Canine Clitoral Carcinoma: A Clinical, Cytologic, Histopathologic, Immunohistochemical, and Ultrastructural Study.

Vaginal and vulvar tumors are uncommon in dogs. Knowledge of canine primary clitoral neoplasia is restricted to a few case reports, and only carcinomas have been reported. Cytologic and histologic features reported in the literature seem to overlap with those of canine apocrine gland anal sac adenocarcinoma (AGASA). Clinical features also recall those of canine AGASA, such as locoregional metastases and hypercalcemia of malignancy (HM). In this study, 6 cases of primary canine clitoral carcinomas (CCCs), with and without HM, were investigated by means of cytology, histopathology, electron microscopy, and immunohistochemistry for neuroendocrine markers including chromogranin A (CGA), synaptophysin (SYN), neuron-specific enolase (NSE), and S-100. In all 6 tumors, cytologic findings were consistent with malignant epithelial neoplasia of apocrine gland origin. The tumors examined were classified into 3 different histological patterns representing different degrees of differentiation: tubular, solid, and rosette type. Both CGA and SYN were mildly expressed in 2 of 6 tumors, while NSE was consistently expressed in all 6 cases. None of the tumors were S-100 positive. Transmission electron microscopy revealed electron-dense cytoplasmic granules compatible with neuroendocrine granules in all 6 cases. CCCs presented clinicopathologic features resembling AGASAs with neuroendocrine characteristics, and 2 of 6 neoplasms were considered as carcinomas with neuroendocrine differentiation and were positive for 3 neuroendocrine markers. CCCs can often present with HM, and long-term outcome is likely poor. Our study concludes that CCC seems to be a rare tumor, but it might be underestimated because of the overlapping features with AGASA. Further studies should aim to define the true incidence of this disease.

Persistent marked cerebrospinal fluid eosinophilia in a dog with primary central nervous system histiocytic sarcoma.

A 6-year-old female spayed Jack Russell Terrier was evaluated for episodic seizure-like activity and intermittent obtundation over the previous 3 weeks. Magnetic resonance imaging (MRI) of the brain revealed mild generalized dilation of the ventricular system with periventricular edema. A focal area of mildly increased lepto- and pachymeningeal contrast uptake in the region of the right parietal and occipital lobes was observed. Analysis of cerebrospinal fluid (CSF) revealed marked mixed pleocytosis with 20% eosinophils and no atypical cells or microorganisms. The dog transiently improved with prednisolone for suspected eosinophilic meningoencephalitis/meningoencephalomyelitis of unknown origin (MUO) but worsened over the following 5 months. Brain MRI and CSF sampling were repeated. Additional multifocal lesions were evident in the brainstem and cerebellum. On CSF analysis, the eosinophilic pleocytosis and increased total protein persisted. The clinical signs progressed despite treatment, and the patient was euthanized 6 weeks later. A post-mortem examination was performed. Histopathology and immunohistochemistry revealed a multifocal neoplastic proliferation of cells in the brain, diffusely and strongly positive for ionized calcium-binding adapter molecule (Iba-1) and negative for AE1/AE3 pan-cytokeratin and glial-fibrillar-acid-protein (GFAP) immunostaining, consistent with a diagnosis of histiocytic sarcoma (HS). No other organic lesions were found; therefore, the neoplasm was considered a primary HS of the central nervous system (CNS). This case report stresses the importance of considering primary CNS HS in the differential diagnosis of dogs with marked CSF eosinophilia, even in the absence of atypical cells on cytologic examination.

Unedited allogeneic iNKT cells show extended persistence in MHC-mismatched canine recipients.

Allogeneic invariant natural killer T cells (allo-iNKTs) induce clinical remission in patients with otherwise incurable cancers and COVID-19-related acute respiratory failure. However, their functionality is inconsistent among individuals, and they become rapidly undetectable after infusion, raising concerns over rejection and limited therapeutic potential. We validate a strategy to promote allo-iNKT persistence in dogs, an established large-animal model for novel cellular therapies. We identify donor-specific iNKT biomarkers of survival and sustained functionality, conserved in dogs and humans and retained upon chimeric antigen receptor engineering. We reason that infusing optimal allo-iNKTs enriched in these biomarkers will prolong their persistence without requiring MHC ablation, high-intensity chemotherapy, or cytokine supplementation. Optimal allo-iNKTs transferred into MHC-mismatched dogs remain detectable for at least 78 days, exhibiting sustained immunomodulatory effects. Our canine model will accelerate biomarker discovery of optimal allo-iNKT products, furthering application of MHC-unedited allo-iNKTs as a readily accessible universal platform to treat incurable conditions worldwide.

