Feline minor salivary gland adenocarcinoma: retrospective case series and literature review.

CASE SERIES SUMMARY: Salivary gland adenocarcinoma, of major or minor salivary gland origin, is an uncommon tumor in cats. This article describes the clinical features, morbidity and survival rates of four cats with salivary gland adenocarcinoma arising from minor salivary gland tissue. Medical records from a private multicenter dentistry and oral surgery practice were reviewed for the period between 2007 and 2021. Four cats were included in this retrospective case series study, with oral masses on either the right or left caudal mandibular labial buccal mucosa. The inclusion criteria included a diagnosis of salivary gland adenocarcinoma in an anatomical location with lack of involvement of a major salivary gland, complete medical history and a follow-up of at least 6 months. The age range of the cats was 9-15 years; three of the cats were castrated males and one was a spayed female. Curative intent surgery was performed in three cats, whereas palliative surgery (debulking) owing to extensive soft tissue invasion was performed in one cat. Survival times were in the range of 210-1730 (mean 787) days. All four cats were euthanized owing to local recurrence and decreased quality of life, regardless of treatment modality. RELEVANCE AND NOVEL INFORMATION: There are limited documented studies reporting the prevalence of salivary gland neoplasia affecting minor disseminated glands in the oral cavity of feline patients. Salivary gland adenocarcinoma should be a differential in cats presenting with caudal labial masses. Surgical resection has been the recommended treatment for salivary gland neoplasia of major salivary gland origin. According to this current case series, we propose that early aggressive surgical treatment with wide surgical margins should be performed for cats with salivary gland adenocarcinoma of minor salivary gland origin. Surgery increased the quality and duration of life; however, each patient was euthanized owing to local recurrence and morbidity.

Correlation Between Radiographic and Histopathologic Findings Associated with Unerupted Teeth in Dogs.

An association between unerupted teeth and dentigerous cysts is well known,1- 4 however little is known about the presence of disease and histopathologic changes in unerupted teeth without radiographic evidence of cyst formation. Forty-two dogs representing 25 breeds, ranging in age from 5 months to 12 years were selected based on radiographic evidence of an unerupted tooth or teeth, either as a primary complaint or incidental finding. Dogs meeting the study criteria were presented to a private dental referral practice within a period of eighteen months from December 2016 through May 2018. Patients were treated with conservative en bloc resection of the unerupted tooth and overlying bone as well as debridement of any cystic structure and biopsy of the samples collected. Radiographs were evaluated using criteria previously established to assess for evidence of a cyst.1, 5- 7 A total of 68 unerupted teeth were identified; 63 (92.7%) were mandibular first premolar teeth. Of the 63 unerupted mandibular first premolar teeth, 28 (44.4%) had radiographic evidence of a cystic structure. Histopathology revealed that 21 of 28 (75.0%) had evidence of non-keratinizing stratified squamous epithelium consistent with a cyst lining. Of the remaining 35 of 63 (55.6%) mandibular first premolar teeth with no radiographic evidence of a cyst, 27 (77.1%) had no histologic evidence of epithelium associated with the impacted tooth. Notably however, the remaining 8 of 35 (22.9%) unerupted teeth without radiographic evidence of a cyst did have histologic evidence of non-keratinizing stratified squamous epithelium associated with the impacted tooth.

Meningeal B Cell Clusters Correlate with Submeningeal Pathology in a Natural Model of Multiple Sclerosis.

