Nonhematopoietic neoplasms in cats.

In a study of 3,145 feline necropsies conducted for 11 years by the pathology department of The Animal Medical Center, 289 tumors of nonhematopoietic origin were found in 264 cats. Malignant and epithelial tumors were more common than benign or mesenchymal tumors in all ages and breeds, and in both sexes. They were also more common in female cats than in males, even after mammary neoplasms were excluded. Analysis of groups of tumors according to their tissue of origin indicated some sex and breed dispositions not observed before. Pulmonary carcinomas and osteosarcomas were more frequent in domestic short haired cats than in other breeds, whereas intestinal carcinomas occurred more often in Siamese cats. Female predominated in pulmonary carcinomas, hemangiosarcomas, osteosarcomas, and squamous cell carcinomas, but males outnumbered the females in intestinal carcinomas.

Estrogen receptors in canine mammary tumors.

The presence of estrogen receptor in 67 canine mammary lesions was correlated with pathological features of the disease. All tissue specimens were analyzed for estrogen receptor content by a sucrose gradient ultracentrifugation method previously used in analyzing human breast cancer cytosols. Pathological features of the tissues were assessed by a veterinary pathologist without knowledge of results of estrogen receptor analysis. Sixty-two (92.5%) of the tissue samples analyzed were classified as epithelial neoplastic lesions, and 38 of these (61.3%), including 24 adenocarcinomas, were estrogen receptor for positive (i.e., estrogen receptor concentration equal to or greater than 10 fmol/mg cytosol protein). All five of the nonepithelial neoplastic lesions were estrogen receptor negative. Canine and human breast cancers share common histological types and have similar biological behavior. If a significant percentage of canine mammary cancer is also estrogen dependent, the dog may be a useful model for hormonal studies and for the development of models of endocrine therapy for human breast cancer.

Argyrophilic, intracellular bacteria in some cats with idiopathic peripheral lymphadenopathy.

Lymph node biopsy specimens from several previously reported cases of unusual feline peripheral lymphadenopathies were re-examined by a modified Dieterlé silver-impregnation staining technique. In a proportion of these specimens, the Dieterlé stain revealed tiny pleomorphic, intensely argyrophilic coccobacilli. These organisms were predominantly located within macrophages. The infected cells were focally distributed, particularly in the interfollicular regions of the nodes. They were inconspicuous in sections stained by other, more conventional staining methods. It is possible that these coccobacilli represent yet another, previously unidentified, cause of chronic lymph node hyperplasia in the cat.

Clinical signs of tumors affecting the rostral cerebrum in 43 dogs.

The clinical and pathologic features of 43 dogs with neoplasia of the rostral cerebrum were reviewed. Primary brain tumors included meningioma, astrocytoma, neuroblastoma, oligodendroglioma, and ependymoma. Other tumors that secondarily affected these areas included solitary hemangiosarcoma, nasal neuroendocrine carcinoma, nasal cell adenocarcinoma, nasal squamous cell carcinoma, and nasal neurofibrosarcoma. Older dogs were usually affected (mean, 10 years), and meningioma was the most frequent tumor type. Thirty-one dogs (72% of total) had a late-onset (greater than 5 years of age) of either generalized seizures or behavior abnormalities, or both, with an initially normal neurologic examination. In these 31 dogs, a mean time of 78 days (range, 2 to 400 days) elapsed from the onset of seizures or behavior change to the detection of a persistently abnormal neurologic examination. In all 43 dogs, the time from the detection of neurologic deficits to death or euthanasia and necropsy ranged from 1 to 63 days (mean, 13 days). On the basis of this review, it appears that dogs with late-onset seizures or behavior change, or both, should be suspected of having tumors involving the rostral cerebrum, despite the absence of persistent neurologic deficits commonly associated with cerebral tumors. Further, the onset of abnormalities in the neurologic examination and the time of death seem to occur within predictable time periods.

Prognostic factors in dogs with lymphoma and associated hypercalcemia.

