Telangiectatic osteosarcoma in four dogs: Cytologic, histopathologic, cytochemical, and immunohistochemical findings.

Telangiectatic osteosarcoma is a rare variant of osteosarcoma histologically and clinically similar to hemangiosarcoma (HSA). This case series describes the imaging and cytologic features of four histologically confirmed telangiectatic osteosarcomas, including the use of cytochemical stains. Alkaline phosphatase (ALP) was applied to Wright-Giemsa-stained cytology slides, and Factor VIII immunohistochemistry was evaluated. Cytologic characteristics included atypical mesenchymal cells with evidence of acute and chronic hemorrhage. Telangiectatic osteosarcoma cases had positive ALP cytochemical staining, while control HSA cases were negative. Factor VIII immunohistochemistry was negative in telangiectatic osteosarcoma and positive in HSA. Cytologic diagnosis of telangiectatic osteosarcoma with positive ALP cytochemical staining can help differentiate this neoplasm from HSA.

Association of leukergy (in vitro leukocyte aggregation) with systemic inflammation in dogs and cats (2017-2022).

BACKGROUND: Leukergy is the phenomenon of aggregation of leukocytes on a peripheral blood film, and in humans, it is used as an indicator of systemic inflammation and infection. OBJECTIVES: To assess the association of leukergy on blood film examination with biochemical and clinical evidence of systemic inflammation, infection, neoplasia, or specific organ system disease. METHODS: A case-control study using retrospective analysis (2017-2022) identified all canine and feline patients that had been presented to an academic referral center with a finding of leukergy on peripheral blood film and an equal number of species-matched controls. RESULTS: A total of 127 cases (canine n = 44, feline n = 83) were identified, as well as 127 controls. Feline samples were 7.6× more likely to exhibit leukergy (0.019%) than canine (0.0025%). A positive association was noted between leukergy and higher globulin concentrations in dogs (marginal difference 0.5 mg/dL, P = .016) and cats (marginal difference 0.67 mg/dL, P = <.001). Cats with leukergy had higher WBC counts and were less likely to be diagnosed with cardiac or urinary tract disease than controls. Dogs with leukergy had lower WBC counts and were more likely to be febrile but were less likely to have urinary tract disease than controls. No association was found with neutrophil toxic change or band forms, systemic antimicrobial therapy, or signalment. CONCLUSIONS: We conclude that there is a positive association between increased globulin concentrations and leukergy and inconsistent associations between leukergy and other markers of inflammation or infection. Leukergy is rare overall but markedly more common in cats than dogs.

Abdominal ultrasonographic findings of cats with feline infectious peritonitis: an update.

OBJECTIVES: The aim of this study was to describe the abdominal ultrasonographic findings in cats with confirmed or presumed feline infectious peritonitis (FIP). METHODS: This was a retrospective study performed in an academic veterinary hospital. The diagnosis of FIP was reached on review of history, signalment, clinical presentation, complete blood count, biochemistry panel, peritoneal fluid analysis, cytology and/or histopathology results from abnormal organs, and/or molecular testing (immunohistochemical or FIP coronavirus [FCoV] RT-PCR). Cats with confirmed FIP by molecular testing or with a highly suspicious diagnosis of FIP were included. Abdominal ultrasound examination findings were reviewed. RESULTS: In total, 25 cats were included. Common clinical signs/pathology findings included hyperglobulinemia (96%), anorexia/hyporexia (80%) and lethargy (56%). Abdominal ultrasound findings included effusion in 88% and lymphadenopathy in 80%. Hepatic changes were noted in 80%, the most common being hepatomegaly (58%) and a hypoechoic liver (48%). Intestinal changes were noted in 68% of cats, characterized by asymmetric wall thickening and/or loss of wall layering, with 52% being ileocecocolic junction and/or colonic in location. Splenic changes were present in 36% of cats, including splenomegaly, mottled parenchyma and hypoechoic nodules. Renal changes were present in 32%, encompassing a hypoechoic subcapsular rim and/or cortical nodules. Mesenteric and peritoneal abnormalities were seen in 28% and 16% of cats, respectively. Most cats (92%) had two or more locations of abdominal abnormalities on ultrasound. CONCLUSIONS AND RELEVANCE: The present study documents a wider range and distribution of ultrasonographic lesions in cats with FIP than previously reported. The presence of effusion and lymph node, hepatic and/or gastrointestinal tract changes were the most common findings, and most of the cats had a combination of two or more abdominal abnormalities.