Multiple sclerosis (MS) is an idiopathic demyelinating disease in which meningeal inflammation correlates with accelerated disease progression. The study of meningeal inflammation in MS has been limited because of constrained access to MS brain/spinal cord specimens and the lack of experimental models recapitulating progressive MS. Unlike induced models, a spontaneously occurring model would offer a unique opportunity to understand MS immunopathogenesis and provide a compelling framework for translational research. We propose granulomatous meningoencephalomyelitis (GME) as a natural model to study neuropathological aspects of MS. GME is an idiopathic, progressive neuroinflammatory disease of young dogs with a female bias. In the GME cases examined in this study, the meninges displayed focal and disseminated leptomeningeal enhancement on magnetic resonance imaging, which correlated with heavy leptomeningeal lymphocytic infiltration. These leptomeningeal infiltrates resembled tertiary lymphoid organs containing large B cell clusters that included few proliferating Ki67+ cells, plasma cells, follicular dendritic/reticular cells, and germinal center B cell-like cells. These B cell collections were confined in a specialized network of collagen fibers associated with the expression of the lympho-organogenic chemokines CXCL13 and CCL21. Although neuroparenchymal perivascular infiltrates contained B cells, they lacked the immune signature of aggregates in the meningeal compartment. Finally, meningeal B cell accumulation correlated significantly with cortical demyelination reflecting neuropathological similarities to MS. Hence, during chronic neuroinflammation, the meningeal microenvironment sustains B cell accumulation that is accompanied by underlying neuroparenchymal injury, indicating GME as a novel, naturally occurring model to study compartmentalized neuroinflammation and the associated pathology thought to contribute to progressive MS.

Malakoplakia in the Urinary Bladder of 4 Puppies.

Malakoplakia in humans most often affects the urinary bladder and is characterized by inflammation with von Hansemann-type macrophages, with or without Michaelis-Gutmann bodies, and is frequently associated with Escherichia coli infection. We describe the microscopic features of malakoplakia in the urinary bladder of 4 puppies. In all cases, the lamina propria of the urinary bladder was markedly expanded by sheets of large, round to polygonal macrophages with intracytoplasmic, periodic acid-Schiff-positive granules and granular inclusions, and rare Prussian blue-positive inclusions. Macrophages were positive for CD18 and Iba1. In 2 cases, Michaelis-Gutmann bodies were detected with hematoxylin and eosin stain and were best demonstrated with von Kossa stain. E. coli infection was confirmed in 2 cases with bacterial culture or polymerase chain reaction (PCR) and sequencing of the bacterial 16S ribosomal RNA gene. Transmission electron microscopy of one case demonstrated macrophages with abundant lysosomes, phagolysosomes, and rod-shaped bacteria. Microscopic features were similar to human cases of malakoplakia. In dogs, the light microscopic characteristics of malakoplakia closely resemble granular cell tumors and histiocytic ulcerative colitis.

Clinical, histopathologic, and immunohistochemical features of 13 cases of canine gallbladder neuroendocrine carcinoma.

In this retrospective descriptive study, we characterized the clinical, histologic, and immunohistochemical features of 13 cases of canine gallbladder neuroendocrine carcinoma (GB-NEC). Immunohistochemical stains for neuroendocrine (neuron-specific enolase [NSE], chromogranin A, synaptophysin) and gastrin markers were evaluated, and clinicopathologic and follow-up data were obtained for all cases. The average age at diagnosis was 8.9 y, and breeds included 6 Boston Terriers, 2 Bichon Frise, 1 Poodle, 1 English Bulldog, 1 French Bulldog, and 2 mixed-breed dogs. Boston Terriers were overrepresented in this cohort, and therefore a breed predilection is possible. Most dogs were presented with emesis and elevated liver enzyme activities: 13 of 13 had elevated alanine aminotransferase and alkaline phosphatase activities; 8 of 13 had elevated aspartate aminotransferase activity; 7 of 13 had elevated gamma-glutamyl transferase activity. Abdominal ultrasound and/or exploratory surgery revealed a gallbladder mass. All neoplasms had similar histologic features and positive immunoreactivity for NSE, chromogranin A, synaptophysin, and gastrin. Vascular invasion was noted in 8 of 13 neoplasms, and metastasis was present in 6 of 13 cases (4 hepatic and 2 pulmonary metastases). The median survival time was 3.7 y in patients who died; 5 of 8 deaths were directly attributed to the GB-NEC, 3 of which had metastatic spread. GB-NECs have the potential to metastasize; however, surgical excision may be curative in a subset of dogs.

