Central nervous system lymphoma in 18 dogs (2001 to 2015).

OBJECTIVES: To investigate the outcome of dogs with central nervous system lymphoma. MATERIALS AND METHODS: A multi-center, retrospective, observational study was conducted by reviewing medical records of 18 cases of central nervous system lymphoma from seven institutions. RESULTS: Diagnosis of lymphoma was made through cerebrospinal fluid analysis, histopathology, flow cytometry of the cerebrospinal fluid, and cytology of cerebrospinal fluid, lymph node or spleen with correlated imaging. A total of 15 of 18 dogs received specific treatment other than prednisone. Three dogs underwent chemotherapy and radiation therapy after surgical decompression, five dogs underwent chemotherapy, two dogs underwent radiation therapy after surgical decompression, three dogs underwent chemotherapy after surgical decompression and two dogs underwent radiation therapy and chemotherapy. Only one dog received prednisone, and two dogs did not receive any treatment. Overall, the median survival time was 171 days (range 1 to 1942 days). CLINICAL SIGNIFICANCE: Dogs receiving any type of treatment for central nervous system lymphoma lived longer than cases described in previous historical reports. Further studies are needed to elucidate the importance of specific treatment modalities.

Effect of pre-cardiac and adult stages of Dirofilaria immitis in pulmonary disease of cats: CBC, bronchial lavage cytology, serology, radiographs, CT images, bronchial reactivity, and histopathology.

A controlled, blind study was conducted to define the initial inflammatory response and lung damage associated with the death of precardiac stages of Dirofilaria immitis in cats as compared to adult heartworm infections and normal cats. Three groups of six cats each were used: UU: uninfected untreated controls; PreS I: infected with 100 D. immitis L3 by subcutaneous injection and treated topically with selamectin 32 and 2 days pre-infection and once monthly for 8 months); IU: infected with 100 D. immitis L3 and left untreated. Peripheral blood, serum, bronchial lavage, and thoracic radiographic images were collected from all cats on Days 0, 70, 110, 168, and 240. CT images were acquired on Days 0, 110, and 240. Cats were euthanized, and necropsies were conducted on Day 240 to determine the presence of heartworms. Bronchial rings were collected for in vitro reactivity. Lung, heart, brain, kidney, and liver tissues were collected for histopathology. Results were compared for changes within each group. Pearson and Spearman correlations were performed for association between histologic, radiographic, serologic, hematologic and bronchoalveolar lavage (BAL) results. Infected cats treated with selamectin did not develop radiographically evident changes throughout the study, were heartworm antibody negative, and were free of adult heartworms and worm fragments at necropsy. Histologic lung scores and CT analysis were not significantly different between PreS I cats and UU controls. Subtle alveolar myofibrosis was noted in isolated areas of several PreS I cats and an eosinophilic BAL cytology was noted on Days 75 and 120. Bronchial ring reactivity was blunted in IU cats but was normal in PreS I and UU cats. The IU cats became antibody positive, and five cats developed adult heartworms. All cats with heartworms were antigen positive at one time point; but one cat was antibody positive, antigen negative, with viable adult females at necropsy. The CT revealed early involvement of all pulmonary arteries and a random pattern of parenchymal disease with severe lesions immediately adjacent to normal areas. Analysis of CT 3D reconstruction and Hounsfield units demonstrated lung disease consistent with restrictive pulmonary fibrosis with an interstitial infiltrate, absence of air trapping, and decrease in total lung volume in Group IU as compared to Groups UU and PreS I. The clinical implications of this study are that cats pretreated with selamectin 1 month before D. immitis L3 infection did not become serologically positive and did not develop pulmonary arterial hypertrophy and myofibrosis.

Nasal tumor with widespread cutaneous metastases in a Golden Retriever.

