Breed differences in the proportional morbidity of testicular tumours and distribution of histopathologic types in a population-based canine cancer registry.

Histologically verified tumours submitted to the Norwegian Canine Cancer Register from 1990 to 1998 were studied (n=14,401). The proportion of testicular tumours (n=345) was 2.4%, and the breakdown of histological tumour diagnoses is presented. The frequency of the most common histopathological types was 33% interstitial (Leydig), 26.4% Sertoli and 33.9% seminomas/germ cell tumours. The average age at diagnosis was 10 years, but was significantly lower for Sertoli cell tumours (8.6 years) than for the other tumour types. Following a histopathological re-evaluation, 22.5% of the original tumor diagnoses were modified. Proportional morbidity ratios were calculated and individuals from the breeds Shetland sheepdog and Collie were five times more likely to have testicular tumours than the overall average for the registry. Breed differences in the distribution of histopathologic types were observed. Shetland sheepdog and Collie were most commonly diagnosed with Sertoli cell tumours, while all tumours from Norwegian elkhound in this material were seminomas.

Renal microcystic tubular lesions in two 1Year-old dogs - an early sign of hereditary renal cystadenocarcinoma?

As a part of a study of early renal changes in renal cystadenocarcinoma (RC), a 5-year-old German shepherd dog and two 1-year-old German shepherd mixed-breed dogs were examined. All three animals had bilateral, microscopic renal cysts, and the 5-year-old dog also had RC. Microscopical examination showed papillary hyperplastic tubular epithelial cells lining the inner wall of the renal cysts in all dogs. These cells showed strong reactivity with a monoclonal antibody against a broad-spectrum type of cytokeratin. The dam of the young dogs had suffered from autosomal dominant inherited RC and nodular dermatofibrosis (ND) syndrome. It is likely that the microscopic renal cystic lesions seen in the young dogs represented an early renal change in the RC/ND syndrome. This suggests that the diagnosis of RC can be made on suspected carriers by microscopical examination of renal biopsies as early as 1 year of age, i.e., before the dogs are used for breeding.

Genetic mapping of a naturally occurring hereditary renal cancer syndrome in dogs.

Canine hereditary multifocal renal cystadenocarcinoma and nodular dermatofibrosis (RCND) is a rare, naturally occurring inherited cancer syndrome observed in dogs. Genetic linkage analysis of an RCND-informative pedigree has identified a linkage group flanking RCND (CHP14-C05.377-C05.414-FH2383-C05. 771-[RCND-CPH18]-C02608-GLUT4-TP53-ZuBe Ca6-AHT141-FH2140-FH2594) thus localizing the disease to a small region of canine chromosome 5. The closest marker, C02608, is linked to RCND with a recombination fraction (theta) of 0.016, supported by a logarithm of odds score of 16.7. C02608 and the adjacent linked markers map to a region of the canine genome corresponding to portions of human chromosomes 1p and 17p. A combination of linkage analysis and direct sequencing eliminate several likely candidate genes, including tuberous sclerosis 1 and 2 genes (TSC1 and TSC2) and the tumor suppressor gene TP53. These data suggest that RCND may be caused by a previously unidentified tumor suppressor gene and highlight the potential for canine genetics in the study of human disease predisposition.

Internal radionuclide therapy of primary osteosarcoma in dogs, using 153Sm-ethylene-diamino-tetramethylene-phosphonate (EDTMP).

Fifteen dogs were referred because of a spontaneous bone tumor, lameness, and local pain. The osteosarcoma diagnosis was established by clinical examination, X-ray, bone scintigraphy, and histological examination of biopsy material. The tumors were located in the extremities (n = 12), scapula (n = 1), maxilla (n = 1), and the frontal bone (n = 1). The dogs were given one to four i.v. injections of 153Sm-labeled ethylene-diamino-tetramethylene-phosphonate (153Sm-EDTMP; 36-57 MBq/kg body weight). Three dogs had surgery in addition to the radionuclide treatment. Platelet and WBC counts showed a moderate and transient decrease. No other toxicity was observed. Average tumor doses after a single injection were approximately 20 Gy, considerably higher in some areas because of inhomogeneous uptake. Macroscopically distant metastases were detected in seven dogs at autopsy. One dog died from an intercurrent disease, free of cancer, 5 months after the radionuclide treatment. None of the dogs was cured. The median and mean survival times from the first treatment to death or euthanasia were 150 and 252 days, respectively. Nine of the dogs had obvious pain relief, and five of them seemed pain-free: one for 20 months and one for 48 months. It is concluded that high tumor doses may be deposited in dog osteosarcomas by 153Sm-EDTMP, and the ratio between tumor dose and the dose to surrounding tissues is favorable. The treatment gives pain relief and in some cases tumor growth delay. In combination with surgery, 153Sm-EDTMP may prolong life significantly and possibly cure the disease because the development of metastases are seemingly postponed. No serious side effects were observed.

