Long-term follow-up of a case of feline leishmaniosis treated with a combination of allopurinol and meglumine antimoniate.

A 9-year-old domestic cat, positive for antibodies to feline immunodeficiency virus (FIV), was brought to a veterinary clinic with alopecia, ulcerative skin lesions, and upper respiratory tract (URT) signs. This was after being treated for suspected allergic dermatitis, without clinical improvement, for 2 y. Biopsy of the skin and fine-needle aspirates of the spleen and of the lymph nodes were taken which detected the presence of Leishmania amastigotes. Leishmania infection was further confirmed by detection of a high titer of anti-Leishmania antibodies (≥ 3200) with an indirect fluorescent antibody technique (IFAT) serology. After the diagnosis of feline leishmaniosis (FeL) was made, allopurinol and meglumine antimoniate were started and led to quick and complete clinical improvement. After 7 mo, allopurinol administration was briefly interrupted but was resumed following relapse of the skin lesions. One month later, the cat was treated for suspected acute kidney injury, which prompted reduction of the total daily dose of allopurinol by 50%. The cat remained clinically well, with complete resolution of the cutaneous and URT signs, for nearly 24 mo after the diagnosis of FeL; at which point it was euthanized for worsening cardiac disease. To our knowledge, this represents a rare case of successful treatment of FeL with a suspected nephrotoxic effect associated with long-term use of allopurinol. Further studies are required to clarify the relationship, if any, between leishmaniosis and congestive heart failure in cats.

Suivi à long terme d'un cas de leishmaniose féline traité par une association d'allopurinol et d'antimoniate de méglumine. Un chat domestique de 9 ans, positif pour les anticorps contre le virus de l'immunodéficience féline (FIV), a été présenté dans une clinique vétérinaire avec une alopécie, des lésions cutanées ulcéreuses et des signes des voies respiratoires supérieures (URT). Ceci après avoir été traité pour une suspicion de dermatite allergique sans amélioration clinique, pendant 2 ans. Une biopsie de la peau et des ponctions à l'aiguille fine de la rate et des ganglions lymphatiques ont été réalisées et ont détecté la présence d'amastigotes de Leishmania. L'infection à Leishmania a été confirmée par la détection d'un titre élevé d'anticorps sériques anti-Leishmania (≥ 3200) par une technique d'immunofluorescence indirecte (IFAT). Après le diagnostic de leishmaniose féline (FeL), un traitement à l'allopurinol et l'antimoniate de méglumine a été instauré et a entraîné une amélioration clinique rapide et complète. Après 7 mois, l'administration d'allopurinol a été brièvement interrompue mais a été reprise après la rechute des lésions cutanées. Un mois plus tard, le chat a été traité pour une lésion rénale aiguë suspectée, ce qui a entraîné une réduction de 50 % de la dose quotidienne totale d'allopurinol. Le chat est resté cliniquement en bonne santé, avec une résolution complète des signes cutanés et urinaires, pendant près de 24 mois après le diagnostic de FeL; à quel point il a été euthanasié pour aggravation de la maladie cardiaque.À notre connaissance, ceci représente un cas rare de traitement réussi de FeL avec un effet néphrotoxique suspecté associé à une utilisation à long terme d'allopurinol. D'autres études sont nécessaires pour clarifier la relation, le cas échéant, entre la leishmaniose et l'insuffisance cardiaque congestive chez les chats.(Traduit par Dr Serge Messier).

Cytologic features of reactive fibroplasia in cutaneous and subcutaneous lesions of dogs: A retrospective study.

BACKGROUND: Determining reactive fibroplasia from primary neoplastic proliferation can be difficult using the cytologic features of spindle cells. OBJECTIVES: This study aimed to describe qualitative features of benign reactive spindle cells and provide a diagnostic tool to distinguish between fibroplasia and soft tissue sarcoma. METHODS: Cytologic samples from cutaneous lesions with histopathologically confirmed fibroplasia were reviewed and compared with cytologic samples from confirmed low-grade soft tissue sarcomas. The samples were obtained from the Archive of the Laboratorio Veterinario Bresciano (Brescia; Italy). RESULTS: A total of 25 cytologic samples retrieved from the database fit the selection criteria. For comparison, 25 cytologic samples of histopathologically confirmed soft tissue sarcomas with secondary inflammation were obtained and reviewed from the same database. A low number of singularly distributed spindle cells with mild features of atypia and a high ratio of inflammatory to spindle cells was observed in confirmed cases of fibroplasia. CONCLUSIONS: Low cellularity, individualized spindle cells, and an increased inflammatory-to-spindle cell ratio were more indicative of fibroplasia than sarcoma.