Agreement in Histological Assessment of Mitotic Activity Between Microscopy and Digital Whole Slide Images Informs Conversion for Clinical Diagnosis.

Validating digital pathology as substitute for conventional microscopy in diagnosis remains a priority to assure effectiveness. Intermodality concordance studies typically focus on achieving the same diagnosis by digital display of whole slide images and conventional microscopy. Assessment of discrete histological features in whole slide images, such as mitotic figures, has not been thoroughly evaluated in diagnostic practice. To further gauge the interchangeability of conventional microscopy with digital display for primary diagnosis, 12 pathologists examined 113 canine naturally occurring mucosal melanomas exhibiting a wide range of mitotic activity. Design reflected diverse diagnostic settings and investigated independent location, interpretation, and enumeration of mitotic figures. Intermodality agreement was assessed employing conventional microscopy (CM40×), and whole slide image specimens scanned at 20× (WSI20×) and at 40× (WSI40×) objective magnifications. An aggregate 1647 mitotic figure count observations were available from conventional microscopy and whole slide images for comparison. The intraobserver concordance rate of paired observations was 0.785 to 0.801; interobserver rate was 0.784 to 0.794. Correlation coefficients between the 2 digital modes, and as compared to conventional microscopy, were similar and suggest noninferiority among modalities, including whole slide image acquired at lower 20× resolution. As mitotic figure counts serve for prognostic grading of several tumor types, including melanoma, 6 of 8 pathologists retrospectively predicted survival prognosis using whole slide images, compared to 9 of 10 by conventional microscopy, a first evaluation of whole slide image for mitotic figure prognostic grading. This study demonstrated agreement of replicate reads obtained across conventional microscopy and whole slide images. Hence, quantifying mitotic figures served as surrogate histological feature with which to further credential the interchangeability of whole slide images for primary diagnosis.

Plasma and tissue angiotensin-converting enzyme 2 activity and plasma equilibrium concentrations of angiotensin peptides in dogs with heart disease.

BACKGROUND: Angiotensin-converting enzyme 2 (ACE2) is a homologue of angiotensin-converting enzyme (ACE) and produces angiotensin peptides (APs), such as angiotensin 1-9 and 1-7 that are vasodilatory and natriuretic, and act to counterbalance angiotensin II. HYPOTHESIS: Evidence of ACE2 can be found in tissues and plasma of dogs. Equilibrium concentrations of renin angiotensin aldosterone system (RAAS) APs differ in dogs with heart disease compared to healthy dogs and recombinant human ACE2 (rhACE2) alters relative concentrations of APs. ANIMALS: Forty-nine dogs with and 34 dogs without heart disease. METHODS: Immunohistochemistry and assays for tissue and plasma ACE2 activity and equilibrium concentrations of plasma RAAS APs were performed. RESULTS: Immunolabeling for ACE2 was present in kidney and myocardial tissue. Median plasma ACE2 activity was significantly increased in dogs with congestive heart failure (CHF; 6.9 mU/mg; interquartile range [IQR], 5.1-12.1) as compared to control (2.2 mU/mg; IQR, 1.8-3.0; P = .0003). Plasma equilibrium analysis of RAAS APs identified significant increases in the median concentrations of beneficial APs, such as angiotensin 1-7, in dogs with CHF (486.7 pg/mL; IQR, 214.2-1168) as compared to those with preclinical disease (41.0 pg/mL; IQR, 27.4-45.1; P < .0001) or control (11.4 pg/mL; IQR, 7.1-25.3; P = .01). Incubation of plasma samples from dogs with CHF with rhACE2 increased beneficial APs, such as angiotensin 1-9 (preincubation, 10.3 pg/mL; IQR, 4.4-37.2; postincubation, 2431 pg/mL; IQR, 1355-3037; P = .02), while simultaneously decreasing maladaptive APs, such as angiotensin II (preincubation, 53.4 pg/mL; IQR, 28.6-226.4; postincubation, 2.4 pg/mL; IQR, 0.50-5.8; P = .02). CONCLUSIONS AND CLINICAL IMPORTANCE: Recognition of the ACE2 system expands the conventional view of the RAAS in the dog and represents an important potential therapeutic target.

