures were considered of greater diagnostic value than the overall mitotic rate. Conclusion: The implementation of nuclear criteria of malignancy in the cytologic evaluation of PF samples allows the identification of neoplastic cells to an acceptable degree. For this purpose, the knowledge of the highly variable morphological features of mesothelial cells is essential. The absence of malignant cells does not rule out abdominal neoplasia. Clinical relevance: PF cytology should be considered as a valuable, minimally invasive, simple, and rapid diagnostic technique in horses with suspected abdominal neoplasia.     

Construction and validation of a risk-screening questionnaire for the investigation of recurrent airway obstruction in epidemiological studies of horse populations in Great Britain

Recurrent airway obstruction (RAO) is an environmental respiratory disease affecting horses. A risk-screening questionnaire (RSQ) for RAO would provide a useful tool to investigate the epidemiology of the disease in horses; our aim in this study was to construct and validate such an instrument. Guidance for what questions to include in the RSQ came from three processes: a review of the scientific literature, a survey of equine practitioners in the UK and a consultation with 19 experts using a modified Delphi technique. The latter consultation consisted of two rounds; agreement amongst the experts increased between the rounds. The quantitative outputs provided estimates of the probabilities of a horse having RAO for each particular piece of historical information or clinical sign. The RSQ for RAO was a short questionnaire for completion by horse owners regarding the horse, its health and its management. The likelihood of a horse having RAO (the RAO score) was calculated from a completed RSQ by combining the relevant estimated probabilities. The RSQ was validated against a reference standard of a veterinary diagnosis including respiratory cytology. This was achieved by inviting veterinary surgeons (residing in Great Britain who had taken part in the practitioner survey, and who had indicated that they used respiratory cytology in the diagnosis of respiratory cases) to participate. During 2003 and 2004 these veterinary surgeons returned RSQs for 40 cases that underwent investigation of the respiratory tract and 40 controls; 18 of the cases were given a final diagnosis of RAO. A receiver-operating characteristic (ROC) curve was used to select a positive cut-off of 0.87 for the RSQ for RAO. This suggested that the RSQ had a sensitivity of 0.83 (95% confidence interval=0.59-0.96) and specificity of 0.85 (0.74-0.93) for the diagnosis of apparent RAO (compared to all other diagnoses).     

一起犊牛真胃穿孔引起腹膜炎的诊治体会

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