Cytologic evaluation of inflammation in canine liver aspirates

Abstract: Liver aspiration cytology has been used routinely for more than a decade for the evaluation of canine and feline liver disease. However, the value of liver cytology in detecting inflammatory liver disease is poorly defined. We retrospectively reviewed 51 canine liver cytology reports and compared the conclusions with those from concurrent surgical biopsy reports. Overall sensitivity of cytology for diagnosis of inflammatory liver disease was 93% and specificity was 96%. For suppurative hepatitis (n = 14), the sensitivity of cytologic diagnosis was 100% and the specificity was 95%. For chronic active hepatitis (n = 13), the sensitivity of cytologic diagnosis was 100% and the specificity was 93%. For lymphocytic hepatitis (n = 3), the sensitivity of cytologic diagnosis was 33% and the specificity was 100%. We conclude that canine liver aspiration cytology is a highly sensitive test for the detection of suppurative and chronic active inflammation; however, it is insensitive for the detection of lymphocytic hepatitis.     

Usefulness of Ki-67 proliferation marker in the cytologic identification of liver tumors in dogs

BACKGROUND: Performing a biopsy is currently the best method of diagnosing liver disease. To reduce possible risk factors resulting from a biopsy, liver cytology can provide an alternative technique. The diagnostic accuracy of cytology for identifying liver tumors is, however, limited. The results of cytology might be improved by using immunochemistry for Ki-67, a proliferation marker, on liver cytology specimens. OBJECTIVES: The purpose of this study was to investigate the value of Ki-67 immunochemistry on liver cytologic specimens from dogs for identifying neoplastic diseases of the liver, by comparing the results to histologic findings. METHODS: Liver biopsy and cytology samples were obtained from 30 dogs with hepatic disease. All samples were evaluated by an anatomic pathologist and a cytopathologist. Parallel Ki-67 immunochemistry of histologic and cytologic samples was performed. The gradation of Ki-67 expression in histologic and cytologic samples was assessed. RESULTS: Cytologic specimens of liver tumors (n = 9) showed <50% Ki-67-positive cells. Twenty of 21 cases of non-neoplastic liver disease had no or few single Ki-67-positive cells. Using Ki-67, the diagnostic accuracy of cytologic evaluation was increased from 78% to 100% for malignant neoplasia. CONCLUSIONS: Based on the results of this study, the cytologic evaluation of liver together with Ki-67 immunochemistry can improve the diagnostic accuracy of cytology for liver neoplasia.     

Accuracy of ultrasound-guided fine-needle aspiration of the liver and cytologic findings in dogs and cats: 97 cases (1990-2000)

OBJECTIVE: To evaluate the accuracy of ultrasound-guided fine-needle aspiration of the liver and cytologic findings in dogs and cats. DESIGN: Retrospective study. ANIMALS: 56 dogs and 41 cats. PROCEDURE: Medical records of dogs and cats evaluated from 1990 to 2000 by use of cytologic and histopathologic examination of the liver were reviewed. Histologic and cytologic diagnoses were categorized as vacuolar hepatopathy, inflammation, neoplasia, cirrhosis, primary cholestasis, shunt, normal, and other. RESULTS: Overall agreement between the histopathologic diagnosis and cytologic diagnosis was found in 17 of the 56 (30.3%) canine cases and 21 of the 41 (51.2%) feline cases. Vacuolar hepatopathy was the category with the highest percentage of agreement. Vacuolar hepatopathy was identified via cytologic examination in 7 of 11 and 15 of 18 dogs and cats, respectively, in which histopathologic examination revealed that it was the predominant disease process. However, it was also the category that was most commonly misdiagnosed via cytologic examination. Inflammatory disease was accurately identified cytologically in 5 of 20 and 3 of 11 dogs and cats, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Acknowledging the limitations of cytology and the extent of discrepancies between cytologic and histopathologic findings in dogs and cats will help clinicians make better decisions in diagnosing liver disease.     

