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.     

Paratracheal cervical mass in a dog

A 14-year-old female Welsh Terrier was presented for evaluation of multiple skin masses. Two of them were diagnosed as a follicular (epidermal) cyst and a sebaceous epithelioma by cytology and histopathology. The third mass was located in the subcutis adjacent to the cervical trachea. Clinical findings, thoracic radiography, and laboratory results were otherwise unremarkable. Cytologically, the cervical mass was characterized by the presence of round to polygonal cells with distinct cell borders, mild to moderate anisocytosis, round to oval eccentric nuclei with prominent nucleoli, and a variable amount of finely granular, eosinophilic cytoplasm. Differential diagnoses included endocrine/neuroendocrine tumors such as thyroid adenocarcinoma, medullary thyroid carcinoma, carotid body chemodectoma, and parathyroid carcinoma. The mass was removed surgically and submitted for histopathologic and immunohistochemical examination. Histologically, the mass was composed of rows and nests of densely packed cells separated by thin fibrovascular stroma. Neoplastic cells had moderate to large amounts of pale eosinophilic dusty or finely vacuolated cytoplasm and round to oval nuclei with finely dispersed chromatin and 1 or 2 small nucleoli. On immunohistochemistry, neoplastic cells were positive for chromogranin A, calcitonin, and neuron-specific enolase, and were negative for cytokeratin and thyroglobulin. The final diagnosis was medullary thyroid carcinoma, an uncommon endocrine tumor of dogs that has cytologic and histopathologic features similar to other endocrine and neuroendocrine tumors. Immunohistochemistry or immunocytochemistry should be performed to differentiate medullary thyroid carcinoma from other endocrine/neuroendocrine tumors of dogs.     

What is your diagnosis? Cervical mass in a cat

An 8-year-old female spayed domestic shorthair cat was presented for several months of weight loss, decreased appetite, and 2 bilateral, ventral cervical masses. Initial cytologic samples were interpreted as reactive lymphoid hyperplasia. Evaluation of subsequent mass aspirates revealed small numbers of large binucleated and multinucleated cells resembling Reed-Sternberg cells admixed with more numerous small and intermediate-sized lymphocytes. In histopathologic sections, the normal architecture of the lymph node was largely effaced by a slightly heterogeneous mass composed of round cells arranged in densely cellular sheets with a minor population of large (25-mum diameter) mononuclear cells and a few very large (30-40-mum diameter) binucleated or multinucleated cells interpreted as Reed-Sternberg-like cells. Immunohistochemically, the large neoplastic (Reed-Sternberg-like) cells were negative for CD18, CD3, CD20, and CD79a while the background population consisted of about 70% T cells and 30% B cells. This pattern of immunohistochemical staining along with cytologic and histopathologic findings supported a diagnosis of Hodgkin's-like lymphoma, specifically, the lymphocyte-rich subtype. Hodgkin's-like lymphoma has been reported previously in cats and should be suspected when Reed-Sternberg-like cells are observed in cytologic preparations of lymph node aspirates. Histopathology and immunohistochemistry are necessary for a definitive diagnosis.     

Association between liver copper concentration and subclinical hepatitis in Doberman Pinschers

The prevalence of subclinical hepatitis was investigated in a group of 106 randomly selected 3-year-old Doberman Pinschers. Histopathologic examination of liver samples from 65 dogs (52 dogs with high bile acids, alkaline phosphatase activity, or alanine aminotransferase activity or with copper granules in hepatocytes in a liver aspirate and 13 normal dogs) revealed subclinical hepatitis in 22 dogs (19 females and 3 males). Liver copper concentrations measured by instrumental neutron activation analysis was significantly higher (mean +/- SD; 419 +/- 414 microg/g dry matter) in dogs with hepatitis than those without liver disease (197 +/- 113 microg/g; P = .0008). At 2.6 +/- 0.6 years hepatitis persisted in 5 of 16 dogs available for examination. One dog with a high copper concentration but normal liver subsequently developed subclinical hepatitis after 3 years. During the follow-up period, the average copper concentration of the 6 dogs with persistent subclinical hepatitis was 939 +/- 299 microg/g and had continued to rise significantly (P = .02). The hepatitis in these dogs was associated with apoptotic hepatocytes and copper-laden Kupffer cells in centrolobular regions. The results of this study suggest that there is a relationship among copper storage, hepatocellular damage, and hepatitis in Doberman Pinschers.     