Lymphoma and hypercalcemia were diagnosed in 37 dogs. Twenty-six of the dogs received chemotherapy. The association between some prognostic factors including clinical stage of disease, illness status, presence of bone marrow involvement, and presence of an anterior mediastinal mass and remission duration and survival time was evaluated. Statistical analysis of the prognostic factors showed that the presence of an anterior mediastinal mass had an adverse effect on remission duration (P less than 0.03). Calcium concentration was not significantly related to any of the prognostic factors evaluated. Dogs that received chemotherapy were more likely to be self-supporting than the dogs that were not treated (P less than 0.005). However, initial illness status was not significantly related to remission duration or survival time in the 26 dogs that were treated. Six dogs (25% of dogs treated) survived longer than 14 months. Five of these dogs were female. Overall mean and median remission times were 10.4 and 6 months, respectively.

Canine osteosarcoma. Treatment by amputation versus amputation and adjuvant chemotherapy using doxorubicin and cisplatin.

Osteosarcoma was diagnosed in 38 dogs. Thirty-six tumors originated from the appendicular skeleton and two from the axial skeleton. Nineteen of the dogs were treated with amputation alone, and 19 were treated with amputation and adjuvant chemotherapy consisting of doxorubicin and cisplatin. The 36 dogs with appendicular osteosarcoma had complete amputation of the affected limb, whereas the two dogs with osteosarcoma of the axial skeleton had an en bloc resection. The mean survival of the 19 dogs treated with amputation alone was 218 days (median, 175 days). Ten dogs were alive at 6 months and four survived 1 year. None of the dogs survived longer than 16 months. Radiographic lesions consistent with metastatic osteosarcoma were seen after surgery in the nine dogs in which radiographs were taken. The mean survival of the 19 dogs treated with amputation and chemotherapy was 415 days (median, 300 days). Drug toxicity was not observed. Fifteen dogs were alive at 6 months, seven dogs were alive at 1 year, 5 dogs were alive at 2 years, and two dogs were alive at 3 years or longer. One dog is alive and well at 25 months. Radiographic lesions suggestive of metastatic osteosarcoma developed in the other 18 dogs. The 19 dogs treated with amputation and chemotherapy had significantly longer survival times than the dogs treated with amputation alone.

Chemotherapy versus chemotherapy plus radiotherapy in the treatment of tonsillar squamous cell carcinoma in the dog.

The effect of adjuvant chemotherapy and combined chemotherapy and radiotherapy in 22 dogs with advanced canine tonsillar carcinoma (World Health Organization [WHO], T2-3 primary tumor with infiltration into surrounding tissues) was evaluated. There were four treatment groups of at least five dogs each. Combinations of chemotherapeutic drugs reported to have activity against squamous cell carcinoma in humans and dogs (doxorubicin, cisplatin, vinblastine, and cyclophosphamide) were administered after tonsillectomy. Radiation therapy (orthovoltage type, external beam) was combined with chemotherapy in one treatment group. The dogs that had combination radiation therapy and chemotherapy had higher response rates and significantly longer survival times. However, most dogs died of progression of disease.

Efficacy and toxicity of doxorubicin and cyclophosphamide used in the treatment of selected malignant tumors in 23 cats.

Twenty-three cats with malignant, nonhematopoietic tumors were treated with doxorubicin and cyclophosphamide. Fourteen cats had nonresectable tumors of the mammary gland, and nine had tumors of the oral cavity. Of the cats with mammary gland adenocarcinoma, seven cats had a partial response to treatment and seven cats had no response. Of the cats with oral tumors, one cat had a complete response, three cats had a partial response, and five cats had no response. All 23 cats are dead because of tumor progression or recurrence. Toxic effects were seen in 18 of the cats; most were transient and required no alteration in the treatment protocol. A high response rate combined with acceptable toxicity warrants further evaluation of combination doxorubicin and cyclophosphamide chemotherapy in cats with nonhematopoietic neoplasia.

Prognostic factors in dogs with urinary bladder carcinoma.

Medical records and biopsy specimens were retrospectively reviewed from 25 dogs diagnosed with unresectable urinary bladder carcinoma and treated with chemotherapy. Our intention was to identify clinical, histologic, and immunohistochemical indicators of prognosis. Immunohistochemical stains for P-glycoprotein, glutathione-S-transferase pi, and factor VIII-related antigen were applied to archived tissue. There were more spayed female dogs than castrated male dogs (76% versus 24%). Transitional cell carcinoma was the most common tumor (88%, n = 22), followed by undifferentiated carcinoma (8%, n = 2) and squamous cell carcinoma (4%, n = 1). Overall median survival was 251 days. Histologic diagnosis and immunohistochemical characteristics did not correlate with prognosis. Spayed females survived significantly longer than castrated males (358 days versus 145 days, P = .042). Dogs that received either doxorubicin or mitoxantrone in addition to a platinum-based chemotherapeutic (either cisplatin or carboplatin) lived significantly longer than those that received only a platinum compound (358 days versus 132 days, P = .042).

