What is your diagnosis? Subcutaneous mass fluid from a febrile dog

Abstract: A 10‐month‐old spayed female Doberman Pinscher was presented for lameness. On physical examination, the dog was lethargic and febrile and had a 2‐cm raised subcutaneous mass at the base of the left ear. Fluid from the mass was drained. Direct smears of the fluid, stained with modified Wright's and new methylene blue, were highly cellular and contained large numbers of degenerate neutrophils with moderate numbers of macrophages. Large numbers of round yeast organisms, 8–20 μm in diameter, were observed extracellularly. The organisms had a thick blue wall and granular internal contents and broad‐based budding was seen frequently. Branching hyphae or pseudohyphae, with parallel sides and 2–4 μm in diameter, appeared to extend from the surface of the yeast. The morphology of the yeast organisms was consistent with Blastomyces dermatitidis, with atypical hyphae formation. Culture results were not definitive because it was not possible to induce transition from the mycelial to the yeast form at 37°C and because the morphology of the mycelial form of B. dermatitidis could not be differentiated from that of Emmonsia parvae. The organism was confirmed as Ajellomyces dermatitidis (the mycelial form of B. dermatitidis) using 18S ribosome RNA gene sequencing and comparison with an available databank. The mycelial form of B. dermatitidis is rarely found in the tissue of dogs, and may have been induced in this case by low environmental temperatures and the time delay between sample collection and slide preparation.     

What is your diagnosis? Particulate material in peritoneal fluid from a dog

9-year-old castrated male Greyhound dog was presented for evaluation of vomiting and lethargy of 1-week duration. On physical examination, the dog was febrile and dehydrated with a tense abdomen and petechial hemorrhages. Clinicopathologic abnormalities included relative polycythemia, mild lymphopenia with reactive lymphocytes, hypoalbuminemia, hypocholesterolemia, hyperbilirubinemia, increased ALP, mild hypokalemia, hyperamylasemia, hyperlipasemia, increased D-dimer concentration, and hyperfibrinogenemia. Cytologic evaluation of peritoneal fluid revealed marked suppurative inflammation with intracellular barium sulfate particles. The day before presentation, the referring veterinarian had administered oral barium sulfate in an upper gastrointestinal contrast study. Radiographs revealed free contrast material in the peritoneal cavity, consistent with gastrointestinal perforation, and leakage of contrast material. Abdominal exploratory surgery revealed a mid-jejunal perforation and a hepatic nodule. Histopathologic diagnosis of the jejunal and liver lesions was T-cell lymphoma. The patient recovered well postoperatively and received chemotherapy for treatment of lymphoma. Most commercial barium sulfate preparations contain relatively uniform, weakly birefringent, pale yellow particles <1 microm in diameter. Because barium sulfate is found occasionally in clinical specimens, cytopathologists should be familiar with its cytologic appearance.     

What is your diagnosis? Peritoneal effusion from a dog

Abstract: 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 β‐ and γ‐globulins on serum protein electrophoresis. Abdominal ultrasonography revealed peritoneal effusion. Abdominocentesis yielded ～200 mL of serosanguinous, slightly turbid fluid with 2.6 × 10⁹ 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.