Progressive angiomatosis, resembling human skeletal-extraskeletal angiomatosis, arising in multiple digits in two dogs.

Two dogs presented with progressive, expansile and invasive lesions on a hind paw. Case 1, a 10-year-old female Shetland sheepdog had diffusive and aggressive-looking lesions on the middle digits of the left hind paw. Radiographic examination showed invasion into and destruction of the underlying bone. A malignant tumour was suspected initially; however, histological features of atypical vascular proliferations without mitotic activity were consistent with progressive angiomatosis. Case 2, an 11-year-old female English springer spaniel presented with similar lesions in the same toes, also involving bone. Progressive angiomatosis was suspected clinically, as tumour cells were not detected by cytology and screening did not detect metastatic disease. Histopathology confirmed the diagnosis. Progressive angiomatosis is an uncommon non-malignant condition which should be considered as a differential diagnosis for radiographically lytic digital lesions.

Clinical findings and outcome following medical treatment in dogs with idiopathic renal haematuria: 41 cases (2001-2018).

OBJECTIVES: To characterise and document the progression of idiopathic renal haematuria in a large cohort of medically managed UK dogs. MATERIALS AND METHODS: Retrospective study of 41 client-owned dogs with confirmed (n=14), or suspected (n=27) idiopathic renal haematuria from 4 UK-based referral centres. Clinical findings and outcomes of dogs (2001 to 2018) were determined from the review of medical records and telephone follow-up. RESULTS: Median survival time from diagnosis was long [1482 (152 to 1825) days] irrespective of treatment and clinical response. Only 1 case was euthanased due to idiopathic renal haematuria, and anaemia or azotaemia occurred infrequently. In total, 25 dogs received angiotensin-converting enzyme-inhibitor or angiotensin receptor blocker therapy, of which 23 received benazepril [0.44 (0.19 to 0.82) mg/kg/24 hours], two received enalapril (0.40 and 0.78 mg/kg/24 hours) and one received telmisartan (1 mg/kg/24 hours). In cases with follow-up urinalyses, complete resolution of haematuria was documented in eight of 19 (42%) dogs following angiotensin-converting enzyme-inhibitor/angiotensin receptor blocker treatment, with partial improvement in five of 19 (26%) and no improvement in six of 19 (31%). Conversely, of the two untreated dogs where outcome was available, one had partial improvement and the other had no improvement. CLINICAL SIGNIFICANCE: In this study, idiopathic renal haematuria was associated with a good prognosis and low complication rate. Resolution or improvement in haematuria occurred in both angiotensin-converting enzyme-inhibitor/angiotensin receptor blocker-treated and untreated dogs, indicating that further studies are required to evaluate the effectiveness and safety of these interventions.

Diagnostic value of MRI in dogs with inflammatory nasal disease.

OBJECTIVES: To determine the value of low-field magnetic resonance imaging in differentiating sino-nasal aspergillosis from lymphoplasmacytic rhinitis in dogs. METHODS: A retrospective study of 41 dogs (25 with lymphoplasmacytic rhinitis and 16 with sino-nasal aspergillosis) that underwent magnetic resonance imaging scan of the nasal cavity was conducted. On magnetic resonance imaging, turbinate destruction was classified as mild, moderate or severe. The cribriform plate and vomer destruction were classified as present or absent. The intensity of fluid accumulation and turbinates was classified on T1-weighted and T2-weighted images as hypointense, hyperintense and isointense based on the brightest area on the same slice. RESULTS: Turbinate destruction was significantly (P=0·005) associated with sino-nasal aspergillosis. On T1-weighted images, sino-nasal aspergillosis was associated with turbinate hyperintensity, while lymphoplasmacytic rhinitis was significantly (P=0·007) associated with hypointensity. On T2-weighted images, this feature was shown not to be relevant. CLINICAL SIGNIFICANCE: This study has demonstrated that turbinate destruction is the most reliable feature to differentiate sino-nasal aspergillosis from lymphoplasmacytic rhinitis and that T1-weighted image was the most useful sequence.