Evaluation of sensitivity and specificity of cytologic examination: 269 cases (1999-2000)

OBJECTIVE: To determine sensitivity and specificity of cytologic examination used in a clinical setting. DESIGN: Retrospective study. ANIMALS: 216 dogs, 44 cats, 4 horses, 2 ferrets, 1 llama, 1 rat, and 1 mouse. PROCEDURE: Records were reviewed of cases in which a cytologic diagnosis was followed by a surgical biopsy or postmortem examination within 3 days with subsequent histopathologic diagnosis. Diagnoses were compared for agreement at various levels, including complete agreement, partial agreement, no agreement, or no comparison possible because of insufficient or incorrect cytologic specimen. Levels of agreement were compared for different categories of lesions, including neoplastic, inflammatory, dysplastic-hyperplastic-other, and normal tissue. Additionally, levels of agreement for neoplastic lesions were categorized with regard to cell type, degree of malignancy, and location. Sensitivity and specificity of cytologic examination were calculated. RESULTS: At the level of general agreement (complete and partial agreement), the sensitivity of cytologic examination ranged from 33.3 to 66.1%, depending on the location of the lesion. Cytologic examination was most accurate when used to diagnose cutaneous and subcutaneous lesions and least accurate for diagnosis of liver lesions. Cytologic examination was most effective in diagnosis of neoplastic disease and least effective in diagnosis of dysplastic or hyperplastic conditions. CONCLUSIONS AND CLINICAL RELEVANCE: Cytologic examination is a valuable diagnostic tool, although our results indicated lower accuracy than previously reported. False-negative results (missing a diagnosis) were far more common than false-positive results (categorizing a healthy animal as diseased): therefore, if the clinical index of suspicion is high, cytologic examination should be repeated or another technique should be selected to rule out the suspected condition.     

Correlation between fine-needle aspiration cytology and histopathology in the evaluation of cutaneous and subcutaneous masses from dogs and cats

BACKGROUND: Fine-needle aspiration cytology (FNAC) is commonly used as a diagnostic procedure to evaluate superficial and deep masses in animals. However, few studies have addressed the accuracy of FNAC in the evaluation of cutaneous and subcutaneous masses in a clinical setting. OBJECTIVE: The purpose of this study was to compare the accuracy of FNAC as compared with histopathology in the diagnosis of cutaneous and subcutaneous masses from dogs and cats. METHODS: Cytologic and histopathologic specimens obtained between 1999 and 2003 from 292 palpable cutaneous and subcutaneous masses obtained from 242 dogs and 50 cats were retrospectively evaluated. Cytologic samples were obtained by FNA and histopathologic samples were collected by surgical biopsy or at necropsy. Concordance was determined and the accuracy of FNAC for the diagnosis of neoplasia was determined using histopathology as the gold standard. RESULTS: Of 292 specimens, 49 (from 44 dogs and 5 cats) were excluded due to poor cellularity of the cytologic specimen (retrieval rate 83.2%, n = 243). A cytologic diagnosis of neoplasia was obtained in 176 cases (175 true positives and 1 false positive compared with histopathology). Sixty-seven cytology samples were classified as non-neoplastic (46 true negatives, 21 false negatives compared with histopathology). Overall, the cytologic diagnosis was in agreement with the histopathologic diagnosis in 90.9% (221/243) of cases. For diagnosing neoplasia, cytology had a sensitivity of 89.3%, a specificity of 97.9%, a positive predictive value of 99.4%, and a negative predictive value of 68.7%. CONCLUSIONS: The results of this study confirmed FNAC as a reliable and useful diagnostic procedure for the evaluation of palpable cutaneous and subcutaneous lesions in small animal practice.     

A retrospective study of non-specific rhinitis in 22 cats and the value of nasal cytology and histopathology

Case records from 40 cats subjected to rhinoscopic examination for investigation of chronic nasal disease were reviewed. Cases in which no specific underlying cause (eg neoplasia) was detected were further selected for detailed retrospective study. In these 22 cats (55% of the initial population), a final diagnosis of non-specific chronic nasal disease was made. The radiographic, rhinoscopic, cytological and histopathological findings were reviewed. Mucosal biopsy specimens were obtained in 20 cases. Despite clinical signs of more than 4 weeks duration, histopathology indicated acute inflammation in four cases. Two cases had chronic lymphoplasmacytic inflammation and 14 had mixed (lymphoplasmacytic and neutrophilic) inflammation. Specimens for cytology were obtained from 17 cases by brush sampling. Three of these samples were not diagnostic due to the poor quality of the slides; one showed normal cytology. Acute inflammation was diagnosed by cytology (n=11) more commonly than chronic (n=1) or mixed inflammation (n=1). Concurrent samples, of quality suitable for both histopathological and cytological interpretation, were collected from 12 cases only. Cytological results were in agreement with the histological results in 25% of these cases, the main discrepancy being the nature of the dominant inflammatory cell type. Therefore cytology does not appear to be a reliable means for detection of chronic inflammation. Further studies are needed in order to investigate the correlation between the nature of mucosal inflammation as defined by both histological and cytological evaluation, and the relationship of these test results to prognosis and therapy.     