Characterization of portal lymphocytic infiltrates in feline liver

To better understand the relationship of portal lymphocytic infiltrates to feline inflammatory liver disease, liver sections were semiquantitatively evaluated from healthy cat and liver sections randomly selected at necropsy from clinical cases. Healthy specific pathogen-free kittens and healthy young adult cats had up to 10 lymphocytes and plasma cells per portal area. Neutrophils were infrequently seen in portal areas. Approximately one-third of sections obtained from clinical cases younger than 10 years had increased numbers of lymphocytes and plasma cells in portal areas. Seventy percent of these had a concurrent increase in neutrophils. Eighty-two percent of liver sections obtained from clinical cases older than 10 years had increased numbers of portal lymphocytes and plasma cells. Almost all of these sections had concurrent fibrosis and bile duct proliferation. These data indicate that a progressive lymphocytic portal hepatitis is a common finding in cats older than 10 years.     

Characterization of the inflammatory infiltrate in canine chronic hepatitis.

Canine chronic hepatitis (CCH) is a progressive inflammatory disease of unknown etiology. To characterize the inflammatory infiltrate, 16 dogs with CCH were selected and classified into three groups based on the stage of fibrosis, as evaluated with Masson's trichrome stain. The inflammatory infiltrate in each liver section was immunohistochemically characterized and evaluated using CD3, lysozyme, lamba and kappa light chain, and alpha-smooth muscle actin antibodies. Numerous breeds were affected, and middle-aged females predominated in this select group. Necroinflammatory activity progressively increased and then waned as the hepatitis progressed to cirrhosis. CD3+ lymphocytes were the most numerous lymphoid cells in dogs with CCH. Degenerate hepatocytes were occasionally surrounded by CD3+ lymphocytes. Necrosis was positively correlated with the number of CD3+ lymphocytes. The lamba and kappa light chain-positive cell infiltrate was variable but generally mild. A positive correlation between the lambda and kappa light chain-positive cells and the portal alpha-smooth muscle actin was found. The number of alpha-smooth muscle actin-positive cells (myofibroblasts) in portal triads and fibrous septa was positively correlated with the stage of fibrosis. In contrast, no correlation was found between the number of lysozyme-positive cells (Kupffer cells) and the stage of fibrosis. These results further support the idea of an immune-mediated process in CCH and suggest that periductular myofibroblasts play an important role in canine liver fibrogenesis.     

Improvement in liver pathology after 4 months of D-penicillamine in 5 doberman pinschers with subclinical hepatitis

Five female Doberman Pinschers with increased hepatic copper concentrations and persistent (3-4 years) subclinical hepatitis were treated with D-penicillamine for 4 months. Before and after treatment, the dogs underwent clinical, hematologic (red blood cell, white blood cell, and differential and thrombocyte counts), and clinical chemistry (creatinine, alkaline phosphatase, alanine aminotransferase, and total bile acid concentrations) examinations, and liver biopsies were examined histologically and their copper content measured quantitatively. No adverse effects were observed during treatment, and CBC and serum chemistry test results did not change. The mean liver copper concentration was 1,036 mg/kg dry matter before treatment and decreased to 407 mg/kg after treatment (P = .03). The copper concentrations had decreased (by between 134 and 1,135 mg/kg dry matter) in all of the dogs. The histopathologic appearance had improved or returned to normal in all 5 dogs. We conclude that D-penicillamine effectively reduced copper retention in these dogs and improved the histopathologic appearance of the lesions. However, because D-penicillamine has both copper-chelating and anti-inflammatory properties, it is not possible to draw conclusions on the etiology of this disease.     