Diagnostic accuracy of three biopsy techniques in 117 dogs with intra-nasal neoplasia.

OBJECTIVES: To determine if nasal biopsies taken at rhinoscopy are more accurate for diagnosing neoplasia than biopsies taken blindly or using advanced imaging for guidance. METHODS: A retrospective study of 117 dogs with nasal mass lesions that were divided into three groups according to the method of nasal biopsy collection; advanced imaging-guided, rhinoscopy-guided and blind biopsy. Signalment, imaging and rhinoscopic findings, and histopathological diagnosis were compared between groups. The proportion of first attempt biopsies confirming neoplasia were determined for each group. RESULTS: There were no statistically significant differences in the proportion of biopsies that confirmed neoplasia obtained via advanced imaging-guided, rhinoscopy-guided or blind biopsy techniques. CLINICAL SIGNIFICANCE: In dogs with a high index of suspicion of nasal neoplasia, blind biopsy may be as diagnostic as rhinoscopy-guided biopsy. Repeated biopsies are frequently required for definitive diagnosis.

Exclusion of a brain lesion: is intravenous contrast administration required after normal precontrast magnetic resonance imaging?

BACKGROUND: No evidence-based guidelines are available for the administration of gadolinium-based contrast media to veterinary patients. OBJECTIVE: To investigate whether administration of intravenous (IV) contrast media alters the likelihood of identifying a brain lesion in dogs and cats. ANIMALS: Four hundred and eighty-seven client-owned animals referred for investigation of intracranial disease. METHODS: Two reviewers retrospectively analyzed precontrast transverse and sagittal T1-weighted (T1W), T2-weighted, and fluid-attenuated inversion recovery low-field MRI sequences from each patient for the presence of a clinically relevant brain lesion. All sequences subsequently were reviewed in the same manner with additional access to postcontrast T1W images. RESULTS: Of the 487 precontrast MRI studies, 312 were judged to be normal by 1 or both reviewers. Of these 312 studies, a previously undetected lesion was identified in only 6 cases (1.9%) based on changes observed on postcontrast sequences. Final diagnoses included meningoencephalitis of unknown origin (n = 1), feline infectious peritonitis (n = 1), and neoplasia (n = 2). All 4 of these cases had persistent neurological deficits suggestive of an underlying brain lesion. Contrast enhancement observed in the 2 other cases was considered falsely positive based on the results of further investigations. CONCLUSIONS AND CLINICAL IMPORTANCE: In patients with normal neurological examination and normal precontrast MRI, the subsequent administration of IV gadolinium-based contrast media is highly unlikely to disclose a previously unidentified lesion, calling into question the routine administration of contrast media to these patients. However, administration still should be considered in animals with persistent neurological deficits suggestive of an underlying inflammatory or neoplastic brain lesion.

Loeffler's endocarditis and bicavity eosinophilic effusions in a dog with visceral mast cell tumour and hypereosinophilia.

A 9-year-old crossbred dog was presented with a 2-week history of diarrhoea and tachypnoea. Marked circulating eosinophilia was identified. Pleural and abdominal effusions were detected by radiography and ultrasonography and cytological examination of these fluids revealed a predominance of eosinophils. Splenic and hepatic cytology revealed mast cell neoplasia, which was confirmed as visceral mast cell tumour on post-mortem examination. Histological changes of myocardial inflammation, necrosis and fibrosis were found. These findings are consistent with Loeffler's endocarditis.

Hypovitaminosis D in dogs with inflammatory bowel disease and hypoalbuminaemia.