An intact, 8-year-old, male Golden Retriever dog was presented for evaluation of a nasal mass and approximately 30 firm, raised, variably ulcerated dermal and subcutaneous masses. Histopathology of both nasal and multiple skin masses revealed multiple nonencapsulated, infiltrative masses comprising clusters, anastomosing trabeculae, and packets of neoplastic, round to ovoid, hyperchromatic cells with marked nuclear molding. Surrounding the neoplastic cells was a marked stromal response in which many of the spindle-shaped cells expressed muscle-specific actin and had ultrastructural features consistent with myofibroblasts. A literature search indicates that this is the first report in a peer-reviewed journal of cutaneous metastasis of a nasal neuroendocrine tumor in any domestic animal species.

Multicentric cutaneous neuroendocrine (Merkel cell) carcinoma in a dog.

Multicentric cutaneous neuroendocrine (Merkel cell) carcinoma was diagnosed in a 5-year-old castrated male Keeshond dog with multiple firm nodular cutaneous masses. The neoplastic tissue locally effaced the periadnexal and deep dermis and consisted of densely cellular confluent clusters of round to polygonal cells supported by a delicate fibrovascular stroma. The cells were moderately immunoreactive with chromogranin A, synaptophysin, and cytokeratin. Ultrastructurally, the cells had characteristic membrane-bound dense-core neuroendocrine granules approximately 120 nm in diameter and randomly dispersed throughout the cytoplasm. Effacement of dermal structures and multicentric distribution suggested low-grade malignant phenotype. These findings contrast with the typical benign behavior of canine cutaneous neuroendocrine tumors.

Ocular metastasis of a vaccine-associated fibrosarcoma in a cat.

A 6-year-old, neutered male domestic shorthair cat was evaluated for a recurrent vaccine-associated fibrosarcoma. The cat had three excisions of the tumour prior to presentation and was referred for radiation therapy. Ten months following treatment with radiation therapy, the cat was presented again for a cloudy appearance to the eye. An exenteration was performed, and biopsy revealed fibrosarcoma. At the same time, two discrete pulmonary nodules were identified on thoracic radiographs. Two doses of doxorubicin (20 mg/m(2)) and cyclophosphamide (100 mg/m(2)) were administered intravenously 3 weeks apart. Despite treatment, the pulmonary nodule doubled in size. This case represents the first antemortem report of ocular metastasis of a vaccine-associated sarcoma and supports the highly aggressive nature of these tumours.

Radiation therapy in the treatment of canine and feline thymomas: a retrospective study (1985-1999).

A retrospective study was performed of 17 dogs and seven cats with various stages of thymoma treated with radiation alone or as an adjunctive therapy. Analysis revealed an overall response rate of 75% (15/20 evaluable cases). Partial (i.e., >50% reduction in tumor size) and complete (i.e., no detectable tumor) responses were included. Complete responses were rare (4/20). Three of five animals with stable disease (i.e., <50% change in tumor size) had improvements in clinical signs, despite lack of measurable response. A median survival time of 248 days (range, 93 to 1,657+ days) was achieved in dogs, and a median survival time of 720 days (range, 485 to 1,825+ days) was achieved in cats. Radiation therapy appears to be useful in the management of invasive thymomas in dogs and cats.

Use of dual energy x-ray absorptiometry for noninvasive body composition measurements in clinically normal dogs.

OBJECTIVE: To determine quantitative values for components of body composition in clinically normal dogs of various breeds by use of dual energy x-ray absorptiometry (DEXA) and validate the precision and accuracy of DEXA technology in dogs. ANIMALS: 103 clinically normal sexually intact adult dogs. PROCEDURE: In a cross-sectional study, Beagles, Pembroke Welsh Corgis, Golden Retrievers, Great Danes, Pointers, Rottweilers, and nonpurebred dogs received total body DEXA scans. For the validation portion of the study, the results of DEXA scans of 6 dogs were compared with values obtained by chemical analyses of tissues from euthanatized dogs to determine the accuracy of this modality in dogs. RESULTS: Results (coefficient of variation) of the precision tests ranged from 0.10% for lean tissue to 5.19% for fat tissue, whereas accuracy tests revealed a difference between percentage bone mineral content and ash values. Body composition differed by sex, such as higher lean tissue and bone mineral content in males within some breeds, and among breeds. Regardless of body size or weight, the percentage of body weight that was bone mineral ranged from 3 to 4.0% [corrected]. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this cross-sectional study provide valuable body composition data for clinically normal adult dogs, which may have research and clinical applications.