Comparison of effusion cell block and biopsy immunohistochemistry in mesothelial hyperplasia, mesothelioma, and carcinoma in dogs.

BACKGROUND: Determining the cause of effusions is challenging and might require a biopsy. Whether cell blocks from effusions are representative of biopsies requires investigation. A previously developed immunohistochemical panel aids in the differentiation of hyperplastic and neoplastic mesothelium in canine biopsies but has not been investigated in effusions. OBJECTIVES: The study aimed to assess cell blocks as an alternative to biopsies and determine whether immunohistochemistry helps distinguish hyperplastic mesothelium, mesothelioma, and carcinoma. METHODS: Effusions and biopsies were collected from five dogs with mesothelial hyperplasia (group MH), six with mesothelioma (group M), and five with carcinoma (group C). Immunohistochemistry (IHC) for cytokeratin, vimentin, Wilm's tumor protein 1 (WT1), desmin, glucose transporter 1 (GLUT1), and insulin-like growth factor II mRNA-binding protein 3 (IMP3) was performed. Sections were scored for staining intensity and the percentage of positively stained cells. RESULTS: In paired cell blocks and biopsies, vimentin and WT1 staining were positively correlated for intensity and the percentage of positive cells, although not all paired results were identical. The intensity of IMP3 staining in cell blocks was higher in group M than in group C (P = 0.012), and WT1 staining was higher in group MH than in group C (P = 0.020). For biopsies, the intensity of WT1 staining was higher in group MH than in group C (P = 0.031). In group C, WT1 was negative in all cell blocks and biopsies, and desmin was negative in four of five cases. CONCLUSIONS: IHC results for the cell blocks and biopsies were comparable for potentially useful markers, such as WT1, which helped discriminate between groups. IHC provided additional information, although results were not always definitive. Further studies on a larger population are required.

CT-guided drainage of a brainstem abscess in a cat as an emergency treatment procedure.

CASE SUMMARY: A 3-year-old male neutered domestic shorthair cat was presented with a 1-week progressive and rapidly deteriorating history of lethargy and abnormal behaviour. Neurolocalisation indicated multifocal intracranial lesions (right oculomotor nerve, brainstem [obtundation, non-ambulatory tetraparesis, vestibular dysfunction and intermittent decerebrate rigidity] and possibly the thalamus [left-sided pleurothotonus]), or more likely a single brainstem lesion with mass effect. MRI of the brain demonstrated a brainstem abscess causing severe dorsal displacement particularly affecting the pons and the medulla oblongata causing cerebellar vermis herniation through the foramen magnum. CT-guided free-hand technique drainage of the brain abscess was performed and broad spectrum antibiotics were started based on sensitivity results. The cat recovered uneventfully from anaesthesia displaying marked improvement immediately after the procedure. Antibiotics were continued for 8 months; repeat imaging prior to withdrawal found complete resolution of the brainstem abscess. RELEVANCE AND NOVEL INFORMATION: Free-hand CT-guided drainage of a brainstem abscess is not without risk; however, in this case it led to significant clinical improvement and stabilisation likely owing to reduced intracranial pressure. It also provided a diagnostic sample that allowed successful medical treatment planning and outcome. To our knowledge, this is the first report describing the successful management of a brainstem abscess by CT-guided drainage in the veterinary literature. It suggests that stereotactic drainage followed by medical therapy can be considered a successful therapeutic alternative to brain surgery or medical treatment alone, providing an emergency treatment in cases of acute brainstem dysfunction.

Eosinophilic cerebrospinal fluid pleocytosis associated with neural Angiostrongylus vasorum infection in a dog.

A 1-year-old, female intact Pug dog was presented to the Small Animal Teaching Hospital of the University of Liverpool with a 4-week history of progressive multifocal intracranial signs. Magnetic resonance imaging (MRI) detected multiple hemorrhagic lesions in the brain. The Baermann and zinc sulfate flotation tests with centrifugation, performed on fecal samples, were positive for lungworm larvae and an antigenic test confirmed Angiostrongylus vasorum infection. Anthelmintic treatment was started with a consequent marked clinical improvement. Seventy days later, the dog was clinically normal, and no larvae were detected on the Baermann test. Repeat MRI of the brain revealed marked improvement of the hemorrhagic lesions. Cerebrospinal fluid analysis (CSF) showed marked eosinophilic pleocytosis, and anthelmintic treatment was restarted. A follow-up CSF analysis 4 months after the first presentation revealed resolution of the eosinophilic pleocytosis. This is the first case report of marked eosinophilic pleocytosis associated with neural A vasorum infection in a dog. The CSF eosinophilic pleocytosis persisted for several weeks after treatment, even in the absence of concurrent clinical signs and with a negative A vasorum Baermann test.