OBJECTIVES: To compare serum vitamin D metabolites and plasma parathyroid hormone concentrations in dogs with inflammatory bowel disease and normal albumin concentration, dogs with inflammatory bowel disease and hypoalbuminaemia, healthy dogs and hospitalised ill dogs with non-gastrointestinal illness. METHODS: Serum 25 hydroxyvitamin D and 1,25 dihydroxyvitamin D concentrations were measured in 36 healthy dogs, 49 hospitalised ill dogs with non-gastrointestinal illnesses, 21 dogs with inflammatory bowel disease and normoalbuminaemia and 12 dogs with inflammatory bowel disease and hypoalbuminaemia. Plasma parathyroid hormone and ionised calcium concentrations were measured in a subset of these dogs. RESULTS: Concentrations of serum 25 hydroxyvitamin D were lower in hypoalbuminaemic dogs with inflammatory bowel disease than in the healthy dogs (P<0·001), hospitalised ill dogs (P<0·001) and normoalbuminaemic dogs with inflammatory bowel disease (P<0·001). Dogs with inflammatory bowel disease and hypoalbuminaemia had a higher plasma concentration of parathyroid hormone (P<0·01) and lower plasma concentration of ionised calcium (P<0·001) than hospitalised ill dogs. Dogs with inflammatory bowel disease had a positive correlation between serum 25 hydroxyvitamin D concentrations and serum albumin (P<0·0001), serum calcium (P<0·0001) and plasma ionised calcium (P<0·0005) concentrations. CLINICAL SIGNIFICANCE: Dogs with inflammatory bowel disease and hypoalbuminaemia frequently have ionised hypocalcaemia, high parathyroid hormone and low serum 25 hydroxyvitamin D concentrations. Further studies are indicated to establish the pathogenesis of this disease complication as well as therapeutic strategies to reverse this state.

Characterization of chronic pancreatitis in English Cocker Spaniels.

BACKGROUND: Chronic pancreatitis (CP) is common in dogs. The cause is unknown. In humans, different causes of pancreatitis have histologically distinct appearances. The histopathologic lesions in English Cocker Spaniels (ECS) with CP were noted to be histologically different than those of other breeds with CP. HYPOTHESIS: CP in ECS is distinct from CP in other breeds and is characterized by a duct destruction similar to what is observed in autoimmune CP of humans. ANIMALS: Eight ECS and 9 other breeds with histologically confirmed CP recruited over an 8-year period and 50 postmortem control dogs with CP. METHODS: Clinical, clinicopathological, and ultrasonographic findings were recorded. Histological sections were compared with a normal dog and 59 dogs of other breeds with CP. Immunohistochemistry using anti-CD3, anti-CD79a, and anti-cytokeratin antibodies was used to evaluate distribution and type of lymphocytic inflammation and appearance of pancreatic ducts. RESULTS: Four male and 4 female ECS presented at a mean age of 7.2 years. Clinical signs were similar in ECS and other breeds. The pancreas was enlarged and hypoechoic in 4 ECS and 2 controls. Histopathology was characterized by interlobular and periductular fibrosis and inflammation in ECS compared with intralobular disease in most other breeds. Immunohistochemistry identified prominent anti-CD3(+) lymphocytic infiltrates around venules and ducts and a marked absence of interlobular ducts in ECS compared with mixed T-cell infiltration and ductular hyperplasia in most other breeds with CP. CONCLUSIONS AND CLINICAL IMPORTANCE: CP in ECS is distinct from CP in other breeds and is notably duct destructive.

A comparison of factors that influence survival in dogs with adrenal-dependent hyperadrenocorticism treated with mitotane or trilostane.

BACKGROUND: Trilostane is a recognized treatment for canine pituitary-dependent hyperadrenocorticism (PDH); however, its efficacy in dogs with adrenal-dependent hyperadrenocorticism (ADH) is unknown. OBJECTIVES: To examine factors that might influence survival in the medical management of ADH, with particular emphasis on treatment selection. ANIMALS: Thirty-seven animals referred to 4 centers over a period of 12 years that had been diagnosed with ADH and treated with either trilostane (22/37), mitotane (13/37), or both (2/37). METHODS: Retrospective analysis of clinical records. RESULTS: There was no statistically significant difference between the survival times of 13 dogs treated only with mitotane when compared with 22 dogs treated only with trilostane. The median survival time for animals treated with trilostane was 353 days (95% confidence interval [CI] 95-528 days), whereas it was 102 days (95% CI 43-277 days) for mitotane. Metastatic disease was detected in 8 of 37 dogs. There was a significantly lower probability of survival for dogs with metastatic disease when compared with those without metastatic disease (P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: The choice of medical treatment for ADH may not have a major effect on survival times. However, the presence of metastatic disease considerably decreases survival time regardless of the choice of medical treatment.