Performance of lymph node cytopathology in diagnosis and characterization of lymphoma in dogs.

BACKGROUND: Cytopathology is a minimally invasive and convenient diagnostic procedure, often used as a substitute for histopathology to diagnose and characterize lymphoma in dogs. OBJECTIVES: Assess the diagnostic performance of cytopathology in diagnosing lymphoma and its histopathological subtypes in dogs. ANIMALS: One-hundred and sixty-one lymph node samples from 139 dogs with enlarged peripheral lymph nodes. METHODS: Based only on cytopathology, 6 examiners independently provided the following interpretations on each sample: (a) lymphoma vs nonlymphoma; (b) grade and phenotype; and (c) World Health Organization (WHO) histopathological subtype. Histopathology and immunohistochemistry (IHC) findings were used as reference standards to evaluate diagnostic performance of cytopathology. Clinical, clinicopathologic, and imaging data also were considered in the definitive diagnosis. RESULTS: Classification accuracy for lymphoma consistently was >80% for all examiners, whereas it was >60% for low grade T-cell lymphomas, >30% for high grade B-cell lymphomas, >20% for high grade T-cell lymphomas, and <40% for low grade B-cell lymphomas. Interobserver agreement evaluated by kappa scores was 0.55 and 0.32 for identification of lymphoma cases, and of grade plus immunophenotype, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Cytopathology may result in accurate diagnosis of lymphoma, but accuracy decreases when further characterization is needed. Cytopathology represents a fundamental aid in identifying lymphoma and can be used as a screening test to predict grade and phenotype. However, these results must be confirmed using other ancillary techniques, including flow cytometry, histopathology, and immunohistochemistry (IHC).

The cytologic features of biliary diseases: A retrospective study.

BACKGROUND: Histologic examination, together with clinical data and instrument support, contributes to the recognition of biliary diseases. Although quantitative and qualitative changes in hepatic and biliary cells can occur, descriptions of cytologic samples from the liver affected by cholangiopathies are rare. OBJECTIVES: This study aimed to describe the quantitative and qualitative changes in cholangiocytes, hepatocytes, and inflammatory cells in cytologic samples from dogs and cats affected by histologically confirmed cholangiopathies. METHODS: Cytologic samples from the liver with histologically confirmed cholangiopathies were reviewed and compared to describe the changes seen on cytology. The samples were obtained from the Archive of Clinica Veterinaria Sant'Antonio and the Laboratorio Veterinario Bresciano. Statistical analysis was not performed. RESULTS: A total of 196 cytologic samples retrieved from the database fit the selection criteria, 88 from dogs, and 108 from cats. A total of eight categories of cholangiopathies have been identified and described, while histology is often required to achieve a definitive diagnosis, six categories of cholangiopathy in dogs and seven in cats provide cytologic information. CONCLUSIONS: Cytologic examination, together with clinical and ultrasonographic data, can be useful for identifying hepatic abnormalities in acute and chronic cholestasis, chronic cholangitis, feline lymphoplasmacytic cholangitis, and cholangiocellular neoplasms.

Role of thyroid transcription factor-1 in the diagnosis of feline lung-digit syndrome.

Objectives The aim of this study was to investigate the role of thyroid transcription factor-1 (TTF-1) in the diagnosis of feline lung-digit syndrome (FLDS) and to investigate the associations between the morphological features of FLDS and TTF-1 expression. We also compared the reliability of TTF-1 and transmission electron microscopy (TEM) in establishing the diagnosis of FLDS. Methods Histology records of feline digit tumours were retrieved, including patients from 2008-2015. If formalin-fixed, paraffin-embedded tissues were available for review, patients were included in the study. As a control group we included 12 feline primary tumours of the digits. All the histological slides of the study group were blindly reviewed by the same veterinary pathologist. Representative sections of the lesions were selected for immunohistochemistry (IHC) analysis. To confirm the respiratory origin of the neoplastic tissue, TEM was used as a gold standard in all cases. Results Five cases of FLDS were included. TTF-1 was weakly to moderately positive in 60% of the cases, showing no correlation with the microscopic presence of ciliated epithelium. When IHC results were combined with the presence of cilia, 80% of the cases from the study group could be identified as FLDS. TEM confirmed the presence of ciliated epithelium in all five cases, confirming the respiratory origin of the neoplastic tissue and therefore the diagnosis of FLDS. Conclusions and relevance TTF-1 expression is maintained in FLDS. While the combination of TTF-1 and identification of cilia confirms FLDS, TEM should be considered in those cases where diagnosis is uncertain and FLDS is suspected.