Are serum amyloid A or D-lactate useful to diagnose synovial contamination or sepsis in horses?

Synovial sepsis in horses is life threatening and accurate diagnosis allowing prompt treatment is warranted. This study assessed the diagnostic value of serum amyloid A (SAA) and D-lactate in blood and synovial fluid (SF) as diagnostic markers of synovial sepsis in horses and correlated them with total nucleated cell count (TNCC), percentage of neutrophils (%N) and total protein (TP) in SF. Blood and SF SAA and D-lactate concentrations were determined in a case-control observational study including 112 horses (38 with synovial contamination or sepsis (SCS), 66 with non-septic intra-synovial pathology (NSISP) and 8 controls). Blood and SF SAA were significantly higher in SCS than in NSISP and control horses. SAA values were similar in NSISP and control horses. SF SAA was moderately correlated with synovial TNCC, TP and blood SAA. Blood and SF SAA were 82.4 per cent and 80 per cent sensitive and 88.9 per cent and 73 per cent specific for diagnosis of SCS, with cut-off values of 60.7 and 1.14 µg/ml, respectively. Blood and SF D-lactate concentrations were not significantly different between groups. This study shows that blood and SF SAA concentrations can aid to distinguish SCS from non-septic synovial pathology; however, D-lactate was not useful.

Neoplastic pleural effusion and intrathoracic metastasis of a scapular osteosarcoma in a dog: a multidisciplinary integrated diagnostic approach.

A 10-year-old, female spayed mixed-breed or cross-bred dog was referred to the Small Animal Teaching Hospital of the University of Liverpool due to tachypnea, dyspnea, and pleural effusion not responding to diuretics and antibiotics. The chest was drained and cytology of the pleural fluid was consistent with a modified transudate with presence of atypical cells initially attributed to mesothelial hyperplasia and dysplasia. Computed tomography detected, in addition to the bilateral pleural effusion, diffuse pleural thickening, multiple pleural and pulmonary nodules, and a mineralized and lytic mass in the left scapula. Imaging findings were suggestive of a primary bone tumor with intrathoracic metastasis. Cytology of the left scapular and pleural masses revealed a malignant neoplasm highly suggestive of osteosarcoma. The diagnosis was confirmed by demonstration of a positive cytochemical reaction for alkaline phosphatase on prestained cytology slides. This finding prompted review of the initial interpretation of the pleural effusion cytology. The presence of neoplastic osteoblasts in the thoracic fluid was identified by a combination of cytochemistry, cell pellet immunohistochemistry, and transmission electron microscopy findings. In this report, a multidisciplinary integrated diagnostic approach was used to diagnose and confirm a neoplastic pleural effusion due to osteosarcoma metastasis in a dog.

Significance of mastocytemia in cats.

BACKGROUND: In cats, mastocytemia is considered to be confined to animals with mast cell tumors (MCT), whereas in dogs it is associated with diverse diseases. OBJECTIVE: The objective of this retrospective study was to investigate the diagnostic and prognostic significance of mastocytemia in cats. METHODS: All blood smears and buffy coat (BC) smears on which mast cells were identified over a 6-year period were retrospectively reviewed and mast cells counted. Mastocytemic cats were classified based on their clinical diagnosis. RESULTS: Mastocytemia was identified on 40 blood smears and 13 BC smears from 33 cats. The incidence of mastocytemia detected in cats during routine CBCs was 0.33% (40/12,116 CBCs). Twenty-two of 33 mastocytemic cats (67%) had visceral (n = 17) or cutaneous MCT (n = 7), including 2 that had concurrent visceral and cutaneous involvement. In 3 additional cases (9%), visceral MCT was clinically suspected, but no cytologic or histopathologic evaluation of visceral organs was performed. MCT was excluded in 3 of 33 mastocytemic cats (9%) with a final diagnosis of lymphoid neoplasia (n = 2) and multiorgan hemangiosarcoma (n = 1). Five additional animals (15%) had a diagnosis other than MCT, including lymphoma (n = 2) and chronic renal failure (n = 3), but no cytologic or histopathologic evaluation of the spleen was performed. Blood smears from cats with confirmed MCT had 1-113 mast cells per smear, whereas cats in which MCT was excluded had 1-2 mast cells per smear. CONCLUSIONS: Data confirm that mastocytemia is rare and most commonly found in cats with visceral MCT; however, rare circulating mast cells may also be seen with neoplasms other than MCT.

