A randomised controlled comparison of aspiration and non-aspiration fine-needle techniques for obtaining ultrasound-guided cytological samples from canine livers.

Ultrasound-guided fine-needle sampling to obtain cytological samples is a well-established technique. However, the application of suction during sampling is controversial. Evidence from the human literature and one previous veterinary study suggest that non-aspiration may be superior for a number of organs. This prospective study compared the quality and diagnostic value of cytological samples from canine livers obtained by fine-needle aspiration (FNA) and non-aspiration (FN-NA) techniques. A total of 119 dogs that required ultrasound-guided FNA of the liver as part of their clinical investigation were recruited and randomly assigned to either FNA (n=54) or FN-NA (n=65) sampling groups. Specimens were reviewed by external cytopathologists masked to the technique used. Cytological reports were reviewed for their overall diagnostic value, cellularity, cell preservation and haemodilution. Overall, 88.2% (95% confidence intervals [CI], 82.4-94.0) of samples were diagnostic. There was a significant difference, as demonstrated by Chi-squared statistical analysis, in the prevalence of diagnostic samples between the FNA (81.5%; 95% CI, 71.1-91.8) and FN-NA groups (93.9%; 95% CI, 88.0-99.7; P=0.037). Non-diagnostic samples were significantly associated with lower cellularity, poorer cell preservation and more severe haemodilution (P<0.001 for each). However, there were no significant differences in the frequency of these specific variables between the FNA and FN-NA groups. In this study, fine-needle non-aspiration was superior to an aspiration technique for sampling the canine liver, as it resulted in higher rates of diagnostic cytology samples, with greater cellularity, less haemodilution and better cytological preservation.

Use of a rotary battery-powered device for the collection of bone marrow in dogs and cats.

Bone marrow biopsies form an important part of investigations into a large number of conditions in veterinary patients. In the human field, powered drivers specifically designed for the collection of bone marrow have become available. These systems have been shown to obtain better quality bone marrow, more quickly and with less pain. This study showed that a powered rotary bone marrow collection system could be used in dogs and cats to collect bone marrow, easily and without complications. Good quality bone marrow aspirates were obtained in the majority of patients; where aspirates could not be collected it was not possible to obtain aspirates from alternative sites using a standard manual technique. Bone marrow core samples were of increased size (mean useable area 16.5 mm(2)), compared to samples obtained using a standard manual technique (mean useable area 4.1 mm(2), P<0.001). Samples obtained using the powered system were also judged to be of significantly better diagnostic quality. The use of a powered system for bone marrow collection may aid the collection of better quality bone marrow samples in small animal patients.

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.

Hypercalcaemia associated with granulomatous lymphadenitis and elevated 1,25 dihydroxyvitamin D concentration in a dog.

A seven-year-old Labrador was presented with weight loss and mild generalised lymphadenopathy. Histopathology of an excised lymph node by the referring veterinarian demonstrated granulomatous lymphadenitis. At the time of referral, fine-needle aspirates of the lymph nodes confirmed the presence of ongoing granulomatous inflammation. Further investigations revealed marked hypercalcaemia, a low parathyroid hormone concentration, a parathyroid hormone related protein concentration within the reference range, and an elevated serum concentration of 1,25 dihydroxyvitamin D. An underlying cause of the granulomatous lymphadenitis could not be identified. The clinical signs, hypercalcaemia and elevated serum concentrations of 1,25 dihydroxyvitamin D resolved following prednisolone treatment. In contrast to dogs, hypercalcaemia occurred secondarily to granulomatous disease and elevated 1,25 dihydroxyvitamin D concentrations is a well-recognised condition in human beings. To the authors' knowledge, this is the first case report to describe elevated serum calcium and 1,25 dihydroxyvitamin D concentrations in a dog with histologically confirmed granulomatous disease.

Clinicopathological features of seven cases of canine myelofibrosis and the possible relationship between the histological findings and prognosis.

Seven dogs with non-regenerative anaemia were diagnosed as having myelofibrosis on the basis of the presence of collagen and increased deposits of reticulin fibre in the haemopoietic spaces of bone marrow core biopsies. A scoring system was used to assess the cellularity of the marrow and the amounts of collagen, reticulin and haemosiderin present. These scores, together with the haematological findings, were compared with the dogs' responses to treatment and their outcome. Treatment consisted of blood transfusions, where required, and anabolic steroids and corticosteroids. Three dogs deteriorated and were euthanased within three months of diagnosis, but the other four recovered fully. There was no correlation between the collagen and reticulin scores, or the degree of anaemia and the outcome, but the four dogs which recovered all had a macrocytosis when first examined. There was no evidence of an underlying lymphoproliferative or myeloproliferative disease in any of the seven cases.