Clinical and pathologic features of thyroid tumors in 26 dogs

Thyroid tumors were diagnosed in 26 dogs between 1977 and 1984. A total of 23 of the 26 tumors were carcinomas, and 3, detected as incidental findings at necropsy, were adenomas. The median patient age was 9.5 years. Dogs of the Beagle breed were affected most commonly (5 dogs). The most common physical abnormalities in carcinoma patients were cervical swelling, dyspnea, and coughing. A total of 25 of 26 dogs were clinically euthyroid. Aspiration cytology provided diagnostic information in 8 of 17 cases. In dogs with thyroid carcinoma, a cervical soft tissue lesion was identified consistently by use of radiography and scintigraphy with sodium pertechnetate. Pulmonary metastases were detected radiographically in 8 of 21 dogs with thyroid carcinoma. Thoracic nuclear imaging confirmed the radiographic findings in 11 of 14 dogs. Surgical excision of the thyroid mass was the primary treatment for 17 dogs with carcinoma. Eight dogs died within 2 years (median, 7 months) of surgery because of primary tumor regrowth or metastases. Four dogs were alive at a range of 3 to 48 months after surgery, and 4 dogs died from unrelated causes. Necropsy of 7 dogs with thyroid carcinoma revealed neoplastic infiltration of the cervical blood vessels and pulmonary metastases in each dog. The most common histologic patterns of thyroid carcinoma were solid or compact cellular (11 dogs) and mixed solid-follicular tumors (8 dogs). Dogs with a solid carcinoma had a median survival time of 10.5 months (6 dogs), and dogs with a mixed solid-follicular tumor had a median survival time of 8 months (3 dogs).     

Canine hepatic neuroendocrine carcinoma: an immunohistochemical and electron microscopic study

Ten dogs with neuroendocrine carcinoma of the liver were selected for inclusion in the study. Clinical signs were anorexia (7), vomiting (5), polydipsia/polyuria (3), icterus (2), lethargy (2), weight loss (2), paresis (1), ataxia (1), weakness (1), collapse (1), and urinary tract infection (1). Hematologic and biochemical abnormalities included anemia (2/8), leukocytosis (4/8), high liver enzyme activity (serum alkaline phosphatase, 7/9; alanine transaminase, 7/9; aspartate transaminase, 8/9), and high total bilirubin (6/9). Grossly, the tumors were diffuse, involving all liver lobes in six dogs, and two dogs had various-sized nodules in addition to diffuse involvement. Histologically, there were eight tumors with solid or trabecular pattern (group A), one tumor with cords or rows of neoplastic cells (group B), and one tumor with multiple rosette-like structures (group C). Immunohistochemical studies revealed that all 10 neoplasms were positive for at least one of the endocrine markers used: neuron-specific enolase (NSE; 8/10), synaptophysin (5/10), and chromogranin-A (3/10). A panel of NSE, chromagranin-A, and synaptophysin detected 100% of the tumors in our series. Electron microscopy confirmed the diagnosis by the presence of intracytoplasmic neurosecretory granules in the two examined cases. Our results show that neuroendocrine markers commonly used in humans can be used for the diagnosis of hepatic neuroendocrine carcinoma in dogs, preferably a panel of synaptophysin, chromagranin-A, and NSE because chromogranin-A alone is not as useful in dogs as in humans.     

Neurologic abnormalities as the predominant signs of neoplasia of the nasal cavity in dogs and cats: seven cases (1973-1986)

Neurologic abnormalities were the predominant historic and physical findings in 5 dogs and 2 cats with primary nasal cavity tumors that had invaded the cranial vault. Seizures, behavior changes, and obtundation were the most common signs. Other neurologic signs included paresis, ataxia, circling, visual deficit, and proprioceptive deficit. Although 1 dog and 2 cats had historic findings of mild respiratory disease, no physical abnormalities related to the respiratory tract were found in any of the 7 animals. Nasal cavity neoplasia was suggested by radiographic and computed tomographic studies and was confirmed histopathologically in each case. The nasal tumor types in the 5 dogs were epidermoid carcinoma (n = 1), adenocarcinoma (n = 2), solid carcinoma (n = 1), and anaplastic chondrosarcoma (n = 1). An esthesioneuroblastoma was found in each cat. Radiation therapy was effective for 3 months in palliating the clinical signs in the 2 dogs in which it was used. Neoplasia of the nasal cavity should be considered in the differential diagnosis for animals with neurologic signs suggestive of cerebral disorders.     