Basics of cytology and fluid cytology.

Cytology as a diagnostic tool has played a major role in the management of diseases affecting domestic mammals for over 20 years. It has also become a valuable diagnostic tool in the evaluation of nondomestic or the so-called "exotic" animal patients, such as small mammals and the lower vertebrates. Common cytologic specimens used to evaluate the exotic animal patient include aspirates of masses and organs, imprints of biopsy material, tracheal wash samples, aspiration of abdominal or coelomic fluid, and fecal smears. In general, the same cytologic sample collection and preparation techniques used for domestic mammals also apply to exotic animal patients. The interpretation of the cytology specimen is generally the same as that of domestic mammals.     

Canine angiosarcoma: cytologic, histologic, and immunohistochemical correlations

BACKGROUND: Angiosarcomas (AS) are malignant tumors that arise from vascular endothelial cells and are common in dogs. Histologically, AS are markedly heterogeneous neoplasms that make interpretation by cytology difficult. OBJECTIVE: Our objective was to evaluate the cytologic features of canine AS and look for additional diagnostic criteria. METHODS: Cytologic specimens from 19 histologically and immunohistochemically confirmed cases of canine AS were extensively reviewed for cytologic features. We compared cytologic, histopathologic, and immunohistochemical findings. RESULTS: Neoplastic cells in 14 cytology specimens had a high-grade sarcomatous appearance, whereas in 4 specimens the cells were extremely pleomorphic, ranging from sarcomatous to epithelioid. In the remaining case, the neoplastic cells were low grade, spindle shaped, and monomorphic. Other relevant cytologic findings were blood contamination (18/19 cases), cellular cohesiveness (16/19), punctate cytoplasmic vacuolation (19/19), background neutrophilia (11/19) and eosinophilia (5/19), erythrophagocytosis (8/19), extramedullary hematopoiesis (8/19), and apoptotic leukocytes (14/19). Vasoformative features (ie, pseudoacinar structures) were observed in 7 of 19 samples. Histologically, 16 neoplasms had a proliferative pattern typical of well-differentiated canine AS. Three tumors were atypical poorly differentiated AS; 2 of these had a striking epithelioid pattern and 1 was a poorly differentiated spindle cell tumor with focal vascular differentiation. Immunohistochemically, tumor cells in 16 cases were positive for both endothelial markers tested (Factor VIII-related antigen [FVIII-ra] and CD31 antigen), 2 were positive for CD31 only, and 1 was positive for FVIII-ra only. The epithelioid AS were negative for cytokeratins. CONCLUSIONS: The cytologic characteristics of canine AS are widely heterogeneous, but supplementary findings can provide clues that are useful for making a cytologic diagnosis. Histologic and immunohistochemical confirmation is nonetheless warranted in all cases.     

Correlation of ultrasonographic appearance of lesions and cytologic and histologic diagnoses in splenic aspirates from dogs and cats: 32 cases (2002-2005)

OBJECTIVE: To determine the accuracy of cytologic diagnosis, compared with histologic diagnosis, in determination of disease in ultrasound-guided fine-needle aspirates of splenic lesions. DESIGN: Retrospective study. SAMPLE POPULATION: Splenic specimens from 29 dogs and 3 cats. PROCEDURES: Records were searched for dogs and cats that had undergone ultrasound-guided splenic aspiration. Criteria for inclusion were ultrasonographic identification of splenic lesions and cytologic and histologic evaluation of tissue from the same lesion. Cytologic samples were obtained by fine-needle aspiration, and histologic specimens were obtained via surgical biopsy, ultrasound-guided biopsy, or necropsy. RESULTS: Cytologic diagnoses corresponded with histologic diagnoses in 19 of 31 (61.3%) cases and differed in 5 of 31(16.1%) cases, and 1 aspirate was inadequate for evaluation. In 7 of 31 (22.6%) cases, histologic evaluation of tissue architecture was required to distinguish between reactive and neoplastic conditions. On the basis of histologic diagnosis in 14 animals with nonneoplastic conditions, the cytologic diagnosis was correct in 11 cases, not definitive in 2 cases, and incorrect in 1 case. In 17 animals with malignant neoplastic diseases, the cytologic diagnosis was correct in 8 cases, not definitive but consistent with possible neoplasia in 5 cases, and incorrect in 4 cases. Multiple similar-appearing nodules were significantly associated with malignancy, whereas single lesions were more often benign. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasound-guided aspiration of splenic lesions is a minimally invasive tool for obtaining specimens for cytologic evaluation. Although cytologic diagnoses often reflect histologic results, if missampling or incomplete sampling occurs or tissue architecture is required to distinguish between reactive and neoplastic conditions, accurate diagnosis with fine-needle aspiration may not be possible.     