Upregulation of major histocompatibility complex class II antigens in hepatocytes in Doberman hepatitis

Major histocompatibility complex (MHC) class II antigen expression in hepatocytes and its correlation with mononuclear cell infiltration into the liver were studied using immunohistochemical techniques in 38 Dobermans with Doberman hepatitis (DH). Liver biopsy samples were obtained from 18 dogs at the subclinical stage. Autopsy samples were taken from 6 DH dogs euthanized for a reason other than DH, from 14 dogs euthanized because of advanced liver failure and from 6 control Dobermans. Upon examination of the control liver samples, no expression of MHC class II antigens was detected in hepatocytes. By contrast, in 15 of the 18 DH biopsies (83%) and in all 20 DH autopsy liver samples, hepatocytes expressed MHC class II molecules. MHC class II expression was either cytoplasmic or membranous and occurred in conjunction with lymphocyte infiltration. A correlation between the inflammatory reaction and the expression of MHC class II in hepatocytes suggests that the aberrant expression of MHC class II in hepatocytes is induced by cytokines. Hepatocytes presenting a putative MHC class II molecule-associated autoantigen could thus become the target of an immune attack mediated by CD4+ T cells. In addition, corticosteroid treatment was observed to significantly decrease MHC class II expression in DH hepatocytes. Inappropriate MHC class II expression in hepatocytes and mononuclear cell infiltration are suggesting an autoimmune nature for chronic hepatitis in Dobermans.     

Cytologic evaluation of benign and malignant hemophagocytic disorders in canine bone marrow

Abstract: Canine hemophagocytic disorders were studied to better understand the cytologic features that differentiate benign and malignant disease. Of 286 canine clinical bone marrow reports evaluated retrospectively, 13 (4.5%) noted at least 3% hemophagocytic macrophages. Macrophages comprised between 6% and 44% of nucleated bone marrow cells. Clinical diagnoses for dogs with hemophagocytic disorders included malignant histiocytosis (n = 2), myelodysplastic syndromes (n = 4), round cell neoplasia (n = 2), immune-mediated disorders (n = 2), and idiopathic hemophagocytic syndrome (n = 3). Differentiation of benign and malignant forms of histiocytosis was problematic. Two dogs with a diagnosis of hemophagocytic syndrome had macrophages with atypical features similar to those described for malignant histiocytosis. Furthermore, only 2 of 11 dogs with presumably benign hemophagocytic disorders had exclusively mature macrophages in bone marrow. Other dogs had variable numbers of large reticular-type cells characterized by lacy chromatin, anisocytosis, anisokaryosis, and prominent and/or multiple nucleoli. On the basis of these results, cytomorphologic evaluation of bone marrow alone may not be adequate to consistently differentiate benign and malignant forms of hemophagocytic disorders.     

The influence of age on the cytology of the liver in healthy dogs

Liver cytology was evaluated in 28 healthy dogs 1-14 years of age with normal liver structure and function. Smears were stained with May-Grünwald-Giemsa. Hepatocytes had distinct cell borders, and cells did not overlap. Cells with two nuclei and cells with intranuclear crystalloid structures were observed regularly. Cytoplasm contained small numbers of vacuoles characteristic of glycogen and lipid and small amounts of pigment consistent with ceroid or bile. Nuclei were uniform. Small numbers of biliary epithelial cells were seen in most samples. Lymphocytes and neutrophils occurred in small numbers, with lipocytes, mast cells, fibrocytes, mesothelial cells, eosinophils, and Kupffer macrophages seen less frequently. Mean parenchymal cell sizes were significantly greater in older dogs, but no age-related differences were observed in nuclear size. Older dogs also had a significantly increased number of nuclei per cell. There were more neutrophils in young and old dogs than in middle-aged dogs.     

Inherited, chronic, progressive hepatic degeneration in Bedlington terriers with increased liver copper concentrations: clinical and pathologic observations and comparison with other copper-associated liver diseases