Gastric neoplasia.

Gastric tumors are rare in dogs and cats but should always be considered, particularly in older dogs with chronic vomiting. The most common gastric tumor in dogs is carcinoma, although lymphoma is rare. Breeds that seem to be predisposed to gastric carcinoma are the Rough Collie, Staffordshire Terrier, and Belgian Shepherd. Lymphoma is the most common gastric malignancy in cats. Contrast radiographic examination and endoscopy are the elective procedures of choice for the diagnosis of these conditions. Biopsy is essential to confirm the diagnosis. Surgery is the only potentially curative modality for localized gastric carcinoma. Chemotherapy alone or following surgery is the elective treatment of choice for gastric lymphoma in dogs and cats. The prognosis is poor for both types of tumor, but prolonged survival times in individual animals are possible.     

IMAGING FINDINGS IN PANCREATIC NEOPLASIA AND NODULAR HYPERPLASIA IN 19 CATS

Pancreatic neoplasia in cats is rare and associated with a poor prognosis, but pancreatic nodular hyperplasia is a common incidental finding. The purpose of this study was to describe radiographic and ultrasonographic findings in cats with pancreatic neoplasia or nodular hyperplasia. Fourteen cats (age 3-18 years) were diagnosed with malignant pancreatic tumors: carcinoma/adenocarcinoma (n = 11), lymphoma (n = 1), squamous cell carcinoma (n = 1), and lymphangiosarcoma (n = 1). The most common radiographic findings were an abdominal mass or mass effect (6/6) and lack of serosal margin detail (4/6). On ultrasound, the most common finding was a focal pancreatic mass or nodule, with a size range from 0.4 cm to more than 7.0 cm (8/14). Lymphadenopathy (7/14) and abdominal effusion (7/14) were frequently seen. Five cats (age 10-16 years) with adenomatous/nodular hyperplasia had an abdominal mass or mass effect as the most common radiographic finding (3/3). On ultrasound, all cats had multiple hypoechoic nodules between 0.3 and 1.0 cm associated with the pancreas. Other common findings were pancreatic thickening (2/5), lymphadenopathy (2/5), and abdominal effusion (2/5). The only imaging finding unique to malignant pancreatic tumors was the presence of a single pancreatic nodule or mass exceeding 2cm in at least one dimension (4/14). Although there was a tendency for neoplastic lesions to manifest as single larger lesions and for nodular hyperplasia to manifest as multiple smaller lesions, there was overlap of the imaging findings in both entities. Radiographs and ultrasound can complement but not replace cytology and histopathology in the diagnosis of feline pancreatic neoplasia.     

Radiographic appearance of pulmonary metastases from transitional cell carcinoma of the bladder and urethra of the dog

Eleven cases of histologically proven transitional cell carcinoma of the bladder or urethra of the dog were selected for evaluation and characterization of the varied radiographic appearances of the lungs. In the 8 dogs with metastases, those appearances included radiographically normal pulmonary parenchyma, a semidense, diffuse, lacelike haze referred to as interstitial opacity, nodular interstitial opacity, and consolidations. One affected dog had hilar lymphadenopathy. In the 3 dogs without pulmonary metastases, the radiographic appearance was either normal pulmonary parenchyma or increased unstructured interstitial opacity. Of all dogs in the study, 6 had a radiographic appearance of increased unstructured interstitial opacity. Four of those 6 had histologically proven metastases in the peribronchiolar lymphatics or alveolar capillaries. Dyspnea was not identified in any of the affected dogs. The radiographic appearance for 3 of the 8 dogs with pulmonary metastases was misinterpreted as opacity compatible with age. The radiographic appearance for 1 of the 3 dogs without pulmonary metastases was misinterpreted as highly suspect for metastases.     