A multistep approach in the cytologic evaluation of liver biopsy samples of dogs with hepatic diseases

Cytologic criteria were evaluated for their diagnostic value in liver disease in dogs. Therefore, histopathologic and cytologic examination was performed on liver biopsy samples of 73 dogs with liver diseases and 28 healthy dogs. Logistic regression analysis was used to select the measured parameters to be included in a multistep approach. With the logistic regression method, different characteristic cytologic parameters could be defined for each histopathologic diagnosis. In malignant lymphoma of the liver, the presence of large numbers of lymphoblasts with a minimum of 5% of all cells was found. Clusters of epithelial cells with several cytologic characteristics of malignancy intermixed with normal hepatocytes were indicative of metastatic carcinoma or cholangiocellular carcinoma. Liver cells in hepatocellular carcinoma were characterized by a high nucleus/cytoplasm ratio, large cell diameters, increased numbers of nucleoli per nuclei, small numbers of cytoplasmic vacuoles, and frequently, small numbers of lymphocytes. Extrahepatic cholestasis was characterized by excessive extracellular bile pigment in the form of biliary casts, an increased number of nucleoli within hepatocytes, decreased hepatic cell size, and low numbers of lymphocytes. In destructive cholangiolitis, increased numbers of neutrophils and a small mean nuclear size within hepatocytes were seen. Acute and nonspecific reactive hepatitis are diagnosed based on the presence of moderate reactive nuclear patterns, including more pronounced chromatin, prominent nucleoli, increased numbers of inflammatory cells, excluding lymphocytes, and the absence of increased numbers of bile duct cell clusters. Increased number of mast cells also was indicative of nonspecific reactive hepatitis. Important cytologic criteria for the diagnosis of liver cirrhosis, in addition to chronic hepatitis, are intracellular bile accumulation and increased numbers of bile duct cell clusters. In summary, the stepwise approach based on logistic regression presented in this study might be helpful in the objective cytologic diagnosis of hepatic diseases.     

Evaluation of rhinoscopy and rhinoscopy-assisted mucosal biopsy in diagnosis of nasal disease in dogs: 119 cases (1985-1989).

The case records of 149 dogs examined from 1985 to 1989 with clinical signs of nasal disease were reviewed. Gross rhinoscopy was performed in 119 dogs, and rhinoscopy-assisted pinch biopsy was performed in 109. Rhinoscopy was performed by use of a 2.7-mm rigid fiberoptic endoscope. Mucosal biopsy specimens were obtained with rhinoscopic guidance by use of a 2 x 3-mm biopsy forcep. Gross, cytologic, and histologic findings are summarized. Ninety-four of 119 cases could be evaluated on the basis of diagnostic and follow-up criteria established by the authors. The diagnostic success rate of gross rhinoscopy with rhinoscopy-assisted biopsy was 83% (78 of 94 evaluated cases). Protracted hemorrhage was a complication in 2 of 109 cases in which rhinoscopy-assisted biopsy was performed. It was concluded that rhinoscopy with rhinoscopy-assisted biopsy contributes important diagnostic information in dogs with nasal disease without the relative invasiveness, expense, and risk of surgery.     

