An unusual case of giant cell tumor of soft parts in an American Warmblood horse.

Fine needle aspiration and tissue biopsy samples were taken from a subcutaneous mass in the cranial stifle region of a 10-yr-old horse. Key cytologic features included numerous mildly to moderately pleomorphic histiocytic cells admixed with mononuclear inflammatory cells, occasional fibroblasts, multinucleated cells, and hemosiderin-laden macrophages. Based on these features, cytologic differentials included granulomatous inflammation with reactive fibroplasia, histiocytic sarcoma, giant cell tumor of soft parts (GCTSPs), and giant cell tumor of bone. The tissue biopsy supported a diagnosis of superficial GCTSPs. This neoplasm is of controversial origin but generally considered to be a soft tissue sarcoma and classified in the World Health Organization classification of tumors under fibrous histiocytic tumors as a giant cell tumor of soft tissue with low risk of malignancy. When found in the subcutis, this neoplasm rarely metastasizes in the horse and has a low rate of local reoccurrence. In this case, there was no local recurrence of the tumor after 6 mo, after which the horse was lost to follow-up.

Immunolocalization of novel corticomedullary tubule injury markers in Cynomolgus monkeys treated with amphotericin B.

Amphotericin B (AmpB) nephrotoxicity was used to assess the utility of drug­induced kidney injury (DIKI) biomarkers in an exploratory study in male cynomolgus monkeys. All animals had quantifiable levels of AmpB in plasma on days 1 and 4. There were no clinical signs of AmpB­induced toxicity in this study. The gold standard method used to confirm AmpB­induced DIKI was anatomic pathology which revealed microscopic lesions with varying grades of severity. Immunolocalization of alpha­1 microglobulin (α­1M), kidney injury molecule 1 (KIM­1), osteopontin (OPN) and neutrophil gelatinase­associated lipocalin (NGAL) proteins was evaluated in formalin­fixed, paraffin­embedded monkey kidney tissue sections. AmpB related immunoreactivities were identified in distinct nephron segments of treated monkeys including α­1M in damaged proximal tubule epithelium, KIM­1 in damaged medullary tubule epithelium, OPN mostly in the infiltrating cells of cortical tubule interstitium, and NGAL in the granular and cellular cast in dilatated cortical tubules. Variations in α­1M, KIM­1, OPN and NGAL immunolocalization appear as promising DIKI protein biomarkers when monitoring for AmpB­induced corticomedullary tubule injury in male cynomolgus monkeys.

Improved clinicopathologic assessments of acute liver damage due to trauma in Indian ring-necked parakeets (Psittacula krameri manillensis).

Increased activities of certain biochemical enzymes (alanine aminotransferase [ALT], aspartate aminotransferase [AST], lactate dehydrogenase [LDH], alkaline phosphatase [ALP]) have been associated with blunt liver injury in many species. To evaluate changes in plasma hepatic biochemical parameters in acute avian liver disease caused by trauma and to compare biochemical changes with histologic lesions in hepatic parenchyma, 30 healthy fasted Indian ring-necked parakeets (Psittacula krameri manillensis) were divided into 2 groups, and traumatic liver injury was caused by endoscopic liver biopsy (group 1) or by liver biopsy and crushing injury to the hepatic parenchyma with endoscopic forceps (group 2) in anesthetized birds. Blood samples were collected at baseline and at 12, 24, 36, 48, 60, 72, 84, 96, 108, and 120 hours in alternate groups to compare analyte values after injury with those at baseline. Results showed consistently decreased plasma ALP activity (excluding 1 time point) throughout the study, which was thought to be associated with isoflurane administration. Plasma glutamate dehydrogenase activity initially increased but rapidly declined thereafter and was attributed to acute focal hepatocellular injury. In both groups, increases in plasma AST, ALT, and LDH activities was most likely caused by muscle injury because creatine kinase activity was concurrently increased. Compared with baseline values, bile acid concentration and y-glutamyl transferase activity were not affected by liver biopsy or crush injury. Plasma sorbitol dehydrogenase activity was the most specific indicator of liver injury in both groups. Histologic changes correlated poorly with biochemical results, possibly because the small area of hepatic parenchyma that was damaged did not affect enzyme values substantially.

Clinicopathologic findings in a dog with a retrobulbar meningioma.