Automated Computational Detection, Quantitation, and Mapping of Mitosis in Whole-Slide Images for Clinically Actionable Surgical Pathology Decision Support.

BACKGROUND: Determining mitotic index by counting mitotic figures (MFs) microscopically from tumor areas with most abundant MF (hotspots [HS]) produces a prognostically useful tumor grading biomarker. However, interobserver concordance identifying MF and HS can be poorly reproducible. Immunolabeling MF, coupled with computer-automated counting by image analysis, can improve reproducibility. A computational system for obtaining MF values across digitized whole-slide images (WSIs) was sought that would minimize impact of artifacts, generate values clinically relatable to counting ten high-power microscopic fields of view typical in conventional microscopy, and that would reproducibly map HS topography. MATERIALS AND METHODS: Relatively low-resolution WSI scans (0.50 µm/pixel) were imported in grid-tile format for feature-based MF segmentation, from naturally occurring canine melanomas providing a wide range of proliferative activity. MF feature extraction conformed to anti-phospho-histone H3-immunolabeled mitotic (M) phase cells. Computer vision image processing was established to subtract key artifacts, obtain MF counts, and employ rotationally invariant feature extraction to map MF topography. RESULTS: The automated topometric HS (TMHS) algorithm identified mitotic HS and mapped select tissue tiles with greatest MF counts back onto WSI thumbnail images to plot HS topographically. Influence of dye, pigment, and extraneous structure artifacts was minimized. TMHS diagnostic decision support included image overlay graphics of HS topography, as well as a spreadsheet and plot of tile-based MF count values. TMHS performance was validated examining both mitotic HS counting and mapping functions. Significantly correlated TMHS MF mapping and metrics were demonstrated using repeat analysis with WSI in different orientation (R 2 = 0.9916) and by agreement with a pathologist (R 2 = 0.8605) as well as through assessment of counting function using an independently tuned object counting algorithm (OCA) (R 2 = 0.9482). Limits of agreement analysis support method interchangeability. MF counts obtained led to accurate patient survival prediction in all (n = 30) except one case. By contrast, more variable performance was documented when several pathologists examined similar cases using microscopy (pair-wise correlations, rho range = 0.7597-0.9286). CONCLUSIONS: Automated TMHS MF segmentation and feature engineering performance were interchangeable with both observer and OCA in digital mode. Moreover, enhanced HS location accuracy and superior method reproducibility were achieved using the automated TMHS algorithm compared to the current practice employing clinical microscopy.

Surgical management of maxillary and premaxillary osteomyelitis in a reticulated python (Python reticulatus).

CASE DESCRIPTION A 1-year-old reticulated python (Python reticulatus) was evaluated because of a 2-week history of wheezing and hissing. CLINICAL FINDINGS Rostral facial cellulitis and deep gingival pockets associated with missing rostral maxillary teeth were evident. Tissues of the nares were swollen, resulting in an audible wheeze during respiration. Multiple scars and superficial facial wounds attributed to biting by live prey were apparent. Radiographic examination revealed bilateral, focal, rostral maxillary osteomyelitis. TREATMENT AND OUTCOME Wound irrigation, antimicrobials, and anti-inflammatory drug treatment resulted in reduced cellulitis. A 3-week regimen that included empirical antimicrobial treatment and improved husbandry resulted in resolution of the respiratory sounds and partial healing of bite wounds, but radiographic evaluation revealed progressive maxillary osteomyelitis. Microbial culture of blood yielded scant gram-positive cocci and Bacillus spp, which were suspected sample contaminants. Bilateral partial maxillectomies were performed; microbial culture and histologic examination of resected bone confirmed osteomyelitis with gram-positive cocci. Treatment with trimethoprim-sulfamethoxazole was initiated on the basis of microbial susceptibility tests. Four months later, follow-up radiography revealed premaxillary osteomyelitis; surgery was declined, and treatment with trimethoprim-sulfamethoxazole was reinstituted. Eight months after surgery, the patient was reevaluated because of recurrent clinical signs; premaxillectomy was performed, and treatment with trimethoprim-sulfamethoxazole was prescribed on the basis of microbial culture of bone and microbial susceptibility testing. Resolution of osteomyelitis was confirmed by CT 11 months after the initial surgery. CONCLUSIONS AND CLINICAL RELEVANCE Focal maxillectomies and premaxillectomy were successfully performed in a large python. Surgical management and appropriate antimicrobial treatment resulted in a good outcome.