Prevalence of hepatic lesions at post-mortem examination in dogs and association with pancreatitis.

OBJECTIVES: To assess the prevalence of canine chronic hepatitis (CH) and other liver diseases in first opinion practice and identify associations with concurrent chronic pancreatitis (CP). METHODS: One large section of left lateral lobe of liver was taken from 200 unselected canine post-mortem examinations from first opinion practices. Histological changes were categorised based on WSAVA criteria. Prevalence of CH and other liver diseases were calculated. Relative risks (RR) for liver histopathology in association with CP and for CH in different breeds were also calculated. RESULTS: The prevalence of CH was 12%. Some breeds had an increased RR of CH, although sample sizes were small. Dogs with CP had an increased RR of reactive hepatitis but no significant association with the other liver diseases. CLINICAL SIGNIFICANCE: CH is common in the first opinion dog population but less common than CP. CP was significantly associated with reactive hepatitis but not CH. Possible breed associations mirrored another recent UK study. Some dogs with CP may be erroneously diagnosed clinically as having CH on the basis of increased serum liver enzymes because of concurrent reactive hepatitis if the diagnosis is not confirmed histologically.

Observational study of 14 cases of chronic pancreatitis in dogs.

This study reports the clinical, clinicopathological and ultrasonographic findings from dogs with chronic pancreatitis (CP). Fourteen dogs with clinical signs consistent with CP and histological confirmation of the disease were evaluated. Abdominal ultrasound and clinical pathology results were recorded. Sensitivities of pancreatic enzymes for diagnosis of CP were calculated with two different cut-off values. The mean age of affected dogs was 9.1 years. Spaniels were the most common breed with CP, representing seven of the 14 dogs in this study. CP was histologically severe in nine cases. Most dogs showed chronic low-grade gastrointestinal signs and abdominal pain. Five dogs had exocrine pancreatic insufficiency and five dogs had diabetes mellitus. The sensitivity of elevated trypsin-like immunoreactivity for CP was 17 per cent. The sensitivities of canine pancreatic lipase immunoreactivity, lipase and amylase for CP were 44 to 67 per cent or 14 to 28 per cent depending on the cut-off value used. Cholesterol was elevated in 58 per cent of samples. Liver enzymes were often elevated. The pancreas appeared abnormal on 56 per cent of ultrasound examinations. Ten dogs had died by the end of the study period; only one case was due to CP.

Prognostic significance of specific magnetic resonance imaging features in canine nasal tumours treated by radiotherapy.

OBJECTIVES: To investigate the prognostic significance of the magnetic resonance (MR) findings of meningeal hyperintensity of the olfactory bulbs and tumour extension into the caudal nasal recess (CNR) in dogs with nasal tumours treated by radiotherapy. METHODS: MR images of 41 dogs with nasal tumours treated with radiotherapy were reviewed. The occurrence of neurological signs and survival of patients with and without meningeal hyperintensity of the olfactory bulbs and tumour extension into the CNR were analysed together with possible confounding factors including intracranial extension and patient age. RESULTS: There was no significant association between the presence of meningeal hyperintensity or CNR involvement and the occurrence of neurological signs. Although there was a tendency towards shorter survival in dogs with tumour extension into the CNR, multivariable analysis showed no significant difference in survival between dogs with/without CNR involvement, meningeal hyperintensity or intracranial tumour extension (P=0.12, 0.50 and 0.57, respectively). CLINICAL SIGNIFICANCE: In dogs with nasal tumours treated with radiotherapy, tumour extension into the cranium is not necessarily associated with shorter survival in patients without neurological signs at time of diagnosis. Although a definite influence of CNR involvement on case outcome could not be demonstrated, studies with a larger population are warranted.

Calcium metabolism in eight dogs with hypoadrenocorticism.