Cytologic features of hepatic fibrosis in dogs: a retrospective study on 22 cases.

INTRODUCTION: Liver cytology has diagnostic value for the identification of neoplastic and nonneoplastic hepatic diseases. However, so far the diagnosis of fibrotic changes has traditionally been restricted to histopathology. OBJECTIVES: The aim of this study was to describe the cytologic features that may help in the recognition of hepatic fibrosis. MATERIALS AND METHODS: Cytologic smears from the liver of dogs histologically diagnosed with hepatic fibrosis (Group A) were selected and compared to liver smears from dogs without hepatic fibrosis (Group B). A differential count of hepatocytes, spindle cells, mast cells, granulocytes, lymphocytes/plasma cells, and macrophages was documented for each case, and means for the fibrosis and nonfibrosis group were compared. RESULTS: The relative and total numbers of spindle cells and mast cells were significantly higher in the fibrosis group than in the nonfibrosis group. The optimal cutoff point for the spindle cells to hepatocytes ratio was 0.107 (ie, one spindle cell per 10 hepatocytes), with 95.5% sensitivity and 100% specificity for the cytologic diagnosis of hepatic fibrosis. The optimal cutoff point for the ratio mast cells to hepatocytes was 0.04 (ie, 4 mast cells per 100 hepatocytes) with 86.4% sensitivity and 90% specificity. DISCUSSION: The presence of relatively and absolutely increased numbers of spindle and mast cells in hepatic cytology provides a rational basis to identify fibrosis of hepatic parenchyma. Based on a reasonable sensitivity and specificity, the cytologic diagnosis of hepatic fibrosis seems feasible.

Characterization of cytoplasmic hyaline bodies in a hepatocellular carcinoma of a dog.

This report describes the morphological and immunohistochemical features of intracytoplasmic inclusion bodies found in a 13-year-old Yorkshire dog with a hepatocellular carcinoma and referred for anorexia, lethargy and mild polydipsia. Fine-needle aspirates of the large abdominal mass revealed high number of pleomorphic neoplastic hepatocytes, containing round to polygonal, well-demarcated, hyaline bodies. Same findings were histologically confirmed on multiple biopsies. Immunohistochemically, the inclusion bodies were negative for alpha-1-antitrypsin, carcinoembryonary antigen, fibrinogen, IgG, IgM, cytokeratins 7, 8, 18, 19, 20. By transmission electron microscopy, the cytoplasmic inclusions were composed of granular homogeneous or reticulated electrondense matrix, enclosed within dilated rough endoplasmic reticulum or remnants of its membranes, consistent with proteinaceous material accumulated within neoplastic hepatocytes due to aberrant protein secretion or transport. This is the first detailed characterization of hyaline cytoplasmic inclusion bodies in canine hepatocellular carcinoma.

Proportion of mast cells in normal canine hepatic cytologic specimens: comparison of 2 staining methods.

BACKGROUND: Although the presence of mast cells is considered a normal finding in canine hepatic tissue, the normal proportion of these cells in cytologic specimens from normal livers was not previously established. OBJECTIVES: The objective of this study was to determine the normal proportion of hepatic mast cells in cytologic specimens from normal canine liver by the use and comparison of the May-Grünwald-Giemsa and the Toluidine Blue staining methods. METHODS: The cytologic specimens obtained from fine-needle aspirates of livers of 13 healthy dogs were investigated by counting of hepatocytes and mast cells per high-power field (HPF, x40 objective). The ratio of mast cells/100 hepatocytes was then compared between the 2 staining methods. RESULTS: A median of 0.17 (range: 0-0.33) mast cells/100 hepatocytes and of 0.47 (range: 0-0.86) mast cells/100 hepatocytes was obtained with May-Grünwald-Giemsa and Toluidine Blue stains, respectively. CONCLUSIONS: Toluidine Blue stain detects more hepatic mast cells than May-Grunwald-Giemsa in normal canine livers. With both stains, < 1% mast cells were detected in normal canine liver samples.

Cytologic features of normal canine ovaries in different stages of estrus with histologic comparison.