Oral treatment with a nutraceutical (Cosequin) for ameliorating signs of navicular syndrome in horses.

Fourteen horses with a progressive forelimb lameness of 3 to 12 months' duration, diagnosed as navicular syndrome, were selected from clinical cases admitted to Auburn University Equine Hospital for evaluation of the efficacy of an orally administered nutraceutical (Cosequin, Nutramax Laboratories, Inc., Edgewood, MD) for ameliorating clinical signs associated with naturally occurring navicular syndrome. Horses were randomly allocated to treatment with the nutraceutical or a placebo. Treatment was five scoops (16.5 g) of powder twice daily in the feed. The test group (n = 8) received a patented nutraceutical consisting of 9 g of FCHG49 (a highly purified glucosamine HCl), 3 g of TRH122 (a specific purified low-molecular-weight sodium chondroitin sulfate), and 600 mg of manganese ascorbate. The placebo group (n = 6) received an indistinguishable oral powder containing only excipients. Owners and the investigator were unaware of group assignments. The same investigator assessed lameness and overall clinical condition at enrollment and after 4 and 8 weeks of treatment. Lameness was assessed by an algofunctional lameness index, comprising a combined sum score of standing posture, hoof tester examination, and lameness scores at various levels of work. Overall clinical efficacy was rated on a visual analogue scale. Owners assessed lameness via a preassigned questionnaire, incorporating an algofunctional lameness index and overall clinical condition at weekly intervals. Radiographic examinations of the navicular bones were performed at enrollment and after 8 weeks of treatment. The median algofunctional lameness index and overall clinical condition scores assigned the investigator were significantly improved (P = .05) for horses treated with the nutraceutical compared with placebo-treated horses. The degree of improvement in algofunctional lameness index assigned by owners after 8 weeks was also significant (P = .045) between the treatment groups. Radiographic scores after treatment were not significantly different between the groups (P > .05).

Use of surgery and electron beam irradiation, with or without chemotherapy, for treatment of vaccine-associated sarcomas in cats: 78 cases (1996-2000).

OBJECTIVE: To evaluate responses of cats with vaccine-associated sarcomas to treatment with surgery and radiotherapy, with or without adjunctive chemotherapy. DESIGN: Retrospective study. ANIMALS: 76 cats (78 tumors). PROCEDURE: Medical records were reviewed. Factors potentially associated with survival time, time to recurrence, and time to development of metastases were evaluated. RESULTS: Following excision, electron beam radiation, and, in some cases, chemotherapy, 32 (41%) cats experienced recurrence, and 9 (12%) cats developed metastases. One- and 2-year survival rates were 86 and 44%, respectively. Median survival time from onset of disease was 730 days (range, 30 to 2,014 days). Median disease-free interval was 405 days (range, 30 to 925 days). Cats that underwent only 1 surgery prior to radiotherapy had a lower recurrence rate than did cats that underwent > 1 surgery and had a significantly longer disease-free interval. Survival time and disease-free interval decreased as time between surgery and the start of radiotherapy increased. Cats that developed metastases had significantly shorter survival times and disease-free intervals than did cats that did not develop metastases. Castrated male cats had a significantly shorter survival time than did spayed female cats. Cats with larger tumors prior to the first surgery had shorter survival times. Twenty-six cats received chemotherapy in addition to surgery and radiotherapy. Whether cats received chemotherapy was not associated with recurrence rate, metastasis rate, or survival time. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that excision followed by electron beam irradiation may be beneficial for treatment of cats with vaccine-associated sarcomas. Extent of excision prior to radiotherapy did not seem to be associated with recurrence rate.

