What is your diagnosis? Peritoneal effusion from a dog.

A 5-year-old, female Italian hound dog was presented with progressive weight loss, anorexia, and lethargy. Physical examination abnormalities included poor body condition, abdominal distension, splenomegaly, and areas of crusty alopecia on the head and limbs. Clinicopathologic abnormalities included mild normocytic normochromic anemia, moderate hyperproteinemia and hyperglobulinemia, mild hypoalbuminemia, and hyponatremia, a mild increase in serum alkaline phosphatase activity, and a moderate to marked increase in beta- and gamma-globulins on serum protein electrophoresis. Abdominal ultrasonography revealed peritoneal effusion. Abdominocentesis yielded approximately 200 mL of serosanguinous, slightly turbid fluid with 2.6 x 10(9) nucleated cells/L, and a protein concentration of 32 g/L. Cytologic specimens of the fluid contained a mixed population of inflammatory cells. Intracytoplasmic inclusions identified as Leishmania sp. amastigotes were observed in numerous macrophages and also free in the background. An ELISA for canine Leishmania sp. antibody was positive. The abdominal effusion resolved within a few days of beginning treatment with meglumine antimoniate and allopurinol. Finding Leishmania amastigotes in peritoneal fluid is rare in canine leishmaniasias and allows an easy, quick diagnosis of the disease.

Hemolytic-uremic syndrome in a dog.

A 3-year-old, spayed, female Boxer was presented because of acute onset of anorexia, vomiting, and hemorrhagic diarrhea. Microangiopathic hemolytic anemia with intravascular hemolysis, thrombocytopenia, and acute renal failure were detected. The dog was treated with fluids, antiemetics, antibiotics, and diuretics. Despite supportive therapy, the dog's condition worsened, and the owners elected euthanasia. Necropsy revealed disseminated petechiae on the parietal peritoneum and serosal surfaces of the intestinal tract. The histologic lesions were consistent with severe arteritis and microvascular thrombosis involving only the renal and intestinal arterioles. The final diagnosis was hemolytic-uremic syndrome (HUS), a rarely described disorder in dogs. The clinical presentation of primarily gastrointestinal clinical signs was similar to that of typical or diarrhea-associated HUS (D+ HUS) in humans (mainly children), which is caused by gastrointestinal proliferation of verocytotoxin-producing Escherichia coli. Bacterial toxins can be adsorbed and cause endothelial injury, activation of hemostasis, and thrombosis, with lesions confined primarily to the kidneys. Although rare, HUS should be considered in the differential diagnosis of dogs with microangiopathic hemolytic anemia.

Canine angiosarcoma: cytologic, histologic, and immunohistochemical correlations.

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

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 neuronspecific 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.

Use of real-time quantitative PCR to document successful treatment of Mycoplasma haemocanis infection with doxycycline in a dog.

An 8-year-old Jack Russell Terrier was diagnosed with hemolytic anemia caused by hemoplasmosis 4 years following splenectomy. Quantitative real-time PCR (qPCR) analysis was used initially to confirm infection with Mycoplasma haemocanis and subsequently to monitor and direct medical therapy. Doxycycline was administered beyond resolution of clinical signs until hemoplasma DNA could no longer be detected by qPCR. The dog remained clinically healthy and hemoplasma-negative 8 months following cessation of therapy. Canine hemoplasmosis should remain as a differential diagnosis for hemolytic anemia in dogs, particularly those that are splenectomized or immunocompromised, even in geographic regions where prevalence of infection is low. Prolonged doxycycline administration has been shown by qPCR to lead to sustained absence of detectable infection and should be considered as a first line treatment for canine hemoplasmosis.