RADIOGRAPHIC CHARACTERIZATION OF PRIMARY LUNG TUMORS IN 74 DOGS

Primary pulmonary neoplasia is well recognized in dogs and prognosis depends upon the tumor type. The purpose of this retrospective study was to characterize the radiographic appearance of different primary lung tumors with the goal of establishing imaging criteria to separate the different types. Three‐view thoracic radiographs of 74 dogs with histologically confirmed pulmonary anaplastic carcinoma (n = 2), adenocarcinoma (n = 31), bronchioalveolar carcinoma (n = 19), histiocytic sarcoma (n = 21), and squamous cell carcinoma (n = 1) were evaluated. Radiographs were assessed for tumor volume, affected lobe, location within lobe, overall pulmonary pattern, presence of cavitation, mineralization, air bronchograms, lymphadenomegaly, and pleural fluid. Histiocytic sarcomas were significantly larger than other tumor types (271 cm³; P = 0.009) and most likely to be found in the left cranial (38%; 8/21) and right middle (43%; 9/21) lung lobes, whereas adenocarcinomas were most likely to be found in the left caudal (29%; 9/31) lung lobe. Fifty‐seven percent (12/21) of histiocytic sarcomas had an internal air bronchogram. Findings indicate that a large mass in the periphery or affecting the whole lobe of the right middle or left cranial lung lobe with an internal air bronchogram is likely to be an histiocytic sarcoma.     

Combined hepatocellular and cholangiocellular carcinoma in a dog

A transitional type of combined hepatocellular and cholangiocellular carcinoma developed in a 12-year-old male Yorkshire terrier dog. The tumor was histologically composed of both hepatocellular carcinoma and cholangiocellular carcinoma components, and both elements were closely intermingled. Intraluminal mucin accumulation in cytokeratin-positive tubular/glandular structures was observed within the cholangiocellular carcinoma components and this feature was useful histological marker for a differential diagnosis between combined hepatocellular and cholangiocellular carcinoma and a pseudoglandular type of hepatocellular carcinoma. This primary hepatic tumor is extremely rare in dogs.     

Radiographic findings in dogs with naturally-occurring primary hypoadrenocorticism.

Survey radiographs often are obtained in dogs with primary hypoadrenocorticism in adrenal crisis as part of the routine evaluation of a critically ill dog. In this study, standardized methods of cardiac, pulmonary vasculature, and vena cava mensuration were used in 22 dogs with naturally-occurring primary hypoadrenocorticism, and the findings were compared with those in 22 breed-matched, clinically normal dogs. Most (81.8%) untreated dogs with primary hypoadrenocorticism had one or more radiographic abnormalities, including small size of the heart (45.5%), cranial lobar pulmonary artery (36.4%), caudal vena cava (54.5%), or liver (36.4%). Megaesophagus was not found in any of the dogs with hypoadrenocorticism, and therefore, compared to the other common radiographic findings, should be considered a rare finding.     

Assessment of survey radiography and comparison with x-ray computed tomography for detection of hyperfunctioning adrenocortical tumors in dogs

Results of abdominal survey radiography and x-ray computed tomography (CT) were compared in 13 dogs with hyperadrenocorticism histologically attributed to adrenocortical tumors. X-ray computed tomography enabled accurate localization of the tumor in all 13 dogs. Apart from 2 poorly demarcated irregular-shaped and mineralized carcinomas, there were no differences between adenoma (n = 3) and carcinoma (n = 10) on CT images. In 1 dog, invasion of the caudal vena cava by the tumor was suggested on CT images and was confirmed during surgery. Suspicion of adhesions between tumors of the right adrenal gland and the caudal vena cava on the basis of CT images was confirmed during surgery in only 2 of 6 dogs. Survey radiography allowed accurate localization of the tumor in 7 dogs (4 on the right side and 3 on the left). In 6 of these dogs, the tumor was visible as a well-demarcated soft tissue mass and, in the other dog, as a poorly demarcated mineralized mass. The smallest tumor visualized on survey radiographs had a diameter of 20 mm on CT images. Six tumors with diameter less than or equal to 20 mm were not visualized on survey radiographs. In 1 of these dogs, a mineralized nodule was found in the left adrenal region, without evidence of a mass. In a considerable number of cases, survey radiography can provide presurgical localization of adrenocortical tumors in dogs with hyperadrenocorticism; CT is redundant in these instances. In the absence of positive radiographic findings, CT is valuable for localization of adrenocortical tumors.     