Prevalence of feline heartworm infections among cats with respiratory and gastrointestinal signs: results of a multicenter study.

Although heartworm infection in cats was first described in 1921, the diagnosis of the infection remains elusive in many cases. This is due to nonspecific clinical signs of feline heartworm disease, typically low worm burdens, unique pathophysiology in the cat, and the limitations of currently available heartworm tests. Consequently, knowledge about this disease is still limited. An objective of this study was to survey the occurrence and clinical presentation of feline heartworm infection among cats presenting with clinical signs consistent with heartworm disease. Two-hundred fifteen cases were submitted from 15 private practices in Florida, South Carolina, Tennessee, and Texas. Cats entered in the study were at least 6 months of age and presented with one or more of the following clinical signs: respiratory signs, including tachypnea, dyspnea, or coughing; gastrointestinal signs, including a pattern of intermittent vomiting unrelated to eating; or sudden death of uncertain etiology, particularly associated with respiratory distress prior to death. Data collected included: history and indoor/ outdoor lifestyle; physical examination findings; thoracic radiography evaluations; Knott or DIFIL test results, DiroCHEK antigen test results, and antibody test results (Animal Diagnostics, Inc. and Heska Corporation); and CBC results. Recheck examinations were scheduled for any cat with positive heartworm serological test results and for cats with radiographic signs consistent with or suggestive of feline heartworm disease. Data from 215 cases were collected and analyzed: 94/215 (44%) tested antibody positive for one or both antibody tests that were performed; 18/94 (19%) of the antibody-positive cats were reported as living 100% indoors by their owners; (12%) of the antibody-positive cats spent less than or equal to 10% of their time outdoors. Eleven of 215 cats (5%) were DiroCHEK antigen positive on initial examination. One cat was both DiroCHEK and microfilariae positive, but negative for both antibody tests. Radiographs were obtained for 10 of these cats and 6/10 had radiographic signs consistent with or suggestive of feline heartworm infection. At necropsy, heartworms were found in one other cat from which blood was not obtained. Additionally, two cats that had positive radiographic signs of heartworm infection converted from antigen-negative to antigen-positive status at recheck examination for a total of 13/215 (6%) DiroCHEK antigen-positive cats. One case that was submitted after acute death was DiroCHEK antigen positive, but interestingly, had relatively low antibody levels for both antibody tests. Initial radiographs were available on 212 of the 215 cases. In 90/212 (42%) cases, initial thoracic radiographs showed signs consistent with or suggestive of heartworm disease. Follow-up radiographs showed varying progression with radiographic signs worsening, improving, or staying the same on individual cats. Feline heartworm disease should be among the primary differential diagnoses in cats with respiratory disease, vomiting, or acute death. Radiography, antibody testing, and antigen testing are all useful tools to aid in making the diagnosis. A confirmed diagnosis may require doing multiple tests and clinical reevaluation. Cats classified by their owners as indoor only cats were found to be heartworm infected, thus lifestyle of the cat cannot rule out the disease. Actual antibody levels (high or low) may not correspond to severity of disease.

Radiographic diagnosis of feline heartworm disease and correlation to other clinical criteria: results of a multicenter clinical case study.