BACKGROUND: Cytologic evaluation plays an important role in the diagnosis of ovarian neoplasia in dogs, but is supported by only scant information on cytologic features of canine ovaries. OBJECTIVE: The aim of this study was to provide detailed cytologic descriptions of normal canine ovaries in different stages of estrus with comparison to histologic features. METHODS: Client-owned dogs admitted for elective ovariohysterectomy were studied. For each dog, fine-needle aspirates of both ovaries were collected, stained, and examined and were compared with histologic sections of the same ovary. The stage of estrus was confirmed by examination of histologic sections and cytologic specimens of vaginal cells collected with swabs. RESULTS: Thirty-two ovaries from 16 dogs were examined. Luteal cells were observed in 82% of the dogs in diestrus. In early diestrus these cells were polygonal with amphophilic to deeply basophilic cytoplasm, and in late diestrus luteal cells had blebbed cell borders and clear cytoplasm with numerous small vacuoles. Perivascular arrangements and leuko-emperipolesis were noted in both phases of diestrus. Granulosa cells and spindle cells were found in cytologic specimens from most of the ovaries, and blue-gray extracellular material, sometimes associated with granulosa cells, was present. Medium-sized discrete round cells of undetermined origin were observed in some stages of estrus, and structures classified as corpora albicans were noted occasionally. CONCLUSIONS: Knowledge of specific cytologic features of normal canine ovaries is important for identification of pathologic processes in this organ. The novel findings of luteal cell emperipolesis, extracellular material associated with granulosa cells, and round cells of undetermined lineage warrant further study, which may provide new information on canine ovarian structure and function.

Retrospective study of cytologic features of well-differentiated hepatocellular carcinoma in dogs.

BACKGROUND: Cytologic diagnosis of hepatocellular carcinoma is possible when hepatocytes have prominent criteria of malignancy, but is problematic when hepatocytes have a relatively normal morphologic appearance. OBJECTIVES: The aim of this study was to determine the cytologic features of histologically confirmed well-differentiated hepatocellular carcinomas (WD-HCC) in dogs to develop reasonable criteria for an accurate diagnosis when obvious criteria of malignancy in hepatocytes are lacking. METHODS: Slides of ultrasound-guided fine-needle aspirates of 15 histologically confirmed WD-HCC in dogs were evaluated retrospectively using a scoring system (0-3) established for 33 cytologic features. For comparison, 15 cytologic samples of non-nodular non-neoplastic liver were evaluated using the same criteria. Statistical analysis included multiple hypothesis testing using the Benjamini-Hochberg method or false discovery rate control to correct for multiple comparisons. RESULTS: The most significant and useful cytologic features in the diagnosis of canine WD-HCC were dissociation of hepatocytes, acinar or palisading arrangements of neoplastic cells, and the presence of naked nuclei and capillaries, together with mild anisocytosis, anisokaryosis, multinuclearity, and increased N:C ratios. CONCLUSIONS: Cytologic features of canine WD-HCC were determined. Further studies are warranted to compare these cytologic criteria among WD-HCC, hepatomas, and hyperplastic nodules and to examine co-variance of the 33 cytologic features.

Cytologic, histologic, and immunohistochemical features of lingual liposarcoma in a dog.

A 9-year-old female spayed mixed-breed dog was presented to the referring veterinarian with a history of decreased appetite and difficulty with prehension and swallowing because of a firm oval mass in the tongue. On cytologic evaluation of a fine-needle aspirate of the mass there were numerous round to polygonal cells organized individually or in loose clusters with rare branching capillaries. The cells had eosinophilic granular cytoplasm, round to oval nuclei, and occasionally indistinct borders. The cytologic diagnosis was granular cell tumor (GCT) of the tongue. Impression smears of a biopsy sample of the lingual mass contained similar eosinophilic granular cells with variable numbers of clear vacuoles in the background, numerous perivascular arrangements, and occasional lipoblasts, suggestive of liposarcoma. On histologic examination the tumor was composed of numerous lipocytes with rare foci of round eosinophilic granular cells without evidence of vacuolation; occasionally, atypical mitotic figures were seen. Immunohistochemically, the cells were uniformly negative for periodic acid-Schiff and did not express smooth muscle actin, desmin, or cytokeratin but were immunoreactive for vimentin and S100. A diagnosis of well-differentiated liposarcoma was made on the basis of morphologic and immunohistochemical results. Eosinophilic granular cells may be a component of well-differentiated liposarcoma and are not limited to GCT. Liposarcoma should be considered in the differential diagnoses of lingual tumors in the dog when cytological evaluation reveals eosinophilic granular cells consistent with GCT.