An 11-year-old Fox Terrier dog was evaluated for a 10-month history of progressive exophthalmia and visual deficits in the right eye. Ophthalmologic examination revealed severe corneal fibrosis and pigmentation, which obscured examination of the anterior chamber of the right eye. There was decreased retropulsion of the right eye. Neurological examination revealed an absent menace response bilaterally. Pupillary light reflex was normal in the left eye. Due to the corneal pathology, pupillary light reflex was unable to be evaluated in the right eye. A retrobulbar mass with heterogeneous echotexture was identified using ultrasonography. Cytological evaluation of a fine-needle aspirate of the mass disclosed a neoplastic cell population consisting of round to polygonal cells with lightly basophilic to gray cytoplasm and round to ovoid nuclei having a coarse granular chromatin pattern. Magnetic resonance imaging disclosed a right-sided retrobulbar mass that extended through the optic canal and was contiguous with an extra-axial mass in the ventral right rostral and middle cranial fossae. The mass displayed homogenous and strong contrast enhancement. Following exenteration, histological examination of the retrobulbar mass was consistent with meningioma. Immunohistochemically, tumor cells stained positive for vimentin (cytoplasmic) and E-cadherin (membranous), and negative for S100, pancytokeratin, and cytokeratins AE1 and AE3.

Erythrophagocytic multiple myeloma in a cat.

A 7-year-old neutered male domestic shorthair cat was presented to the Veterinary Medical Teaching Hospital at the University of Georgia for further evaluation of a suspected osteolytic lesion of the left 10th rib. Results of a CBC and biochemistry profile revealed mild nonregenerative anemia, hyperproteinemia, hyperglobulinemia, and hypercalcemia. Serum protein electrophoresis was consistent with a monoclonal gammopathy. Marked proteinuria with an increased urine protein to creatinine ratio was found. Cytologic examination of the liver, spleen, and bone marrow revealed numerous plasma cells, many of which were erythrophagocytic. Within the bone marrow, the plasma cells contained phagocytosed metarubricytes in addition to phagocytosed erythrocytes. A diagnosis of erythrophagocytic multiple myeloma was made and treatment with prednisone and melphalan was begun. Four weeks after presentation, the cat was euthanized due to clinical deterioration. A complete necropsy was performed. The distal one-third of the left 10th rib was completely absent. Histologically, there was no evidence for osteolysis or neoplastic cells in the remaining portion of the rib. However, large sheets of plasma cells were found infiltrating the spleen and bone marrow. Moderate erythrophagocytosis by the plasma cells was observed in both organs. The plasma cells, including the erythrophagocytic cells, were positive for CD79alpha by immunohistochemical staining. Erythrophagocytosis by plasma cells as a cause of anemia is uncommon in people with multiple myeloma and is rare in animals. To our knowledge, this is the first report of erythrophagocytic plasma cells in a cat with multiple myeloma.

Mycoplasma haemolamae infection in a 4-day-old cria: support for in utero transmission by use of a polymerase chain reaction assay.

Blood smear examination in a 4-day-old alpaca revealed massive erythrocyte parasitism by Mycoplasma haemolamae. Blood collected from both the nonparasitemic dam and the cria were positive for M. haemolamae by polymerase chain reaction (PCR) analysis. These findings suggest in utero transmission of M. haemolamae in camelids, even when the dam is not parasitemic.

Cerebrospinal fluid from a 10-year-old dog with a single seizure episode.

A cerebrospinal fluid sample collected from the cerebellomedullary cistern of a 10-year-old Shetland Sheepdog with a recent history of seizures was submitted for fluid analysis and cytologic examination. Key findings included a total nucleated cell count of 520/microL (reference interval 0-5 cells/microL), with a predominance of mononuclear cells, a protein concentration of 51.8 mg/dL (reference interval 0-35 mg/dL), and a glucose concentration of 44.7 mg/dL (reference interval 52-105 mg/dL). There was marked atypia of the mononuclear cells, with abundant eosinophilic cytoplasm, marked anisocytosis and anisokaryosis, occasional binucleated cells, mitotic figures, and rare erythrophagia. The cytologic interpretation was marked, monocytoid-rich, mixed cell pleocytosis with cellular atypia worrisome for neoplasia. In addition to histiocytic neoplasia, differentials included granulomatous meningoencephalomyelitis, necrotizing meningoencephalitis, and granulomatous inflammation. The dog did not respond to anti-inflammatory and anticonvulsive therapy. At necropsy, a mass involving the meninges and subtending the neuropil of the right temporal lobe of the cerebrum was found. Histologically, the mass was composed of large, bizarre histiocytic cells with multinucleated forms and numerous mitotic figures. Using immunochemistry on cytologic and histologic samples, the pleomorphic histiocytic cells were positive for CD1c, CD11ad, CD45, lysozyme, and vimentin, and were negative for CD3, CD4, CD79a, CD90, and pancytokeratin. These findings supported a diagnosis of primary CNS malignant histiocytosis of dendritic antigen-presenting cell (CD1c+) origin. To our knowledge, this is only the third reported case of primary CNS histiocytic sarcoma in dogs, and the first to demonstrate strong immunochemical evidence for dendritic antigen-presenting cell origin.