One hundred nineteen hepatic tissue samples from 117 Bedlington Terriers were divided into 6 groups depending on the severity of histopathologic hepatic changes. Group 0 comprised dogs with microscopically normal livers. Group I dogs had copper-positive, lipofuscin-containing lysosomes present in centrilobular hepatocytes. Microfoci of hepatic necrosis, in addition to the increased numbers of the copper-positive, lipofuscin-containing lysosomes in centrilobular and periportal hepatocytes, were present in group II dogs. Group III dogs had more copper-positive, lipofuscin-containing lysosomes present translobularly and morphologic changes consistent with chronic active hepatitis. Mixed micro- or macronodular cirrhosis and translobular presence of copper-positive, lipofuscin-containing lysosomes characterized group IV dogs. Dogs in group V had massive hepatic necrosis and morphologic changes that were consistent with the changes in group III and IV dogs. Histochemical staining for copper was useful in making the microscopic diagnosis of this disease and was shown to be necessary in early diagnosis (group I) when other clinical and pathologic values associated with this syndrome were not consistently abnormal. Copper histochemical stains varied in sensitivity. Timm's silver sulfide was more sensitive for copper than was rubeanic acid, which was more sensitive than rhodanine staining. The brown pigment associated with the copper in the lysosomes was shown to be lipofuscin pigment with the aid of histochemical staining with orcein, Prussian blue, periodic acid-Schiff, and acid-fast stains together with fluorescent microscopy (excitation maxima: 365 nm; emissions: 420 + nm). Since these were positive only in later stages of the hepatic disease, they were not especially useful in its early diagnosis. The severity of the histopathologic hepatic changes was shown to increase with age and was associated with increasing hepatic copper concentration. These observations illustrate that this inherited, chronic hepatic degeneration in the Bedlington Terrier is progressive. Clinical chemical tests were diagnostically useful only in later stages of the disease. Alanine transaminase activity was of most value, but was not always abnormal, even when severe hepatic damage was present. Clinical signs of hepatic disease were seen in dogs in groups III, IV, and V. Death due to hepatic failure occurred only in dogs in groups III, IV, and V. Hemosiderin was present in increased amounts in the liver, bone marrow, spleen, and lymph nodes of affected Bedlington Terriers, indicating that a possible defect in iron metabolism and/or an increase in RBC turnover existed.(ABSTRACT TRUNCATED AT 400 WORDS)     

Coelomic mass in a rock dove (Columba livia)

A 15-year-old domestic rock dove (Columbia livia) was presented to the Service de Médecine Zoologique of the Université de Montréal with a 10-day history of lethargy and chronic weight loss of 1-year duration. Ultrasonographic evaluation of the coelomic cavity revealed the presence of effusion and a well-defined mass containing variably sized hypoechoic nodules of unknown origin. Cytologic evaluation of fine-needle aspirates of the mass indicated a malignant epithelial tumor consisting of round cells arranged individually and in clusters, with large nuclei, prominent nucleoli, moderate anisocytosis and anisokaryosis, atypical mitoses, occasional binucleation and multinucleation, and large numbers of ruptured cells. A diagnosis of seminoma was established on histologic sections obtained at necropsy. The cytologic features of this tumor were similar to those of canine seminomas except for the presence of lymphocytes, which were not observed in significant numbers in cytologic smears or histologic sections. Seminoma should be included in the differential diagnosis for a space-occupying mass causing organ displacement within the coelomic cavity of a male bird.     

CORRELATION OF ULTRASOUND FINDINGS,LIVER AND SPLEEN CYTOLOGY,AND PROGNOSIS IN THE CLINICAL STAGING OF HIGH METASTATIC RISK CANINE MAST CELL TUMORS

Cytologic sampling of the ultrasonographically normal spleen and liver is not implemented routinely in the clinical staging of canine cutaneous mast cell tumors and normal ultrasound findings are often accepted as sufficient evidence for ruling out splenic or liver metastasis. Our objective was to define the specificity and sensitivity of ultrasound findings for diagnosis of mast cell infiltration when verified with cytologic evaluation, and to define the prognostic role of cytologic evaluation of liver and splenic aspirates. Dogs with a diagnosis of clinically aggressive grade II, or grade III mast cell tumor treated with a combination vinblastine/CCNU chemotherapy protocol, were selected retrospectively based on availability of cytologic evaluation of spleen plus or minus liver for staging. Out of 19 dogs, 10 dogs had a grade II tumor and nine a grade III tumor. Seven dogs had mast cell infiltration of the spleen, liver, or both. The sensitivity of ultrasound for detecting mast cell infiltration was 43% for the spleen and 0% for the liver. Dogs with positive cytologic evidence of mast cell infiltration to spleen, liver, or both had significantly shorter survival (100 vs. 291 days) than dogs without evidence of mast cell infiltration (P<0.0001). Routine splenic aspiration should be performed regardless of ultrasonographic appearance in dogs with a clinically aggressive mast cell tumor.     