A prospective study of radiation therapy for the treatment of grade 2 mast cell tumors in 32 dogs.

Surgery, chemotherapy, and irradiation have been used singly or in combination to treat dogs with cutaneous grade-2 mast cell tumors (MCT). However, optimal treatment has not been established. At The Animal Medical Center, 32 dogs with grade 2, stage 0 MCT received cobalt radiation treatment to a dose of 54 Gy; 94% had a disease-free interval of 1 year. The 2-,3-,4-, and 5-year disease-free intervals were 86%. Survival rates were 100% for 1 year and 96% for 2 to 5 years, with only 1 death caused by MCT. Primary site was not a prognostic factor for survival in this study. Minimal toxicity was observed and was limited to acute cutaneous reactions. Late-term reactions to radiation therapy were mild and considered acceptable in all cases. No deaths occurred due to treatment, and no dog was eliminated from the study because of radiation therapy toxicity. Radiation therapy appears to be an effective treatment for dogs with grade 2, stage 0 MCT.

Doxorubicin-induced cardiotoxicosis. Clinical features in 32 dogs.

Clinical cardiac abnormalities developed in 32 of 175 dogs that had various malignancies and were treated with doxorubicin: 31 dogs had electrocardiographic abnormalities including arrhythmias and nonspecific alterations in the R wave, ST segment, or QRS duration and 7 dogs had congestive heart failure. All seven dogs that had congestive heart failure died within 90 days. At necropsy, 13 of 32 affected dogs had noninflammatory myocardial degeneration, myocytolysis, vacuolation, and/or fibrosis and there was intramural coronary arteriosclerosis in all 13. Five dogs with lymphosarcoma were in complete clinical remission when they died of doxorubicin-induced cardiomyopathy, but the overall survival times of the lymphosarcoma subset was nevertheless longer than in previous studies. The clinical use of doxorubicin in the dog can cause cardiotoxicosis but the therapeutic benefit appears to outweigh risks in most dogs.

Ectopic lingual thyroid tissue in a cat.

Ectopic thyroid tissue was identified at the base of the tongue in a 9-year-old, euthyroid, domestic shorthair cat. The lingual submucosa and the muscles were replaced by thyroid tissue, which consisted of various-sized follicles each lined by a row of cuboidal epithelium. Many follicles contained eosinophilic, periodic acid Schiff-positive, colloid material. Imunohistochemically, the epithelial cells stained positive for AE(1)/AE(3)and thyroglobulin. No calcitonin positive cells or parathyroid tissue was seen. The cat has been followed for 1018 days after surgery, is clinically well and remains euthyroid.

Feline cystic thymoma: a clinicopathologic, immunohistologic, and electron microscopic study of 14 cases.

Cystic thymoma was diagnosed in 14 cats in a period of 6 years. The most common clinical sign was laboured breathing. The tumours were characterized by various-sized cystic spaces with central vessels. The epithelial cells varied from oval to spindle to polygonal cells enclosing cystic spaces or in pure epithelial cell components. The nuclei of the neoplastic cells had scattered chromatin and small nucleoli. The cytoplasm was pale eosinophilic. The concentration of mature lymphocytes varied from area to area with rare germinal centres. Immunohistochemically, the epithelial cells stained only with AE(1)/AE(3). The central vessels were positive for vimentin, smooth muscle actin, and factor VIII antigen. Electron microscopy revealed that the cyst walls were lined by epithelial cells that were joined by desmosomes, and the walls were well separated from the cystic spaces by a well-defined basement membrane. The neoplastic epithelial cells contained scattered tonofilaments. Three of the cats had metastasis to the lymph nodes and lungs. Two novel cases of ectopic cystic thymoma have also been described. Results of this study reveal that cystic thymoma is uncommon in cats, and that the histomorphologic, immunohistochemical, and electron microscopic features are similar to those of cystic thymoma in humans.

Nonhematopoietic hepatic neoplasms in cats: 21 cases (1983-1988).