Retrospective comparison of thromboelastography results to postmortem evidence of thrombosis in critically ill dogs: 39 cases (2005-2010).

OBJECTIVE: To determine whether there is an association between thromboelastography (TEG) data and necropsy evidence of thrombosis in a cohort of critically ill dogs. DESIGN: Retrospective study (2005-2010). SETTING: University teaching hospital. ANIMALS: Thirty-nine client-owned critically ill dogs for which TEG was performed within 7 days of complete necropsy. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Thrombi were found in 26 (67%) dogs. Spayed females (n = 20) were significantly more likely to have thrombosis (P = 0.0127). No significant association was found between presence of thrombosis and any TEG parameter, the calculated coagulation index, results of coagulation testing, type of vascular access, or clinical diagnosis. D-dimers were significantly higher in dogs with thrombosis (P = 0.0207) and a weak positive correlation was found between D-dimer value and number of sites of thrombosis (ρ = 0.18, P = 0.0045). Dogs with WBC > 16 × 10(3) /µL were more likely to have thrombosis compared to others (odds ratio 5.56, 95% confidence interval 1.2-25.7, P = 0.025). CONCLUSIONS: This study found no association between any TEG parameter and the presence of thrombosis on postmortem examination.

Benign cementoblastoma (true cementoma) in a cat.

CASE SUMMARY: A 10-year-old castrated male domestic shorthair cat was presented for assessment of a gingival mass surrounding the left maxillary third and fourth premolar teeth. The mass was surgically removed by means of a marginal rim excision, and the tissue was submitted for histological assessment. It was identified as a benign cementoblastoma (true cementoma). There was proliferation of mineralized eosinophilic material with multiple irregularly placed lacunae and reversal lines, reminiscent of cementum. The cat recovered uneventfully from the anesthesia, and there was no evidence of tumor recurrence 6 months after surgery. RELEVANCE AND NOVEL INFORMATION: Cementoblastomas (true cementomas) in domestic animals are rare, with just a few reports in ruminants, monogastric herbivores and rodents. Cementoblastoma is considered a benign tumor that arises from the tooth root. The slow, expansive and constant growth that characterizes these masses may be accompanied by signs of oral discomfort and dysphagia. This case report is intended to increase knowledge regarding this tumor in cats and also highlights the importance of complete excision of the neoplasm. To our knowledge, there are no previous reports in the literature of cementoblastoma in the cat.

Complete tissue coverage achieved by scaffold-based tissue engineering in the fetal sheep model of Myelomeningocele.

Myelomeningocele (MMC) is the most severe form of spina bifida, one of the most common congenital anomalies. Although open fetal surgical repair of the MMC defect has been shown to result in improved outcomes, a less invasive approach applicable earlier in gestation than the current open surgical approach between 19 and 26 weeks of gestation is desirable for further improvement of neurological symptoms, as well as reduction of maternal and fetal risks. We previously reported the therapeutic potential of a scaffold-based tissue engineering approach in a fetal rat MMC model. The objective of this study was to confirm the long-term efficacy of this approach in the surgically created fetal sheep MMC model. Gelatin-based or gelatin/collagen hybrid sponges were prepared with and without basic fibroblast growth factor (bFGF) incorporation. The defect was covered by a sponge and secured by a supporting sheet with adhesive at 100 days of gestation or the gelatin/collagen hybrid with bFGF was secured with adhesive without the sheet. Although sheets were found detached at term (140 days' gestation), both gelatin-based and gelatin/collagen hybrid sponges had integrated within the newly formed granulation tissue, resulting in complete coverage of the MMC defect. The release of bFGF from sponges resulted in enhanced formation of granulation tissue and epithelialization. There was also evidence of improved preservation of the spinal cord with less associated damage on histological analysis and reversal of hindbrain herniation. These experiments provide important proof-of-principle evidence of the efficacy of scaffold-based tissue engineered coverage for the prenatal treatment of MMC.