Fine needle aspiration cytology of pilomatricoma in three dogs

Background — Fine needle aspiration cytology is being used for the diagnosis of various neoplasms, but we are unaware of reports dealing with the cytologic features of canine pilomatricoma.
Objective — The purpose of this report was to describe the cytologic features of pilomatricoma in 3 dogs.
Methods — Fine-needle aspirates were obtained from cutaneous masses using a 25-ga needle. Smears were prepared and stained with May-Grünwald-Giemsa and hematoxylin and eosin. The cutaneous masses were excised and routinely processed for histologic examination.
Results — Cytologic features of all 3 tumors included high cellularity and numerous clusters of tightly arranged of basaloid cells with evenly distributed chromatin and small distinct nucleoli surrounding sheets of "ghost cells". Ghost cells were characterized by a central unstained zone corresponding to the site previously occupied by the nucleus. Amorphous keratinized material was observed in 1 tumor. Histopathologic findings confirmed the diagnosis of pilomatricoma in all 3 cases.
Conclusions — Basaloid cells in association with ghost cells are important cytopathologic criteria that may provide a definitive cytologic diagnosis of pilomatricoma in dogs, and may help avoid a false diagnosis of malignancy.     

Correlation of cytologic and histopathologic findings with perinodal echogenicity of abdominal lymph nodes in dogs and cats

Abdominal lymphadenopathy in dogs and cats is routinely investigated with ultrasound. As the determination between benign and neoplastic etiologies of lymphadenopathy affects patient management, specific sonographic characteristics associated with both benign and neoplastic lymph nodes have been suggested. However, a significant overlap between these characteristics exists, necessitating a cytologic or histopathologic diagnosis in most instances. The objectives of this retrospective, cross‐sectional study were to evaluate whether echogenicity of perinodal fat could be a discriminator between benign and neoplastic abdominal lymphadenopathy and to assess if additional sonographic features associated with malignancy could be identified in lymph nodes with hyperechoic perinodal fat. Small animal patients (257 dogs and 117 cats) with sonographic evidence of abdominal lymphadenopathy and a cytological or histopathological diagnosis were evaluated for differences in the proportions of sonographic features between benign and neoplastic groups. Greater maximum long axis diameter (in dogs and cats) and a greater number of abnormal lymph nodes (in cats) were associated with malignancy in lymph nodes with hyperechoic perinodal fat. Canine lymph nodes with round cell neoplasia were significantly more likely to have hyperechoic perinodal fat. Lymph nodes affected with other neoplasia or with lymphadenitis were equally likely to have normal or hyperechoic perinodal fat. Reactive lymph nodes were significantly less likely to have hyperechoic perinodal fat in both species. These results suggest that though echogenicity of perinodal fat is a nonspecific finding, abdominal lymph nodes with hyperechoic perinodal fat are less likely to be reactive and sampling of these lymph nodes may be indicated.     

Hepatotoxicity associated with CCNU (lomustine) chemotherapy in dogs

One hundred seventy-nine tumor-bearing dogs were treated with 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) between 1995 and 2001. CCNU was given as a single dose of 50-110 mg/m2 body surface area PO. Treatment interval varied, but the minimal interval between CCNU doses was 3 weeks. After treatment, 11 dogs (6.1%) developed hepatic toxicity. The median number of CCNU doses and the median total cumulative CCNU dose were significantly higher in dogs that developed hepatic toxicity (4 doses; 350 mg/m2) than in dogs without hepatic damage (3 doses; 230 mg/m2). Median duration to detection of hepatic toxicity from the last dose of CCNU was 11 weeks (range 2-49 weeks). Common biochemical abnormalities were abnormally high serum liver enzyme activities and hypoalbuminemia. Six dogs with CCNU-associated hepatic toxicity had ascites, and 3 dogs had concurrent pleural effusion. Serum concentrations of bile acids were abnormally high in 4 of 5 dogs tested. Percutaneous ultrasound-guided liver biopsies were performed in 10 dogs, and findings were nonspecific and chronic in nature. Seven dogs were euthanized because of progressive liver failure, and their median survival from diagnosis of liver disease was 9 weeks. Three dogs died of other causes and 1 dog of unknown cause. Although clinical signs resolved in 3 dogs, biochemical abnormalities and histopathologic lesions persisted 4 to 38 months from the time of diagnosis of liver disease. Our findings suggest that CCNU can cause delayed, cumulative dose-related, chronic hepatotoxicity that is irreversible and can be fatal.     