Hypoadrenocorticism is a well-described endocrinopathy in dogs that results from deficient production and secretion of glucocorticoids and/or mineralocorticoids. Although hyperkalaemia, hyponatraemia and hypochloraemia are the most common electrolyte disturbances, hypercalcaemia also occurs in approximately 30 per cent of cases. The pathogenesis of hypercalcaemia in dogs with hypoadrenocorticism is unknown. This case series reports ionised calcium, parathyroid hormone, parathyroid hormone-related protein and vitamin D metabolite concentrations that were measured in eight dogs with concurrent hypercalcaemia and hypoadrenocorticism. Ionised calcium was increased in five of seven dogs with hypercalcaemia associated with hypoadrenocorticism. Parathyroid hormone, parathyroid hormone-related protein and 1,25 dihydroxyvitamin D concentrations were within their reference ranges in seven of eight dogs, six of seven cases and six of seven dogs, respectively. This case series highlights that hypercalcaemia associated with hypoadrenocorticism is rarely associated with increases in plasma parathyroid hormone, parathyroid hormone-related protein or serum 1,25 dihydroxyvitamin D concentrations.

The cardiac biomarker NT-proBNP is increased in dogs with azotemia.

BACKGROUND: Amino-terminal probrain natriuretic peptide (NT-proBNP) has been proposed as a useful biomarker for heart disease in dogs. In humans, decreased glomerular filtration rate (GFR) increases NT-proBNP. OBJECTIVE: To investigate whether decreased GFR as indicated by plasma creatinine concentration is associated with increased NT-proBNP in dogs without heart disease. ANIMALS: Four groups of dogs: healthy (n= 39), azotemic (n= 36), heart disease (n= 37), and congestive heart failure (CHF) (n= 7) presented to 2 teaching hospitals. METHODS: Prospective observational cohort study. Plasma creatinine concentration and NT-proBNP were measured in every dog. Nonparametric tests were used to compare the differences among groups. The median and actual results for each group were compared with the manufacturer's recommended and previously published suggestions for cut-off values for diagnosis of heart disease. RESULTS: Median (range) plasma creatinine concentration was 1.47 (1.06-1.70), 4.36 (1.74-15.6), 1.22 (0.69-1.91), and 1.45 (0.63-1.64) mg/dL and median (range) NT-proBNP was 118 (2-673), 556 (37-1,819), 929 (212-5,658), and 3,144 (432-5,500) pmol/L for the healthy, azotemic, heart disease, and CHF groups, respectively. Pair-wise comparison indicated a significant difference among all groups for NT-proBNP (P< or = .049). Plasma creatinine concentration was significantly higher in the azotemic group compared with other groups (P < .001) but there was no significant among other groups. Application of 3 recommended cut-off values led to misclassification of dogs with azotemia as having heart disease. CONCLUSIONS: Azotemia results in NT-proBNP being increased to concentrations reported as diagnostic of heart disease or heart failure in dogs. Care should be employed when interpreting the results of NT-proBNP in patients with known or possible increased plasma creatinine concentration.

Haemophilia A (factor VIII deficiency) in a litter of Weimaraners.

Inherited coagulopathies are reported in a number of dog breeds. However, to date, there is no report of Weimaraners suffering factor VIII deficiency (haemophilia A). We report the discovery of haemophilia A in both males from a single litter of Weimaraners. Haemophilia A in human beings often results from a de novo stochastic mutation. We found no evidence using currently available screening tests of haemophilia A in relatives as far back as three generations making a stochastic mutation possible in this litter.

Exogenous insulin treatment after hypofractionated radiotherapy in cats with diabetes mellitus and acromegaly.

