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.

An epidemiological analysis of a canine-biopsies database compiled by a diagnostic histopathology service.

A case-control study was carried out on data from 21,371 canine tissue biopsies submitted to the external histopathology diagnostic service at the University of Glasgow Veterinary School (GUVS) over a 12.5-year period. Biopsies were received from 545 privately owned and charity veterinary practices located throughout the UK. The overall prevalence of neoplasia in samples with a confirmed diagnosis was 58.7%. A total of 156 pure breeds were represented in the dataset, with 22.2% of samples originating from mixed-breed dogs. Univariable and multivariable analyses assessed the effects of sex, breed, age and site on the likelihood of a diagnosis of neoplasia. Logistic regression showed that the highest odds ratio was associated with the mammary gland (OR=6.53;skin=the referent category). Using the Labrador retriever as the referent breed, Boxers had increased odds of neoplasia; the German shepherd dog and Doberman were among breeds with decreased odds ratios. Intact females and dogs over the age of 10 years were (unsurprisingly) also high-risk groups. Potential sources of bias influencing the dataset include the relative ease with which clinical abnormalities of the skin and mammary gland initially are detected by sight and/or palpation, compared with other organs. The high prevalence of biopsies originating from the skin and mammary gland is also likely to reflect the readiness of the veterinarian to biopsy lesions in these sites, compared with sites within the body cavities. The findings confirm many of the perceived risks for neoplasia based on previous clinical descriptive and univariable investigations. The results might also assist the pathologist in prioritisation of biopsy examination in busy histopathology laboratories.

Ultrasonographic detection of a pancreatic glucagon-secreting multihormonal islet cell tumour in a dachshund with metabolic epidermal necrosis.

The clinical, ultrasonographic and histopathological features of a pancreatic multihormonal islet cell tumour are described in a 12-year-old dachshund with cutaneous lesions suggestive of metabolic epidermal necrosis. This condition was suspected because of the compatible cutaneous signs, a high plasma glucagon concentration and the detection of a well defined pancreatic mass by ultrasonography. The diagnosis was confirmed postmortem and by histology.

Malignant articular plasmacytoma in two dogs.

Malignant articular neoplasia in two dogs was diagnosed as plasma cell neoplasia on the basis of radiography and cytology, and was supported by histopathology. Both dogs were euthanased and widespread metastases were identified postmortem.

Metabolic epidermal necrosis in two dogs with different underlying diseases.

Two dogs with metabolic epidermal necrosis had hyperkeratosis of the footpads accompanied by erythematous, erosive and crusting lesions affecting the muzzle, external genitalia, perineum and periocular regions. Histopathological examination of skin biopsies revealed a superficial hydropic dermatitis with marked parakeratosis. Both dogs had high plasma activities of alkaline phosphatase and alanine aminotransferase and high concentrations of glucose, and also a marked hypoaminoacidaemia. Despite these similarities, the cutaneous eruptions were associated with different underlying diseases. One dog had a pancreatic carcinoma which had metastasised widely; the primary tumour and the metastases showed glucagon immunoreactivity on immunocytochemical staining, and the dog's plasma glucagon concentration was markedly greater than that of control dogs. The other dog had diffuse hepatic disease; its plasma glucagon concentration was similar to that of control samples and cirrhosis was identified post mortem. Metabolic epidermal necrosis in dogs is a distinct cutaneous reaction pattern which may be associated with different underlying systemic diseases; however, the pathogenesis of the skin lesions remains unclear.

Canine eosinophilic folliculitis and furunculosis in three cases.

The historical, clinical and histopathological features of three dogs with eosinophilic folliculitis and furunculosis are described. The disease was characterised by the rapid development of pruritic, papular, pustular and ulcerative lesions on the dorsum of the muzzle. Skin lesions were confined to the face in two cases. The third dog had more generalised pustular lesions. Skin biopsy specimens showed marked eosinophil infiltration particularly centred on pilosebaceous units. Dermal collagen necrosis was evident in two cases. Similar facial lesions have previously been described as 'nasal pyoderma'. The three dogs failed to respond to initial antibacterial therapy but showed a rapid clinical response when prednisolone was given orally at doses ranging from 1 to 2.2 mg/kg, in addition to the antibacterial therapy, suggesting that glucocorticoids are indicated for the treatment of eosinophilic folliculitis and furunculosis. The aetiology of the disease was not determined.

Acute tubulo-interstitial nephritis in a dog after halothane anaesthesia and administration of flunixin meglumine and trimethoprim-sulphadiazine.

Acute tubulo-interstitial nephritis was diagnosed post mortem when a dog died four days after surgery for a femoral head resection. Possible causative factors associated with halothane anaesthesia, flunixin meglumine analgesia and prophylactic antibiotic therapy with trimethoprim-sulphadiazine are discussed. It is concluded that death was due to renal failure associated with tubulo-interstitial nephritis as a result of a combination of ischaemic and toxic events.

An atypical case of lymphosarcoma (sporadic bovine leukosis) in a heifer.

An 18-month-old Friesian heifer had several unusual, raised, black, cutaneous plaques, some of which were up to 20 cm in diameter, on its head and neck, limbs, thorax and perineum. There was also generalised lymphadenopathy. A clinical diagnosis of lymphosarcoma (sporadic bovine leukosis) was derived from a fine needle aspiration of a skin lesion. Post mortem and histological examinations confirmed a multicentric lymphosarcoma with widespread infiltration into many of the tissues recognised as predilection sites for this type of tumour. However, in the authors' experience, the presence of tumour masses in the trachea and the right mainstem bronchus was atypical.

Massive scrotal swelling in two unusual cases of canine sertoli-cell tumour.

Two cases of Sertoli-cell tumour in dogs in which the presenting sign was a partially reducible scrotal swelling are described. In one animal intravenous extension of the tumour had led to varicosity of the testicular vein while lymphatic extension had resulted in the formation of both sublumbar and intrathoracic growths. In the second animal there was massive hydrocoele and some varicosity of the distal testicular vein and there was again lymphatic spread with tumours in the sublumbar lymph nodes and the spleen. Both animals showed changes considered to be evidence of feminisation.

High incidence area of cattle cancer with a possible interaction between an environmental carcinogen and a papilloma virus.

Cattle in upland areas of Scotland and northern England are substantially more prone to alimentary cancer than those of the immediately neighbouring lowlands, and epidemiological evidence implicates a combination of papilloma virus and bracken in the aetiology of the disease. Here Professor Jarrett outlines the circumstantial case against these agents and discusses its implications.