Thyroid follicular adenocarcinoma in a ferret

A 5-year-old male castrated ferret was presented to the Washington State University College of Veterinary Medicine for evaluation of progressive hair loss and a large, rapidly growing ventral neck mass. The patient had been diagnosed previously with an insulinoma, which was managed medically. Fine-needle aspirates of the neck mass were performed. The cytologic results were most consistent with epithelial neoplasia, likely a carcinoma; thyroid origin was considered likely based on tumor location and cell morphology. The tumor grew rapidly, and the owners elected euthanasia 1 week after examination. At necropsy, a circumscribed, ovoid mass disrupted the right cervical musculature next to the right lobe of the thyroid gland. Histopathologic evaluation revealed an infiltrative mass consisting of cuboidal cells arranged in solid sheets and irregular follicles enclosing colloid. The cells were large, with prominent nucleoli, and had a high mitotic rate. The histopathologic diagnosis was consistent with thyroid follicular adenocarcinoma. Immunochemical findings confirmed thyroglobulin production by neoplastic cells, but to a lesser extent than in normal ferret thyroid tissue. To our knowledge, this is the first case of thyroid follicular adenocarcinoma to be reported in a ferret, with only 1 other case of thyroid carcinoma, a C-cell carcinoma, described previously.     

Three cases of canine bile peritonitis with mucinous material in abdominal fluid as the prominent cytologic finding

Background: Bile peritonitis is a severe, nonseptic inflammatory response to bile in the peritoneal cavity. It may result from generalized or localized leakage of bile due to spontaneous rupture of the biliary system or as a complication of biliary tract inflammation, obstruction, manipulation, or trauma. Cytologically, bile in abdominal fluid appears as golden-green granular pigment.
Objective: The purpose of this report is to describe the atypical cytologic features of abdominal fluid in 3 dogs with bile peritonitis.
Methods: As part of a diagnostic workup, abdominal fluid was obtained from 3 dogs with bile peritonitis and analyzed. In 2 dogs, fluid bilirubin concentration was determined and Hall's bile stain, Alcian blue-periodic acid-Schiff stain, and Mayer's mucicarmine stain were applied to direct smears of the fluid.
Results: Acellular mucinous fibrillar material in clumps and lakes was the prominent cytologic finding in the abdominal fluid from all 3 dogs. Bile pigment was not observed. Fluid from the 3 dogs contained increased numbers of inflammatory cells, predominantly neutrophils. Total protein concentration ranged from 2.9 to 5.6 g/dL. Fluid total bilirubin concentration was greater than twice that of the concurrent serum bilirubin concentration. Based on results of the special stains, the amorphous material was positive for mucosubstances, but was negative for bilirubin. In all dogs, bile peritonitis originated from a rent in the common bile duct.
Conclusions: Bile peritonitis with fibrillar mucinous material in abdominal fluid has not been described previously in dogs. The material was similar to "white bile" observed in humans and experimentally in dogs as a sequela to extrahepatic biliary tract obstruction. When mucinous material is observed in abdominal fluid from dogs and the fluid bilirubin concentration is greater than twice the serum bilirubin concentration, rupture of the extrahepatic biliary tract should be suspected.     

Clinical,cytologic, and histologic features of a mammary micropapillary carcinoma in a dog

Mammary invasive micropapillary carcinoma is a rare variant of mammary carcinoma that was recently recognized in dogs. The cytologic features and biologic behavior of such neoplasms in dogs have not yet been widely discussed in the veterinary literature. We report the clinical, cytologic, and histologic features of a canine micropapillary carcinoma in a 13‐year‐old female mongrel dog. The mammary region presented with extreme local pain, severe edema and erythema, and multifocal epidermal ulceration, which is typical for an inflammatory mammary carcinoma. Fine‐needle aspirates were highly cellular and consisted of individual cells and papillary cell clusters with characteristics of malignant epithelial cells. Histologic examination revealed neoplastic cells arranged in small papillae without fibrovascular cores, sometimes inside clear lymphatic spaces, indicating lymphovascular invasion. Regional lymph node evaluation revealed metastatic cells. Due to deteriorating clinical condition the dog was euthanatized 5 months after mastectomy. At necropsy, metastatic neoplastic mammary cells were found in popliteal and mediastinal lymph nodes, the right femoral biceps muscle, liver, heart, lungs, and urinary bladder.     

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.