Feline Oral Squamous Cell Carcinoma: Clinical Manifestations and Literature Review.

Squamous cell carcinoma (SCC) is the most commonly encountered malignant oral tumor in cats. The etiology of this locally invasive tumor is likely multifactorial. Several risk factors have been identified, including the use of flea collars, and a history of feeding canned food and canned tuna. Clinical signs vary depending on tumor location. The tumor commonly arises from the gingiva and mucosa of the maxilla, mandible, tongue, sublingual area, or tonsillar region. Maxillary SCC commonly presents clinically as an ulcerative lesion, whereas mandibular SCC is commonly proliferative, expansile, and firm. Lingual/sublingual SCC may be ulcerative, necrotic, infiltrative, or proliferative. In general, feline oral SCC is an invasive and malignant neoplasm regardless of its location. Surgery, radiation therapy, chemotherapy and combinations thereof have been attempted with rarely a satisfactory response. Currently, cures are obtained only in a small subset of cats whose tumors are amenable to complete resection, or where resection with microscopic residual disease is followed by definitive radiation therapy. A multimodal treatment approach likely offers the best chance of success. For cats with advanced disease, palliative care may improve patients' quality of life, albeit transiently. Sequelae associated with tumor progression and local tissue destruction often result in euthanasia of feline patients with oral SCC.

Surgical correction of a sacral meningomyelocele in a dog.

A 15 wk old male unilateral cryptorchid German shepherd dog weighing 18 kg was referred for a nonhealing cutaneous lesion dorsally at the level of the sacrum, urinary incontinence, and a deviated tail. MRI revealed spina bifida and meningomyelocele continuous with the skin surface. Surgical correction of the meningomyelocele involved closure of the open meningeal defect, transection of the abnormal spinal nerves to the skin surface, and closure of the skin defect with a good outcome. Histopathology confirmed a meningomyelocele. This case report describes the MRI findings, surgical procedure, and proposed pathogenesis of spina bifida and meningomyelocele in a dog.

Deficiency of melanoma differentiation-associated protein 5 results in exacerbated chronic postviral lung inflammation.

RATIONALE: Respiratory viral infections can result in the establishment of chronic lung diseases. Understanding the early innate immune mechanisms that participate in the development of chronic postviral lung disease may reveal new targets for therapeutic intervention. The intracellular viral sensor protein melanoma differentiation-associated protein 5 (MDA5) sustains the acute immune response to Sendai virus, a mouse pathogen that causes chronic lung inflammation, but its role in the development of postviral chronic lung disease is unknown. OBJECTIVES: To establish the role of MDA5 in the development of chronic lung disease. METHODS: MDA5-deficient or control mice were infected with Sendai virus. The acute inflammatory response was evaluated by profiling chemokine and cytokine expression and by characterizing the composition of the cellular infiltrate. The impact of MDA5 on chronic lung pathology and function was evaluated through histological studies, degree of oxygen saturation, and responsiveness to carbachol. MEASUREMENTS AND MAIN RESULTS: MDA5 deficiency resulted in normal virus replication and in a distinct profile of chemokines and cytokines that associated with acute lung neutropenia and enhanced accumulation of alternatively activated macrophages. Diminished expression of neutrophil-recruiting chemokines was also observed in cells infected with influenza virus, suggesting a key role of MDA5 in driving the early accumulation of neutrophils at the infection site. The biased acute inflammatory response of MDA5-deficient mice led to an enhanced chronic lung inflammation, epithelial cell hyperplasia, airway hyperreactivity, and diminished blood oxygen saturation. CONCLUSIONS: MDA5 modulates the development of chronic lung inflammation by regulating the early inflammatory response in the lung.