Two-hundred fifteen cats with clinical signs consistent with feline heartworm disease (FHD) were entered into this clinical case study. In addition to physical examination, CBC, and heartworm antibody (Ab) and antigen (Ag) tests, thoracic radiographs were taken of 212 cats at initial examination. For cats that had a positive Ab or Ag test, or radiographic changes that could be associated with FHD, follow-up radiographs were taken at approximately 60 to 90 days after initial examination whenever possible. Each radiographic examination included VD, DV, and left lateral views, and each was read by the same board-certified radiologist who was blinded to heartworm serological results until after radiographic evaluation was completed. Criteria evaluated included heart size and shape, pulmonary artery enlargement, pulmonary parenchymal involvement, hyperinflation of lungs, tenting of the diaphragm, and pleural fluid accumulation. Summary interpretations and heartworm score were recorded. The heartworm score reflected the degree of suspicion of FHD based on radiographic signs: no radiographic signs of FHD; bronchointerstitial lung pattern only (consistent with but not specific for FHD); or pulmonary artery enlargement (with or without pulmonary or cardiac changes) mildly, moderately, or strongly indicative of FHD. Of 212 cats for which radiographs were taken at the initial examination, 38 (18%) had enlarged caudal lobar arteries indicative of FHD and 90 (42%) had bronchointerstitial pulmonary disease consistent with heartworms and/or enlarged caudal lobar arteries. Radiographic changes consistent with or indicative of FHD were evident in 9/22 cats (41%) presenting with gastrointestinal signs, 39/78 cats (50%) presenting with respiratory signs, and 41/80 cats (51%) presenting with both respiratory and gastrointestinal signs. Some cats presenting with only gastrointestinal signs had thoracic radiographic changes suggestive of FHD. Eleven cats tested DiroCHEK Ag positive, and radiographs were taken of 10. Of the 10 cats, 5 had radiographic changes indicative of FHD; one had changes consistent with FHD; and 4 cats showed no radiographic signs of FHD. Follow-up radiographs were taken of 6 of these 11 cats: 1/6 worsened in radiographic score, 3/6 improved in radiographic score, and 2/6 still demonstrated no radiographic signs of heartworm. Ninety-two cats tested Ab positive at initial examination, and radiographs were available for 91 of these cats. In 22/91 (24%), enlarged caudal lobar arteries indicated FHD. In 39/91 cats (43%) cats, radiographic signs consistent with or indicative of FHD were seen. Of the 38 cats that had radiographic signs indicative of FHD, 22 (58%) were Ab positive on one or both tests. Seven (32%) had positive DiroCHEK Ag tests at initial or recheck examination. At recheck examinations, 2 cats that initially had radiographic signs indicative of FHD converted from DiroCHEK Ag negative to positive, confirming their infection with at least 1 sexually mature female heartworm. While many affected cats show pulmonary arterial enlargement and/or a bronchointerstitial pattern typical of FHD, some cats with serologic evidence of heartworms do not demonstrate any thoracic radiographic changes. Conversely, some cats show radiographic signs suggesting heartworm disease when concurrent serology is negative. These discrepancies may be caused by time between infection and examination, by differences in individual cats' immune response to the presence of larval or adult stages of heartworm, or by aberrant migrations.

Survival in dogs with nasal adenocarcinoma: 64 cases (1981-1995).

Case records of 64 dogs with nasal adenocarcinoma were reviewed. The effects of age, gender, tumor stage, presence of metastatic lesions, and treatment method on survival time were examined. Surgery groups included rhinotomy (n = 9), transnasal curettage (n = 29), and no surgery (n = 26). Chemotherapy groups included fluorouracil-cyclophosphamide combination therapy (n = 15), mitoxantrone (n = 7), and no chemotherapy (n = 42). Fifty-three dogs received fractionated cobalt 60 radiation therapy. Surgical procedure, chemotherapy group, and stage of primary tumor were not significantly associated with survival time (P > .05). Dogs that received radiation therapy had a significantly longer median survival time (424 days) than dogs that did not (126 days)(P = .0001). The presence of either regional lymph node or pulmonary metastasis was associated with significantly shorter median survival time (109 days) when compared to dogs without metastases (393 days)(P = .0125). When only dogs that had received radiation therapy were considered, neither surgical treatment nor chemotherapy group was associated with significant changes in median survival time. An alternate staging system emphasizing the presence or absence of metastases is proposed.

Pharmacokinetics and tolerance of weekly OXYGENT CA infusions in the dog.