Comparison of results of thoracic radiography, cytologic evaluation of bronchoalveolar lavage fluid, and histologic evaluation of lung specimens in dogs with respiratory tract disease: 16 cases (1996-2000)

OBJECTIVE: To compare results of thoracic radiography, cytologic evaluation of bronchoalveolar lavage (BAL) fluid, and histologic evaluation of biopsy and necropsy specimens in dogs with respiratory tract disease and to determine whether histologic evaluation provides important diagnostic information not attainable by the other methods. DESIGN: Retrospective study. ANIMALS: 16 dogs. PROCEDURE: BAL fluid was classified as normal, neutrophilic, eosinophilic, mononuclear, mixed, neoplastic, or nondiagnostic. Radiographic abnormalities were classified as interstitial, bronchial, bronchointerstitial, or alveolar. Histologic lesions were classified as inflammatory, fibrotic, or neoplastic, and the predominant site of histologic lesions was classified as the alveoli, interstitium, or airway. RESULTS: The predominant radiographic location of lesions correlated with the histologic location in 8 dogs. Of 11 dogs with histologic evidence of inflammatory disease, 8 had inflammatory BAL fluid. Of the 2 dogs with histologic evidence of neoplasia, 1 had BAL fluid suggestive of neoplasia, and the other had BAL fluid consistent with septic purulent inflammation. Two dogs without any histologic abnormalities had mononuclear or nondiagnostic BAL fluid. Two dogs with histologic evidence of fibrosis had mononuclear or mixed inflammatory BAL fluid. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that although thoracic radiography, cytologic evaluation of BAL fluid, and histologic evaluation of lung specimens are complementary, each method has limitations in regard to how well results reflect the underlying disease process in dogs with respiratory tract disease. Lung biopsy should be considered in cases where results of radiography and cytology are nondiagnostic.     

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.     

Use of the argyrophilic nucleolar region method for cytologic and histologic examination of the lymph nodes in dogs

Argyrophilic nucleolar organizer region (AgNOR) counts in cytologic and histologic lymph node samples from healthy dogs and dogs with lymphoma were compared. Control samples were taken from 10 Beagle dogs (six female and four male dogs, 1.5-2 years), and lymphoma samples were taken from 16 dogs. Cytologic samples were obtained by fine-needle aspiration and impression and histologic samples by excision or incisional biopsy. Altogether, 26 cytologic, 19 excisional, and 7 incisional biopsy samples were examined. Lymph nodes of controls showed a moderate inflammatory pattern; of the lymphoma cases, nine were low-grade forms and seven were high-grade forms. Mean AgNOR counts per nucleus were determined. AgNOR counts were statistically different (P < 0.001) between controls and lymphoma cases in cytologic (1.35 and 3.59, respectively) and histologic (1.4 and 2.89, respectively) samples. In lymphoma cases, AgNOR counts in cytologic samples were higher than those in histologic samples by 0.81 (P < 0.001) and showed a linear relationship (r = 0.6; P < 0.05) with the histologic counterparts in excisional biopsy samples. AgNOR counts in low- and high-grade lymphomas were significantly different (P < 0.05) in cytologic (3.21 and 4.08, respectively) and histologic (2.68 and 3.18, respectively) samples. In conclusion, AgNOR counts were higher in lymph nodes with lymphoma than in reactive nodes. In the case of dogs with lymphoma, AgNOR counts in cytologic samples were linearly related to excisional but not to incisional biopsy samples. Although AgNOR counts were different between cytologic and histologic samples, either sample type provided enough sensitivity to differentiate between high- and low-grade forms of lymphoma.     

Evaluation of an endoscopic liver biopsy technique in green iguanas

OBJECTIVE: To establish a safe and effective endoscopic technique for collection of liver biopsy specimens from lizards by use of a 2.7-mm rigid endoscope system that is commonly available in zoologic veterinary practice. DESIGN: Prospective study. ANIMALS: 11 subadult male green iguanas (Iguana iguana). PROCEDURES: Each lizard was anesthetized, and right-sided coelioscopic examination of the right liver lobe and gallbladder was performed. Three liver biopsy specimens were collected from each lizard by use of a 2.7-mm rigid endoscope and 1.7-mm (5-F) biopsy forceps. Biopsy samples were evaluated histologically for quality and crush artifact. Ten days following surgery, all iguanas were euthanatized and underwent full necropsy examination. RESULTS: For all 11 iguanas, the right liver lobe and gallbladder were successfully examined endoscopically, and 3 biopsy specimens of the liver were collected without complications. Mean +/- SD durations of anesthesia and surgery were 24 +/- 7 minutes and 6.8 +/- 1.0 minutes, respectively. At necropsy, there was no evidence of trauma or disease associated with the skin or muscle entry sites, liver, or any visceral structures in any iguana. All 33 biopsy specimens were considered acceptable for histologic interpretation; in most samples, the extent of crush artifact was considered minimal. CONCLUSIONS AND CLINICAL RELEVANCE: By use of a 2.7-mm rigid endoscope, liver biopsy procedures can be performed safely, swiftly, and easily in green iguanas. Biopsy specimens obtained by this technique are suitable for histologic examination. For evaluation of the liver and biopsy specimen collection in lizards, endoscopy is recommended.     