Nonhematopoietic hepatic neoplasms (n = 25) were diagnosed in 21 cats during a 5.5-year period. Thirteen of the neoplasms were benign bile duct adenomas and 12 were malignant, 6 of which were bile duct adenocarcinomas. All cats were greater than or equal to 10 years old, and 14 were male. Main clinical signs were anorexia and lethargy, and 15 of 21 cats had hepatomegaly. All 21 cats were feline leukemia virus-test negative. Although there was a trend toward high activities of serum alanine transaminase and aspartate transaminase, neither clinical signs nor enzyme activity were specific for diagnosis of hepatic neoplasia in the cats of this study.

Malignant anterior uveal melanoma with diffuse metastasis in a dog.

Enucleation was performed in 10-year-old sexually intact female mixed-breed German Shepherd Dog. Histologic examination revealed that the dog had an uveal amelanotic melanoma of the eye. The tumor consisted of anaplastic cells with a high mitotic index, indicating malignancy. On examination 3 months after enucleation, the dog had difficulty breathing and nasal discharge. Radiography revealed pulmonary metastasis. The dog was euthanatized. Necropsy revealed diffuse metastasis involving various organs.

Intravenous leiomyoma of the bladder in a cat.

An intravenous leiomyoma was diagnosed in a 5-year-old male cat that had a history of listlessness, dysuria, and hematuria. The cat has been clinically normal for 25 months after excision of the neoplasm.

Thymic branchial cysts in the dog and cat.

Branchial cysts of the thymus were diagnosed in 15 dogs and 2 cats. The main clinical sign was dyspnea. Pleural effusion varied in degree from minimal to severe. In all animals, an encapsulated mass in the cranial mediastinal region was found to consist of multiple epithelial cysts embedded in a stroma of fibrous connective tissue, adipose tissue, and vessels. Surgical resection of the cysts was performed in 7 dogs; 3 dogs survived and were clinically normal for 18 to 36 months.

Cerebral astrocytoma in four cats: clinical and pathologic findings.

Cerebral astrocytoma was diagnosed in 4 cats. A long-standing history of seizures followed by an increase in frequency of uncontrolled seizures were prominent features in these cats. Anticonvulsants provided effective seizure control in 3 cats for a period of 1 to 3 years. On initial and subsequent neurologic examinations, all cats were postictal and had focal neurologic deficits. In 2 cats, there were focal EEG patterns consistent with the neuroanatomic diagnosis of the tumor. White blood cell pleomorphism of the CSF was determined in the cats that underwent CSF analysis. Pathologic findings in all cats included tumor necrosis and edema, compression of the opposite hemisphere, and invasion of the third and lateral ventricles.

Hepatopathy associated with excessive iron storage in mynah birds.

Hepatic disease was diagnosed in 11 mynah birds. The most common clinical signs were dyspnea, weight loss, and abdominal swelling, usually accompanied by ascites. Radiography (9 birds) revealed hepatomegaly and ascites in most cases, and laboratory testing (6 birds) revealed hypoproteinemia and high activity of liver enzymes in all cases. Histologic examination (6 birds) revealed variable amounts of iron granule accumulation in hepatocytes, indicating hemochromatosis. Therapy consisted of administration of diuretics and abdominocentesis in dyspneic birds. All birds died, with survival time ranging from 1 day to 1 year.

Small intestinal adenocarcinoma in cats: 32 cases (1978-1985).

The medical records of 32 cats with small intestinal adenocarcinoma were reviewed. Common clinical signs included vomiting, dehydration, weight loss, cachexia, anorexia, and lethargy. In 50% of the cats, an abdominal mass was palpated, and in 38%, a mass was seen on radiographs. Biopsy of the tumor without resection was performed in 9 cats; 8 cats were euthanatized at the time of surgery, 7 because of metastases, and 1 cat died 1 day after surgery. In 23 cats, resection was performed. Eleven of these died within 2 weeks after surgery (mean survival time, 2.6 days); 8 had lymph node metastasis. Twelve cats survived greater than 2 weeks after surgery. The mean survival of 11 of these cats was 15 months. Six cats were euthanatized because of recurrent signs; 5 of the 6 had a recurrent abdominal mass. One cat was alive 2 years after surgery. Results of this study indicated that cats with adenocarcinoma, even those cats with advanced disease, can have long-term survival after surgery.