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.

Serum cardiac troponin I concentrations in dogs with leishmaniasis: correlation with age and clinicopathologic abnormalities.

BACKGROUND: There is anecdotal evidence of myocardial injury in dogs with leishmaniasis due to generalized vasculitis and myocarditis. OBJECTIVE: The aims of this study were to evaluate serum concentration of cardiac troponin I (cTnI) as an indicator of myocardial injury in dogs with leishmaniasis and to assess the relationship between cTnI concentration and age, serum antibody titer, and a variety of blood analytes. METHODS: In this retrospective study, serum cTnI concentration was measured in dogs with leishmaniasis and in age-matched healthy dogs. Diagnosis was based on clinical signs and moderate-to-high seropositivity for Leishmania as measured by ELISA. Correlations between cTnI concentration and ELISA seropositivity, PCV, concentrations of serum creatinine, total protein, albumin, and globulin, albumin:globulin ratio (A/G), and urine protein:creatinine ratio (UPC) were investigated. The Mann-Whitney test was used to compare analytes between dogs with normal and increased (> 0.06 µg/L) cTnI concentration and to compare cTnI concentrations between dogs with and without anemia, azotemia, and proteinuria. RESULTS: In dogs with leishmaniasis (n = 40), median cTnI concentration was higher than in control dogs (n = 11) (P = .011). Sixteen dogs (40%) with leishmaniasis had increased cTnI concentration; cTnI was moderately to weakly correlated with decreased albumin concentration, decreased A/G, increased UPC, decreased PCV, positive Leishmania titer, and increased age. Dogs with leishmaniasis had significantly higher total protein and globulin concentrations and lower PCV, albumin concentration, and A/G than control dogs. Hematologic and biochemical analytes did not differ significantly between dogs with cTnI concentration within the reference interval and those with increased concentrations. Concentration of cTnI was higher in proteinuric dogs compared with nonproteinuric dogs (P = .017). CONCLUSION: A proportion of dogs with leishmaniasis have increased serum cTnI concentration, indicative of some degree of cardiac injury. Additional studies are needed to investigate the relationship between leishmaniasis and possible myocardial injury.

Neutrophilic myeloperoxidase index and mean light absorbance in neonatal septic and nonseptic foals.

BACKGROUND: Two neutrophilic indices reported by the ADVIA 120 Hematology Analyzer, neutrophilic myeloperoxidase index (MPXI), and mean light absorbance (neutrophil X mean [NXM]) have been proposed as indicators of systemic inflammatory disease in horses and of neutrophil activation in coronary ischemic syndromes in people. OBJECTIVE: The aim of this study was to evaluate NXM and MPXI in healthy, sick nonseptic, and sick septic foals to determine whether conditions likely associated with neutrophil activation result in decreases in these variables. METHODS: In this retrospective study, CBC data from 61 neonatal foals presented to the Equine Teaching Hospital of Barcelona were evaluated for correlations between MPXI, NXM, percentage of large unstained cells, neutrophil count, and percentage of band neutrophils. Results obtained in septic (n=32), sick nonseptic (n=22), and healthy foals (n=7) were compared. In addition, results recorded in septic/neutropenic (n=12), septic/non-neutropenic (n=20), nonseptic/neutropenic (n=8), nonseptic/non-neutropenic (n=14), and healthy foals (n=7) were also compared. RESULTS: A weak negative correlation was found between MPXI and neutrophil count and between NXM and percentage of band neutrophils. Septic/neutropenic foals had significantly higher MPXI values (median 17.9, minimum-maximum 4.7-42.5) than did septic/non-neutropenic (1.5, -24.4 to 22.3), nonseptic/neutropenic (6.6, 0.6-17.9), and nonseptic/non-neutropenic foals (8.8, -10.1 to 16.8) but did not differ significantly from controls (12.8, -8.5 to 20.4). CONCLUSIONS: Significant differences in NXM or MPXI were not found when disease groups were compared with controls; however, septic/neutropenic foals had significantly higher median MPXI than other groups of sick foals. Further prospective studies are needed to clarify if this finding is related to decreased neutrophil function or activation in septic/neutropenic foals.