This study determined the OXYGENT CA (90% w/v perflubron emulsion, Alliance Pharmaceutical Corporation) dose necessary to achieve a 3-4% fluorocrit, and the tolerance of this dose administered once per week for four weeks to dogs. This study simulated OXYGENT CA use as a radiosensitizing agent. Six adult dogs were administered 6 ml/kg OXYGENT CA once per week for 4 weeks. Blood samples were collected following infusion, until fluorocrits were < or = 0.5%. One week after the fourth infusion, three dogs were necropsied. Liver biopsies were obtained from the remaining three dogs which were monitored 12 additional weeks. All dogs achieved fluorocrits > 3.0% (3.5-5.1%) with the 6 ml/kg dose. A 3 ml/kg dose did not provide a fluorocrit > 3.0%. Serum bilirubin concentrations were elevated at 24-hour sampling times and declined within 72 hours. Elevations in ALT, SAP, and bile acids were noted. Splenic and hepatic microvasculature fibrosis occurred in the long-term study dogs. Thrombocytopenia occurred in 5/6 dogs, necessitating exclusions of one dog from 2 infusions. However, 3/5 thrombocytopenic dogs had titers for Ehrlichia sp., which elicits thrombocytopenia. Therefore, we cannot conclude the effect of OXYGENT CA on platelets.

Nuclear imaging.

Nuclear imaging (scintigraphy) is a noninvasive diagnostic procedure that can provide complementary information to that obtained by radiography, CT, MRI, or ultrasonography. Nuclear imaging is based on physiologic distribution of radiopharmaceutical compounds within the body so that it allows assessment of organ functions. When digital image processing is employed, nuclear imaging can allow quantitative assessment of organ function. This article provides an overview of common nuclear imaging procedures used in veterinary medicine.

Metastatic thyroid solid-follicular carcinoma in the cervical portion of the spine of a dog.

A metastatic thyroid solid-follicular carcinoma in the cervical portion of the spine was responsible for severe tetraparesis in a dog. Myelography revealed an extradural compressive lesion dorsal and to the right of the midline of C3. Histologic examination was used to diagnose the mass as a solid-follicular thyroid carcinoma. The primary tumor was not evident on cervical palpation or radiography. A dorsal laminectomy centered over C3 was performed, and all visible tumor was removed from the spine. The owner declined any further treatment for the dog.

Ferromagnetic thermoseeds: suitable for an afterloading interstitial implant.

Previous studies have shown implantable ferromagnetic thermoseeds to be a promising hyperthermia method. However, migration from the implant site and chemical toxicity caused by corrosion of the thermoseed alloy have proven to be potential hazards. These problems could be overcome by placing the thermoseeds into removable catheters similar to those used for afterloading interstitial brachytherapy. As an additional merit, the method would allow convenient combination of heat and radiation therapy. To test the clinical performance of this method, we compared temperature distributions and biologic effects in canine muscle and transmissible venereal tumors for bare thermoseeds and thermoseeds contained within catheters. We found no significant difference in the heating patterns and similar tissue changes when all implants were removed immediately after heating. More severe tissue changes were present around bare thermoseeds that were retained. This suggests that catheters provide a safe and reliable method for thermoseed hyperthermia which would allow convenient combination with interstitial radiation.

Biologic characterization of canine melanoma cell lines.

Eight canine melanoma cell lines were established from tissues from 6 dogs with spontaneous primary or metastatic melanomas. Cell lines were characterized for morphologic features and growth patterns on plastic, pigmentation, ultrastructure, cloning efficiency in soft agar, and tumorigenicity in nude mice. Biologic properties of cell lines were distinct and preserved during 40 to 120 passages in vitro. All cell lines were clonogenic and tumorigenic.

Technique for percutaneous pulmonary arterial catheterization in conscious dogs.

A technique was developed to allow percutaneous placement and exchange of pulmonary arterial catheters in conscious dogs. Seven dogs were catheterized weekly for 5 weeks, using a 10-gauge over-the-needle cannula. A No. 7 F flow-directed catheter was passed through the cannula to measure right heart and pulmonary arterial pressures and to calculate cardiac output. The flow-directed catheter was removed and replaced with an arteriographic catheter, and a pulmonary arteriogram was performed. Placement in alternate jugular or saphenous veins each week resulted in successful catheterizations in all dogs evaluated.