Correlation between cytologic and histopathologic diagnoses of bone lesions in dogs: a study of the diagnostic accuracy of bone cytology

Background: The diagnostic value of cytology compared with histopathology varies by tissue, but there is little information regarding this comparison involving canine bone. Objectives: The objective of this retrospective study was to compare primary pathologic processes for cytology and histopathology of canine bone lesions. We adopted a proposed standardized format for reporting studies of diagnostic accuracy. Methods: A computer search of canine medical records at the University of Minnesota Veterinary Medical Center from September 2002 through October 2006 identified 52 bone cytology samples that had incisional (IncB) and/or excisional (ExcB) biopsy performed. The primary pathologic process was determined by evaluation of original reports. Cytologic vs IncB and cytologic vs ExcB were compared pairwise for agreement. Agreement was compared for neoplastic and non-neoplastic processes using the combined IncB/ExcB data, which included all ExcB (n=21) and IncB when that was the only biopsy available (n=31). Combined data were used to determine the effect of cytology cellularity on the diagnostic correlation. Results: The correlation in primary process between cytology and IncB was 71%, and for ExcB was 71%. For lesions with a cytologic diagnosis of neoplasia compared with the combined IncB/ExcB data set, cytology and histopathology agreed in 92% of cases, which was significantly greater (P<.0001, chi(2)) than the 27% for non-neoplastic processes. Cytology cellularity significantly affected rates of correlation (P=.026), with high, moderate, and poor cellularity samples having concordant primary processes in 88%, 77%, and 47% of cases, respectively. Conclusions: Cytologic diagnosis of neoplasia for samples collected from canine bone correlates better with histopathology than cytologic diagnosis of non-neoplastic proliferative processes or inflammation. Cytologic diagnoses from highly cellular samples are more likely to correlate with histopathology than those from less cellular samples.     

Nasal and nasopharyngeal lymphoma in cats: 50 cases (1989-2005)

Lymphoma is the most common nasal cavity tumor in cats, yet few reports specifically address the anatomic, immunohistologic, and cytologic features of this neoplasm. Fifty cats were diagnosed with lymphoma at necropsy, via biopsy or by cytology alone. Ten cats displayed multiorgan involvement, and in 2 of these the involvement was limited to the cerebellum and frontal cortex, respectively. Of the tumors, 41 of 50 (82%) were classified as nasal lymphoma, 5 of 50 (10%) were classified as nasopharyngeal lymphoma, and 4 of 50 (8%) involved both nasal and nasopharyngeal tissue. Histologically, all were considered diffuse lymphoid neoplasms and no cats displayed features of follicular lymphoma. Of the 44 cases available for slide review by the pathologist, 40 of 44 (91%) were classified as immunoblastic lymphoma, 2 of 44 (5%) as diffuse large cell, and 1 as diffuse mixed; 1 was unclassified. Of the 45 cats for which immunohistochemical stains were available, 32 were uniformly positive for CD79a, 7 were uniformly CD3 positive, and 6 had a mixed population of CD79a and CD3 cells. Epithelioptropism was exhibited in 4 of 5 (80%) cats in which there was sufficient epithelium present for evaluation. Of those 4, 3 were B-cell and 1 was a granulated T-cell lymphoma. In the 21 cats which nasal cytology was performed, 15 were cytologically diagnosed with lymphoma; the diagnoses in the remaining five cats were inflammatory (n = 4), normal lymphoid tissue (n = 1), or nondiagnostic (n = 1). The most common biochemical abnormalities were panhyperproteinemia in 26/46 (57%) of cats and hypocholesterolemia in 11/46 (24%) of cats.     