BACKGROUND: The optimal treatment for feline acromegaly has yet to be established. Surgical and medical therapies are minimally effective although radiotherapy might have greater efficacy. The purpose of this study was to review the response and outcome of cats with acromegaly and insulin-resistant diabetes mellitus (DM) to radiotherapy. HYPOTHESES: That radiotherapy improves glycemic control in cats with acromegaly and that improved glycemic control is due to remission of clinical acromegaly; demonstrated by a fall in serum insulin-like growth factor-1 (IGF-1) concentrations. ANIMALS: Fourteen cats with naturally occurring acromegaly. METHODS: Retrospective case review; records of all cats treated for acromegaly with radiotherapy were reviewed from 1997 to 2008. Cats were selected on the basis of compatible clinical signs, laboratory features, and diagnostic imaging findings. Fourteen cats received radiotherapy, delivered in 10 fractions, 3 times a week to a total dose of 3,700 cGy. RESULTS: Thirteen of 14 cats had improved diabetic control after radiotherapy. These improvements were sustained for up to 60 months. DM progressed in 2 cats and 1 did not respond. Seven cats responded before the final treatment. Ten cats were euthanized, 1 as a consequence of radiotherapy. In 8 cats in which IGF-1 was measured after treatment, changes in its concentration did not reflect the clinical improvement in glycemic control. CONCLUSIONS AND CLINICAL IMPORTANCE: Radiotherapy represents an effective treatment for cats with insulin-resistant DM resulting from acromegaly. IGF-1 concentration after treatment does not provide a suitable method by which remission from either acromegaly or insulin-resistant DM may be assessed.

Anti-insulin antibodies in diabetic dogs before and after treatment with different insulin preparations.

BACKGROUND: Anti-insulin antibodies (AIA) occur in diabetic dogs after insulin therapy, although their clinical significance is unclear. HYPOTHESIS: Treatment of diabetic dogs with heterologous insulin is more likely to stimulate production of AIA than is treatment with homologous insulin. ANIMALS: Diabetic dogs sampled before insulin therapy (n = 40), diabetic dogs sampled following treatment with porcine (homologous) insulin (n = 100), bovine (heterologous) lente insulin (n = 100), or bovine protamine zinc (PZI) insulin (n = 20), and nondiabetic control dogs (n = 120). METHODS: Prospective observational study. Sera were analyzed by ELISA for antibodies against porcine insulin, bovine insulin, insulin A, B, or C peptides, and control antigens; canine distemper virus (CDV) and canine thyroglobulin (TG). Canine isotype-specific antibodies were used to determine total and anti-insulin IgG1 : IgG2 ratios. RESULTS: There was no difference in CDV or TG reactivity among the groups. AIA were detected in 5 of 40 newly diagnosed (untreated) diabetic dogs. There was no significant difference in AIA (ELISA optical density reactivity) comparing control and porcine insulin-treated diabetic dogs (P > .05). Anti-insulin reactivity was most prevalent in bovine PZI insulin-treated dogs (90%; P < .01), and bovine lente insulin-treated dogs (56%; P < .01). AIA induced by treatment were enriched for the IgG1 isotype. CONCLUSIONS AND CLINICAL IMPORTANCE: This study indicates that bovine insulin is more immunogenic than porcine insulin when used for treatment of diabetic dogs.

Autoantibodies to GAD65 and IA-2 in canine diabetes mellitus.

Diabetes mellitus in dogs shares many characteristics with the human type 1 disease and virtually all diabetic dogs require insulin therapy to control hyperglycaemia. Insulin deficiency is suspected to result from immune-mediated destruction of pancreatic beta cells in some cases. Human patients suffering from Type 1A (immune-mediated) diabetes or latent autoimmune diabetes of the adult (LADA) demonstrate circulating autoantibodies against the 65kDa isoform of glutamic acid decarboxylase (GAD65) and/or insulinoma antigen-2 (IA-2). The aims of the current study were to develop radio-immunoassays to detect serum antibodies against recombinant canine GAD65 and IA-2 and to identify diabetic dogs showing serological evidence of autoreactivity to these pancreatic beta cell antigens. Canine GAD65 and the 3' end of IA-2 (coding for amino acids 771-979 of the intracellular domain) were amplified by PCR from cDNA prepared from canine insulinoma tissue and cloned into the pCRII vector. The canine sequences were later confirmed by identifying GAD2 and PTPRN genes from the dog genome assembly. Recombinant (35)S-methionine-radiolabelled canine GAD65 and IA-2 (771-979) proteins were used in radio-immunoprecipitation assays to screen sera from 30 newly diagnosed diabetic dogs and 30 control dogs. Four of 30 canine diabetic patients had significant GAD65 autoreactivity (p<0.01) compared to controls and 3 dogs were positive for autoantibodies to IA-2 (771-979). Two diabetic dogs showed dual autoantigen reactivity. These preliminary data indicate that serological reactivity to GAD65 and IA-2 is present in a proportion of diabetic dogs and suggests that, in some cases, canine diabetes is associated with an autoimmune response to these antigens.