Computed tomographic characteristics of odontogenic neoplasms in dogs.

Odontogenic neoplasms are locally invasive oral tumors in dogs. The purpose of this retrospective study was to describe CT characteristics for varying histopathologic types of canine odontogenic neoplasms. A board-certified veterinary radiologist who was unaware of histologic findings reviewed and scored imaging studies. A total of 29 dogs were included in the study. Twenty-three of these dogs had concurrent dental radiographs. The most common CT characteristics for all tumor types were a direct association with or in the region of multiple teeth in 96.4% (27/28), contrast enhancement in 96.3% (26/27), alveolar bone lysis in 93.1% (27/29), and mass-associated tooth displacement in 85.2% (23/27). Mass-associated cyst-like structures were identified in 53.6% (15/28) and were only present in tumors containing odontogenic epithelium. Canine acanthomatous ameloblastomas (n = 15) appeared as extra-osseous (10/15) or intra-osseous (5/15) masses. Intra-osseous canine acanthomatous ameloblastomas were more likely to have mass-associated cyst-like structures and were subjectively more aggressive when compared with extra-osseous canine acanthomatous ameloblastomas. Amyloid-producing odontogenic tumors (n = 3) had subjectively uniform CT imaging characteristics and consisted of round soft tissue and mineral attenuating masses with multiple associated cyst-like structures. Fibromatous epulides of periodontal ligament origin (n = 4) were contrast enhancing extra-osseous masses that were rarely referred for CT examinations and 25% (1/4) were not visible with CT. Other odontogenic tumors were less represented or had more variable CT imaging characteristics. Mass-associated tooth destruction was appreciated more often with dental radiographs and extra-oral tumor extension was identified more often with CT.

Cytologic features of clear cell adnexal carcinoma in 3 dogs.

BACKGROUND: Clear cell adnexal carcinoma is a rare cutaneous adnexal neoplasm without definitive apocrine, sebaceous, or follicular differentiation. Differential diagnoses include sebaceous carcinoma, liposarcoma, and balloon cell melanoma. Immunohistochemical analysis, with positive immunoreactivity for pancytokeratin and vimentin, aids in the diagnosis. Cytologic features of clear cell adnexal carcinoma have not been described previously. OBJECTIVE: The aim of this study was to describe cytologic features of canine clear cell adnexal carcinoma. METHODS: Fine-needle aspirates (FNA) obtained prior to biopsy of cutaneous neoplasms with a histologic diagnosis of clear cell adnexal carcinoma confirmed by immunohistochemical analysis were reviewed retrospectively. Slides prepared from FNA had been stained with modified Wright-Giemsa or automated aqueous Romanowsky stain. RESULTS: Of 20 neoplasms diagnosed as clear cell adnexal carcinoma in dogs, FNA of the mass had been performed in 3 cases. Cytologic features were similar and included high cellularity, marked cellular pleomorphism, loose arrangement of neoplastic cells, and a light blue to gray background resulting from streaming of cytoplasm from ruptured cells. Neoplastic cells were oval to polygonal to spindle-shaped with wispy cytoplasmic projections. Cytoplasmic eosinophilic stippling, globular deposits, or pink needle-shaped inclusions were noted. Criteria of malignancy included marked anisocytosis, anisokaryosis and anisonucleoleosis, multinucleation, karyomegaly, macronucleoli, and atypical mitotic figures. CONCLUSIONS: Clear cell adnexal carcinoma should be included in the cytologic differential diagnosis for a canine cutaneous mass even if an epithelial origin is not readily identified owing to lack of characteristic epithelial features, such as highly cohesive cell clusters, evident cell-to-cell junctions, and distinct cytoplasmic edges.