Differential cell counts in canine cytocentrifuged bronchoalveolar lavage fluid: a study on reliable enumeration of each cell type.

BACKGROUND: Bronchoalveolar lavage (BAL) allows cell recovery from the lower respiratory tract; differential cell counts of BAL fluid gives important information in the assessment of various bronchial and pulmonary diseases. To the best of our knowledge no study has investigated the relation between the number of cells counted and the reproducibility of BAL fluid differential cell counts. OBJECTIVE: The purpose of this study was to investigate using statistical methods how many cells should be counted in cytocentrifuged BAL fluid preparations in order to obtain a reliable enumeration of each cell type. METHODS: BAL fluid samples from dogs with suspected bronchopulmonary disease were obtained during fiberoptic bronchoscopy with a standardized protocol. Differential cell counts were performed on May-Grünwald-Giemsa-stained cytocentrifuged preparations by 2 independent observers. Reproducibility for the enumeration of each cell type was expressed as the intraclass correlation coefficient. We considered a threshold level of >or=0.90 to be high and a threshold level of >or=0.85 to be adequate. RESULTS: Forty BAL fluid samples were included in the study. For neutrophils, alveolar macrophages, and eosinophils high reproducibility was reached by counting 200 cells; adequate reproducibility was reached for lymphocytes and bronchial epithelial cells by counting 500 cells. CONCLUSIONS: A 500-cell differential count is required for all types of cells to be quantified with adequate reproducibility in canine cytocentrifuged BAL fluid samples.

Unusual "erythroid loops" in canine blood smears after viper-bite envenomation.

Northern Italy is a habitat for many species of viper; Vipera aspis is responsible for most reported bites of humans and animals. Five dogs of different breeds and ages were presented by their owners to a veterinary clinic in northern Italy between September 2004 and August 2007 with a history of being bitten by a viper within the past 2 hours. On physical examination, all of the dogs were depressed, had pale mucous membranes, and had a painful area consistent with a recent viper bite wound on the nose (2), distal front leg (2), or lip (1). Hemoglobinemia and hemoglobinuria were observed in plasma and urine from all dogs. CBCs were done at the time of presentation, daily for 4 days, and 10 days after presentation in all dogs with the exception of one dog that died after 2 days. All dogs had an acute decrease in HCT within 24 hours of presentation; all dogs had neutrophilia, 3/5 had a mildly toxic left shift, and 4/5 had thrombocytopenia. On Diff-Quik-stained blood smears, moderate numbers of echinocytes, spherocytes, and erythrocyte ghosts were observed. In addition, moderate numbers of unusual erythrocyte membrane-like structures ("erythroid loops") were observed. The loops were annular in shape and sometimes disrupted, appearing as thin pale blue bands. Erythrocyte morphologic abnormalities decreased by day 3 and were no longer observed on day 10. The unique appearance of the erythroid loops together with evidence for intravascular hemolysis and other erythrocyte morphologic changes suggest they may be a consequence of erythrocyte lysis. Echinocytes, spherocytes, and erythrocyte ghosts are known to result from the action of phospholipase in viper venom; however, erythroid loops have not been reported previously and their exact mechanism of formation is unknown.

Cytologic detection of Call-Exner bodies in Sertoli cell tumors from 2 dogs.

A 14-year-old Italian Griffon and an 11-year-old mixed breed dog were presented to our clinic with monolateral testicular enlargement. In both dogs, a firm, nodular, and nonpainful mass was palpated, and ultrasonographic examination of testicular parenchyma showed a large and irregular nodular area with hyperechogenic features. Fine-needle aspirates of the masses were highly cellular and consisted of populations of large elongated vacuolated cells in sheets and palisades, with finely granular chromatin and prominent nucleoli, consistent with neoplastic Sertoli cells. A variable number of structures also were observed that consisted of a central round area of amorphous, deeply eosinophilic, hyaline material surrounded by a peripheral, rosette-like arrangement of single or multiple rows of Sertoli cells. These structures were suggestive of Call-Exner bodies. Histologic sections of the tumors obtained following castration confirmed the diagnosis of Sertoli cell neoplasia and the presence of Call-Exner bodies. The Call-Exner bodies were intensely positive with PAS, toluidine blue, and Ziehl-Neelsen stains, moderately positive with alcian blue, and negative with Congo red and Luxol fast blue. Call-Exner bodies, thought to represent an attempt by neoplastic cells to form basement membrane, are seen most frequently in granulosa cell tumors, but are occasionally reported in testicular tumors that contain epithelial elements of sex-cord origin. To our knowledge, this is the first description of Call-Exner bodies in cytologic specimens from dogs, and only the fifth report of their presence in canine testicular neoplasms.