Retrospective review of 50 canine nasal tumours evaluated by low-field magnetic resonance imaging.

OBJECTIVES: Low-field magnetic resonance imaging machines are being used more often in veterinary practice for the investigation of sinonasal disease. The aim of this retrospective study was to describe and characterise the low-field magnetic resonance imaging features of nasal tumours in dogs. METHODS: The Queen's Veterinary School Hospital magnetic resonance imaging database (2001-2005) was searched for dogs with a magnetic resonance imaging diagnosis of a nasal tumour. Fifty cases with histological diagnosis of nasal tumour were found. The appearance and extent of the nasal tumour as well as the involvement of adjacent anatomic structures were examined against a checklist. RESULTS: The most common magnetic resonance imaging findings were as follows. (1) Soft tissue mass replacing the destroyed nasal conchae and/or ethmoturbinates (98 per cent of cases). (2) Nasal septum destruction (68 per cent of cases). (3) Retained secretions with or without mass caudally in frontal sinuses (62 per cent of cases). (4) Nasal/frontal bone destruction (52 per cent of cases). Low-field magnetic resonance imaging allowed differentiation of tumour tissue from retained secretions or necrotic tissue. Magnetic resonance imaging was invaluable in assessing the extension of the tumour into the maxillary recesses, caudal recesses, nasopharynx, adjacent bones and cranial cavity. The tumour often extended caudally into the frontal sinuses, nasopharynx and perhaps most importantly into the caudal recesses. Tumour extension into the cranial cavity was not common (16 per cent), and only three of these cases showed neurological signs. However, 54 per cent of cases showed focal meningeal (dural) hyperintensity, although the significance of this is unclear. A significant difference (P<0.05) in tumour signal intensity between the sarcomas and carcinomas was found. CLINICAL SIGNIFICANCE: The use of a low-field magnetic resonance imaging technique is excellent for the diagnosis and determination of extent of sinonasal tumours.

Histopathologic, immunohistochemical, and cytologic analysis of feline myeloma-related disorders: further evidence for primary extramedullary development in the cat.

Feline myeloma-related disorders (MRD) are rare neoplasms of plasma cells. The multistep transformation model of myeloma in humans is based on the premise that plasma cells undergo neoplastic transformation primarily within the intramedullary compartment and that over time they become poorly differentiated and metastasize to extramedullary locations. Historically, diagnostic criteria used for human multiple myeloma have been applied to the cat, with the assumption that feline MRD commonly arises in the intramedullary compartment. Our objectives were to describe the features of feline MRD confirmed by cytology, histopathology, histochemistry, and immunohistochemistry and to categorize these tumors. A priori hypotheses were 1) tumor category predicts survival and 2) cats with well-differentiated tumors commonly have extramedullary involvement in contrast to human myeloma patients. This multicenter, retrospective study identified 26 MRD cases. There was good agreement between histopathologic and cytologic tumor categorization. Histochemistry and immunohistochemistry were shown to be valuable adjunct tests in the diagnosis of MRD. Cats with well-differentiated tumors had increased median survival relative to those with poorly differentiated tumors (254 versus 14 days). We have reported that marked extramedullary involvement at initial clinical presentation is significantly more common in the cat than in human MRD patients. In this study, we demonstrate that cats with well-differentiated tumors more commonly have extramedullary involvement than human myeloma patients with well-differentiated tumors (90% versus 20%, P < 0.0002). These results contrast strongly with the human myeloma model of primary intramedullary neoplastic transformation and suggest that primary extramedullary neoplastic transformation may be more common in feline MRD.