Maxillectomy and targeted radionuclide therapy with 153Sm-EDTMP in a recurrent canine osteosarcoma.

An eight-year-old dog with a local relapse of an osteosarcoma was treated with partial maxillectomy and systemic radionuclide therapy that involved two injections, 43 and 45 megabecquerels per kg bodyweight of the bone-seeking agent samarium-153-ethylenediaminetetramethylene phosphonic acid (153Sm-EDTMP), 15 weeks apart. A transient drop in white blood cell count and platelet count was observed following each 153Sm-EDTMP treatment. Follow-up 21 months after surgery revealed no evidence of local recurrence or metastases. The dog was in excellent condition, suffering only minor sequelae from the surgical procedure. Compared with historical controls treated with surgery alone, the combination of surgery and systemic radionuclide therapy seems a promising strategy for the treatment of canine osteosarcoma.

[Registration of canine cancer]. / Registrering av kreft hos hund.

A Norwegian Canine Cancer Registry, covering four of 19 counties, has been operative since March 1990. Until the end of April 1994 about 6,000 tumours have been registered, more than 50% of these being manifestly or potentially malignant. Among 14 selected breeds the relative risk ratio for all tumours varies with factor 35 from boxer to dunker, the boxer having the highest tumour risk. The percentage distribution of specified tumour types also varies greatly between breeds, mammary cancer constituting 59% of all neoplasms in the dachshund, but only 4% in the Bernese mountain dog. Because of the genetic diversity between breeds the dog is a suitable species for differentiation between genetically determined predisposition and environmental influences in the etiology of cancer. Epidemiological surveillance of cancer morbidity in dogs may be a useful instrument for tracing carcinogens, even in the surroundings of man.

An outbreak of mucosal disease in a dairy herd.

An outbreak of mucosal disease (MD) was studied in a dairy herd, comprising 12 cows, 9 heifers and 18 calves. During a period of 1 month, six 5 to 8 month-old calves showed typical signs of MD. They all died or were killed in extremis after 2-8 days with progressively worsening clinical signs. Post mortem lesions were examined in one calf. Non-cytopathogenic MD virus was isolated from serum or tissues from 3 clinically affected calves and from 1 healthy heifer. All cows and heifers except for the viremic one possessed neutralizing antibodies against bovine pestivirus. According to the current MD-pathogenesis concept, the affected calves were probably infected transplacentally during the first half of foetal life with pestivirus from the persistently infected heifer in the herd.

Intestinal lymphangiectasia in the Lundehund. Scanning electron microscopy of intestinal mucosa.

Intestinal lymphangiectasia of obscure etiology is frequent among Norwegian Lundehunds ("puffin-dog"). A study of three Lundehunds with typical symptoms, including wasting, diarrhea and ascites, revealed segmental distention of lymphatics resembling primary lymphangiectasia in man. Atrophy, fusion and balloon-like swelling of villi with occasional rupture of lacteals were seen. Subepithelial fluid accumulation caused bulging of the epithelium. Microvilli showed partial or complete atrophy. The protein loss in the Lundehund enteropathy may be due to rupture of lacteals, increased paracellular permeability, caused by enhanced hydrostatic tissue pressure, and decreased absorption through a malformed brush border.

A sarcocystis-like protozoon in a sheep with lymphadenopathy and myocarditis.

A generalized enlargement of the lymph nodes was found in an emaciated adult ewe. Additional autopsy findings included tiny grey-white necrotic foci in the heart muscle, aspiration pneumonia and diffuse pleuritis. Light microscopy showed a generalized lymphadenopathy with perilymphadenitis, depletion of lymphocytes and histiocytosis of the lymph node. In histiocytes and vascular endothelial cells of lymph nodes, septal capillary endothelium of lungs and capillary endothelium of myocardium, early stages of a protozoan parasite were found. In the myocardium, there were many foci of necrosis, some of which contained young cysts in the periphery. These cysts were morphogically similar tho those of Sarcocystis. Electron microscopy of the early protozoan stages yielded evidence of schizogony and formation of merozoites.