Immunophenotyping lymphomas in dogs: a comparison of results from fine needle aspirate and needle biopsy samples

The reliability of utilizing cytologic samples for immunophenotyping canine lymphomas was evaluated by a systematic comparison of results from fine needle aspirate (FNA) to needle biopsy specimens stained by immunochemical methods. The specific reactivity of a selected panel of 12 antibodies to cell surface markers and intermediate filaments was assessed in 11 dogs by comparing cytologic to histologic samples. There was excellent correlation of results between immunostained cytologic and histologic samples. FNA sampling is a simple, noninvasive method for determining the lymphoid phenotype in canine lymphoma. In addition, this technique may be useful as a cytodiagnostic aid in differentiating lymphoid from non-lymphoid tumors and in assessing neoplastic vs. reactive or hyperplastic processes.     

Evaluation of the cytologic diagnosis of canine prostatic disorders

BACKGROUND: Canine prostatic disease is commonly investigated using cytologic techniques, especially now that ultrasound-guided fine needle cell aspiration (US-FNA) is widely available. Few studies, however, have evaluated the diagnostic accuracy of prostatic cytology. OBJECTIVE: The purpose of this study was to evaluate the usefulness of cytologic investigation of prostatic disease using US-FNA and other methods in comparison with histopathologic diagnosis. METHODS: Cytologic and histopathologic specimens of prostate or paraprostatic tissue from 25 adult dogs were retrospectively evaluated. Cytologic samples were obtained by US-FNA, prostatic massage, or direct impression smears or aspirates of tissue at surgery. Histopathologic sections were obtained from tissue collected by biopsy or at necropsy. RESULTS: Cytologic diagnoses were categorized as nondiagnostic (n = 2); cyst (n = 1); squamous metaplasia (n = 2); inflammation (n = 4); benign prostatic hyperplasia (BPH; n = 5); inflammation and BPH (n = 3); inflammation, BPH, and neoplasia (n = 1); inflammation and neoplasia (n = 3); and neoplasia (n = 4). Cytologic diagnoses agreed with final histologic diagnoses in 20 of the 25 cases (80%). Of those samples collected by US-FNA, 75% were concordant. Four samples obtained by US-FNA and 1 sample obtained by prostatic massage and wash had discordant results. CONCLUSIONS: The results of this study suggest strong agreement between cytologic and histopathologic diagnoses for prostatic conditions. Discordance in results obtained by US-FNA usually was the result of the pathologic process rather than a failure to obtain an appropriate sample.     

Diagnostic comparison of needle and wedge biopsy specimens of the liver in dogs and cats

OBJECTIVE: To compare morphologic diagnoses determined from needle biopsy specimens obtained from the livers of dogs and cats with morphologic diagnoses determined from wedge biopsy specimens. DESIGN: Prospective study. ANIMALS: 124 dogs and cats. PROCEDURE: 2 needle biopsy specimens were obtained from each animal; wedge biopsy specimens were obtained from the same liver lobe during laparotomy or postmortem examination. Histologic features were scored independently by 3 individuals; a morphologic diagnosis was rendered after histologic features were scored. Cases were included only if at least 2 of the 3 examiners agreed on the morphologic diagnosis; the definitive diagnosis was considered to be the morphologic diagnosis rendered for the wedge biopsy specimen. Physical characteristics (length, width, surface area, degree of fragmentation, and number of portal triads for needle biopsy specimens and surface area for wedge biopsy specimens) were determined. RESULTS: Definitive diagnoses included hepatic necrosis (n = 10), cholangitis-cholangiohepatitis (13), chronic hepatitis-cirrhosis (12), canine vacuolar hepatopathy (11), portosystemic vascular anomaly-microvascular dysplasia (17), neoplasia (10), miscellaneous hepatic disorders (18), and no hepatic disease (33). For individual examiners, the morphologic diagnosis assigned to needle biopsy specimens agreed with the morphologic diagnosis assigned to wedge biopsy specimens for 56 and 67% of the specimens. All 3 examiners agreed on the morphologic diagnosis assigned to needle and wedge biopsy specimens for 44 and 65% of the specimens, respectively. Morphologic diagnoses assigned to needle biopsy specimens concurred with the definitive diagnosis for 59 of 124 (48%) animals. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that needle biopsy specimens of the liver from dogs and cats must be interpreted with caution.