Architectural patterns in cytology: correlation with histology.

Cellular arrangements are highly relevant in the evaluation of histologic sections, but cytologic specimens are not thought to accurately reflect the same patterns. Only occasionally do cytologic descriptions comprise, apart from cytoplasmic and nuclear features, architectural patterns. Architectural arrangement of cells in cytologic specimens, however, may mirror the corresponding arrangement of cells in histologic specimens provided the cytologic preparations are collected and prepared appropriately. Recognition and understanding of the different types of cell arrangements that may be seen in cytologic specimens can provide important information for obtaining a definitive diagnosis, particularly for neoplastic lesions. The goal of this review is to describe the most common architectural patterns observed in cytologic specimens and to draw correlations with similar histologic arrangements.

Diagnostic value of cytologic examination of gastrointestinal tract tumors in dogs and cats: 83 cases (2001-2004).

OBJECTIVE: To determine results of cytologic examination of fine-needle aspirates and impression smears of gastrointestinal tract tumors in dogs and cats. DESIGN: Retrospective case series. ANIMALS: 38 dogs and 44 cats with histologically confirmed gastrointestinal tract tumors. PROCEDURES: Results of cytologic examination of fine-needle aspirates (n = 67) or impression smears (31) were compared with the histologic diagnosis, and extent of agreement was classified as complete, partial, none, or undetermined. RESULTS: For 48 of the 67 (72%) fine-needle aspirates, there was complete or partial agreement between the cytologic and histologic diagnoses. For 12 (18%) aspirates, the extent of agreement could not be determined because the cytologic specimen was considered unsatisfactory. For 29 of the 31 (94%) impression smears, there was complete agreement between the cytologic and histologic diagnoses, and for 2 (6%), there was partial agreement. None of the impression smears were considered unsatisfactory. Proportion of samples with complete agreement and proportion of samples with complete or partial agreement were significantly higher for impression smears than for fine-needle aspirates. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that there was moderate agreement between results of cytologic examination of fine-needle aspirates from dogs and cats with gastrointestinal tract neoplasia and the definitive histologic diagnosis. The agreement between results of cytologic examination of impression smears and the histologic diagnosis appeared to be higher.

Squash-prep cytology in the diagnosis of canine and feline nervous system lesions: a study of 42 cases.

BACKGROUND: The increased sophistication of imaging techniques in veterinary medicine allows the detection of a wide variety of intracranial and intraspinal lesions; however, imaging often does not provide a definitive diagnosis for nervous system (NS) lesions. Cytology is emerging as a useful diagnostic tool for obtaining a fast and accurate assessment of NS lesions, but little information is available for dogs and cats. OBJECTIVES: The purpose of this study was to assess the accuracy of cytologic evaluation of squash samples from NS lesions in dogs and cats and to consider cytology-based diagnostic guidelines and sources of misdiagnosis. METHODS: Cytologic specimens from masses localized in the central and peripheral NS taken during surgery or postmortem examination were classified into 3 groups according to the final histopathologic diagnosis: Group 1 = completely correct diagnosis, when the cytologic diagnosis and final histologic diagnosis were exactly correlated; Group 2 = partial correlation, when the cytologic diagnosis only partially correlated with the final histologic diagnosis, and Group 3 = no correlation, when the cytologic diagnosis was incorrect and there was no correlation with the general histologic type of lesion. The diagnostic accuracy of cytopathology was calculated by considering the histopathologic diagnosis as the "gold standard," and calculating a 95% confidence interval (CI). RESULTS: A total of 42 animals (33 dogs and 9 cats) were included in the study. The cytologic diagnoses were classified in Group 1 for 32 cases (76%; 95% CI 0.63-0.89), in Group 2 for 6 cases (14%; 95% CI 0.04-0.25), and in Group 3 for 4 cases (10%; 95% CI 0.006-0.18). Considering both complete and partial correlation as an adequate result, cytologic diagnosis was satisfactory in 90% of biopsies. CONCLUSIONS: Although the current series of cases is relatively small, cytologic evaluation of squash preparations can be considered a fairly accurate and reliable tool in the diagnosis of NS lesions.