Spindle-cell thymoma colliding with a bronchogenic cyst in a Yorkshire terrier.

An 8-year-old male Yorkshire terrier was presented to the Tufts Veterinary Hospital for evaluation of increased respiratory effort. A mediastinal mass composed of a spindle-cell thymoma within a bronchogenic cyst was diagnosed with computed tomography thoracic imaging, ultrasound-guided fine-needle aspirate biopsy, and histopathologic evaluation after surgical removal. Histologic evaluation showed a multilocular cyst structure as well as a mass characterized by spindle to polygonal thymic epithelial cells. The cyst was characterized by a lining of ciliated pseudostratified respiratory epithelium. To the authors' knowledge, this is the first report of a spindle-cell thymoma being associated with a mediastinal bronchogenic cyst in a dog.

Vulval apocrine adenocarcinoma with tumour-associated eosinophilia in a cat.

A 10-year-old, spayed female, Domestic Shorthaired cat was referred for surgical removal of a mass on the left vulval fold. An impression smear revealed mixed cell inflammation, with eosinophils predominating focally, and a concurrent bacterial infection, suggesting a primarily inflammatory lesion. However, cytology of a fine-needle aspirate of the mass revealed a neoplastic epithelial cell population, confirmed on histopathology as an apocrine vulval adenocarcinoma with lymphatic invasion and marked tumour-associated tissue eosinophilia. One month after surgical excision of the mass, the cat developed inguinal metastatic lymphadenopathy and chemotherapy was initiated. The patient ultimately developed marked peripheral lymphadenomegaly and was euthanized due to concerns for overall quality of life and comfort. This case highlights that neoplasia should be a consistent differential diagnosis for eosinophilic infiltrates/inflammation. The distinct appearance of the two cytological samples in this case stresses the need for sampling of different sites of a lesion and the importance of not relying on superficial impression smears for clinical management and prognosis.

Equine Granulocytic Anaplasmosis.

Equine granulocytic anaplasmosis is a clinically significant and common disease of equids that has a broader prevalence than was once thought. The most common clinical signs include high fever and edema, with mild to mderate thrombocytopenia and lymphopenia typically noted on complete blood count. Subclinical cases are reported and many are self-limiting. Rare clinical presentations include neurologic disease, vasculitis, dysphagia, rhabdomyolysis, or bicavitary effusion. Most cases resolve rapidly with appropriate antimicrobial intervention.

Infection with the fox lungworm (Crenosoma vulpis) in two dogs from New England - Two clinical reports and updated geographic distribution in North America.

Crenosoma vulpis, the fox lungworm, is a helminth parasite endemic to the fox population of New England. Domestic dogs are susceptible to infection via ingestion of snails and slugs. Two dogs from New England were diagnosed with C. vulpis. The predominant clinical sign in both dogs was a chronic cough. Treatment with steroids and antibiotics only temporarily relieved clinical signs. Thoracic radiographs in both dogs revealed bronchial patterns. Endotracheal washes were performed in each dog revealing marked, mixed inflammation consisting mainly of neutrophils with eosinophils in lesser numbers. Helminth larvae could also be visualized on cytology. A fecal flotation revealed helminth larvae in one dog but failed to identify larvae in the second dog. The diagnosis of C. vulpis was confirmed via PCR analysis and sequencing of samples from both endotracheal washes. One dog was treated with fenbendazole (50 mg/kg PO q24h for 14 days), enrofloxacin (13 mg/kg PO q 24 h for 5 days), and a tapering protocol of prednisone (20 mg PO q12h for 5 days, 20 mg PO q24h for 5 days, then 20 mg PO q48h for 10 days). The second dog was treated with fenbendazole (50 mg/kg PO q24h for 10 days) with an additional 7 days of febantel and two doses of milbemycin, achieving complete resolution of clinical signs. This lungworm is becoming increasingly more prevalent in domestic dogs worldwide and may be more prevalent in New England than previously thought. Veterinary practitioners of New England should include this respiratory helminth as a differential in dogs with respiratory signs, and respiratory washes and Baermann fecal examinations are warranted in dogs presenting with non-specific respiratory clinical signs.

Cytologic, histopathologic, and clinical features of granulomatous colitis in a French Bulldog.