Aerobic bacterial flora of the vagina and prepuce of California sea lions (Zalophus californianus) and investigation of associations with urogenital carcinoma.

To investigate the association between genital bacterial infection and urogenital carcinoma in California sea lions (Zalophus californianus), vaginal and preputial swabs for bacterial isolation were taken from 148 free-ranging and 51 stranded California sea lions including 16 animals with urogenital carcinoma. Cytological examination of vaginal or preputial smears showed a majority (65.5%, 57/87) of animals examined had mild or no inflammation. Aerobic bacteria were isolated from 116 (78.4%) wild sea lions and 100% of stranded animals. A total of 403 isolates were identified representing 51 unique bacterial species. The median number of isolates per animal increased with age in the wild group, but there was no difference in the number of isolates per animal between wild and stranded adults. The most common bacteria isolated from the wild sea lions were Psychrobacter phenylpyruvicus (39 isolates), non-hemolytic Streptococcus (35 isolates), Corynebacterium spp. (30 isolates), and Escherichia coli (20 isolates). More bacterial species were isolated from stranded animals than wild animals (33 versus 26) and there was significantly less growth of P. phenylpyruvicus, Corynebacterium spp., and Moraxella-like spp. in the stranded animals. Beta-hemolytic Streptococcus was the only bacterium significantly associated with urogenital carcinomas in California sea lions, but only in females.

Correlation between fine-needle aspiration cytopathology and histopathology of the lung in dogs and cats.

Medical records from 28 patients having fine-needle aspiration (FNA) cytopathology and histopathology of pulmonary lesions were reviewed. Clinical signs, thoracic radiographs, cytopathology, histopathology, and complications associated with FNA were evaluated. Correlation between cytopathological and histopathological diagnoses was determined. Cytopathological specimens were classified as neoplastic, inflammatory, or nondiagnostic. Histopathological diagnoses were categorized as neoplastic or inflammatory. No complications were observed following FNA. Diagnoses obtained by FNA cytopathology accurately reflected the diagnosis obtained on histopathological examination in 82% of cases. Fine-needle aspiration cytopathology of the lung is a useful and safe diagnostic tool in dogs and cats with pulmonary parenchymal lesions.

Evaluation of cystatin C as an endogenous marker of glomerular filtration rate in dogs.

Cystatin C is a cysteine protease inhibitor produced by all nucleated cells. It is freely filtered by the glomerulus and is unaffected by nonrenal factors such as inflammation and gender. Because of greater sensitivity and specificity, cystatin C has been proposed to replace creatinine as a marker of glomerular filtration rate (GFR) in humans. The aims of this study were to validate an automated assay in canine plasma and to evaluate the usefulness of cystatin C as a marker of GFR in dogs. Western blotting was used to demonstrate cross-reactivity of an anti-human cystatin C antibody. An immunoturbidimetric assay was used to detect cystatin C in 25 clinically healthy dogs and 25 dogs with renal failure. Mean cystatin C concentration in the healthy dogs and the dogs with renal failure was 1.08 +/- 0.16 mg/L and 4.37 +/- 1.79 mg/L respectively. Intra- and interassay variability was <5%. The assay was linear (r = .974) between 0.14 and 7.53 mg/L. Both cystatin C and creatinine concentrations were measured in banked, frozen serum from 20 remnant kidney model dogs and 10 volume-depleted dogs for which GFR measurements by exogenous creatinine clearance had been determined previously. In the remnant kidney model, cystatin C was better correlated with GFR than creatinine (r = .79 versus .54) but was less well correlated with GFR in volume-depleted dogs (r = .54 versus .95). GFR measurements were repeated in the remnant kidney model dogs 60 days after initial GFR measurements. At this time, cystatin C and creatinine concentrations correlated equally well with GFR (r = .891 versus .894, respectively). Cystatin C concentration is a reasonable alternative to creatinine for screening dogs with decreased GFR due to chronic renal failure.