A young French Bulldog was presented with clinical signs of chronic gastrointestinal disease, unresponsive to medical therapies. Parasite screenings and abdominal ultrasound failed to identify the etiology of the clinical signs. Cytologic evaluation of a rectal scraping sample diagnosed presumptive granulomatous colitis (GC) based on the presence of numerous macrophages with characteristic abundant, pink, granular cytoplasm, which showed an intense pink color when stained with periodic acid-Schiff. Tissue biopsy samples and Escherichia coli fluorescence in situ hybridization analysis confirmed the cytologic diagnosis. The cytologic, histopathologic, and clinical features and staining properties of GC in a French Bulldog are reported. Rectal scraping should be considered a part of the diagnostic evaluation in patients with suspected GC.

Intracoelomic Teratoma in an Eclectus Parrot (Eclectus roratus).

A 26-year-old, male eclectus parrot (Eclectus roratus) was presented to its primary care veterinarian for a 10-day history of increased respiratory effort, lethargy, and a single episode of regurgitation. Hepatomegaly, proventricular enlargement, cranial displacement of the ventriculus, and coelomic effusion were suspected based on a 1-view radiographic image, and the patient was referred for further evaluation. On presentation to the referral veterinary hospital, a distended coelom and dyspnea with abnormal respiratory sounds were abnormalities noted upon physical examination of the patient. The bird was hospitalized for supportive care, and diagnostic tests were performed. Initial radiographic images at the referral hospital revealed a large intracoelomic mass. A computed tomographic scan was performed; however, the origin of the mass could not be determined. A fine-needle aspirate and cytologic evaluation of the intracoelomic mass revealed a neoplastic process but no specific tissue type. Two days after presentation to the referral hospital, an exploratory coeliotomy to surgically resect the mass was attempted. The mass occupied most of the coelomic cavity, with multiple adhesions to internal organs. The mass was successfully resected; however, the patient destabilized and died despite resuscitation efforts. Histopathologic examination of submitted tissue from the mass with immunohistochemistry revealed mixed populations of neoplastic cells differentiated from 3 primordial germinal layers, confirming the diagnosis of teratoma. Teratomas appear to be a rare tumor in avian species but should be included in a list of differential disease diagnoses for abnormal tissue masses of unknown origin. Only 2 cases of teratomas have, to our knowledge, been reported in psittacine species.

Fluid Analysis in the Equine Patient: Cerebrospinal, Synovial, and Peritoneal Fluids.

Fluid analysis is an important part of the diagnostic work-up of equine patients presenting with disorders of the nervous system, musculoskeletal system, and abdominal cavity. Proper specimen handling and processing are paramount for complete and accurate interpretation of fluid samples. Normal cerebrospinal fluid is a low-cellularity, low-protein fluid requiring specific sample handling to ensure accurate results. Joint and abdominal fluid analyses are completed in practice or submitted for analysis to a reference laboratory. This article discusses fluid sample handling and processing considerations for the equine practitioner and reviews cytologic evaluation of normal and abnormal cerebrospinal, synovial, and peritoneal fluid samples.

Circulating melanin-containing cells and neutrophils with phagocytized melanin granules in a horse with disseminated melanoma.

An 18-year-old, grey, Thoroughbred Cross gelding was referred to the Cummings School of Veterinary Medicine at Tufts University following a 3-week history of low-grade fever of unknown origin, distal limb swelling, and weight loss. Clinical examination identified a few black, round, smooth nodules along the ventral aspect of the proximal tail. Transabdominal ultrasound showed a markedly enlarged heterogenous spleen, hyperechoic liver nodules, and evidence of peritonitis with fibrin deposition. A mature neutrophilia was noted on complete blood count with variable numbers of phagocytized granules within neutrophils. The granules did not stain with Perl's Prussian blue, and were intensely positive when stained with Fontana-Mason, consistent with melanin. On necropsy, the spleen occupied approximately one-third of the abdominal cavity and was diffusely firm with abundant black pigment on cut section. The medullary space of the 18th thoracic vertebra was also diffusely blackened. The splenic, mediastinal, and tracheobronchial lymph nodes were five times the normal size and diffusely pigmented. The final anatomic diagnosis was disseminated malignant melanoma with extensive splenic involvement and hemolymphatic and vascular neoplastic dissemination. To the authors' knowledge, this is the first full report to identify circulating neutrophils containing phagocytized melanin granules, which confirmed an antemortem diagnosis of disseminated melanoma.