A Comparison of Medullary Thyroid Carcinoma and Thyroid Adenocarcinoma in Dogs: A Retrospective Study of 38 Cases

The medical records of 38 dogs with thyroid neoplasia that were treated by surgical excision of the tumor, or had an incisional biopsy performed as a diagnostic procedure, were reviewed. Of the 38 dogs, 21 (55%) had resectable tumors, whereas 17 (45%) had an incisional biopsy as the tumors were nonresectable. All dogs had an initial diagnosis of thyroid carcinoma. The type of carcinoma was confirmed in 33 dogs by histological and immunohistochemical examination. Twelve dogs (36%) had medullary thyroid carcinoma, and 21 dogs (64%) had thyroid adenocarcinoma. Of the 12 dogs with medullary thyroid carcinoma, 10 (83%) had resectable tumors. Of the 10, three (30%) had at least a 1-year survival. None had radiographic evidence of metastasis at the time of surgery. Of the 21 dogs with thyroid adenocarcinoma, 11 (52%) had resectable tumors. Of the 11 dogs, five (45%) had at least a 1-year survival. Three dogs had radiographic evidence of metastasis at the time of surgery. Of 10 dogs with nonresectable thyroid adenocarcinoma, two dogs (20%) had at least a 1-year survival. In the dogs in this study, medullary thyroid carcinoma was more prevalent than previously reported. Most of the medullary thyroid carcinomas were well circumscribed and resectable. Medullary thyroid carcinoma may possess gross and histological characteristics of a less malignant nature when compared with other thyroid carcinomas.     

VERTEBRAL TUMORS IN THE DOG: A CLINICAL RADIOLOGIC, AND PATHOLOGIC STUDY OF 61 PRIMARY AND SECONDARY LESIONS

The clinical, radiographic, and histopathologic features of 26 primary and 35 secondary vertebral tumors of the dog with varying periods of clinical signs, possibly influenced by their being referred dogs, are presented. Pain without neurologic signs was the predominant initial sign with both primary and secondary tumors. However, by the time of hospital admission, most dogs had neurologic deficits. The time from pain onset to neurologic deficit ranged from two days to nine months. German Shepherd Dogs, Standard Poodles, and Labrador Retrievers were heavily represented; the average age was 7 years and there was a slight predominance of male dogs. Both primary and secondary tumors showed a destructive pattern, often with cortical destruction and adjacent disc space collapse. An associated paravertebral soft tissue mass was frequently present in the secondary tumors, 13 of 35 being secondary to intrapelvic tumors. Osteosarcomas were the most common primary tumor; the secondary tumor cell type varied. Most dogs were euthanized immediately upon histopathologic confirmation of the disease.     

Hypoglycemia associated with nonislet cell tumor in 13 dogs

Hypoglycemia associated with nonislet cell tumor was found in 13 dogs. In each dog, clinical signs were related directly to adrenergic and neuroglucopenic effects of hypoglycemia and included collapsing episodes, tremors, restlessness, weakness, and grand mal seizures that were responsive to glucose administration. Eight of the dogs had hepatocellular carcinoma; surgical resection of the tumor achieved remission of clinical signs in 3 of these dogs. Other hepatic tumors associated with hypoglycemia included leiomyosarcoma and hemangiosarcoma involving solitary lobes of the liver. Nonhepatic tumors included splenic hemangiosarcoma, diffuse metastatic melanoma, and salivary gland adenocarcinoma.     

RETROSPECTIVE ASSESSMENT OF THORACIC RADIOGRAPHIC FINDINGS IN METASTATIC CANINE HEMANGIOSARCOMA

Twenty-one dogs with histopathologically confirmed hemangiosarcoma were evaluated by thoracic radiography for metastatic disease. All dogs had histopathologic examinations of the lungs within two weeks of thoracic radiography. Fourteen dogs had histopathologic evidence of pulmonary hemangiosarcoma; metastatic disease was detected radiographically in eleven of these dogs. The most common radiographic pattern was that of poorly defined small coalescing nodules (8 dogs); other radiographic patterns included well-circumscribed nodules (3 dogs) and alveolar infiltrates secondary to hemorrhage (2 dogs). Differential diagnoses for diffuse, poorly defined, coalescing pulmonary opacities should include hemangiosarcoma in addition to edema, lymphoma, systemic mycoses, fibrosis, allergy, toxicosis, and carcinomas.     

Clinical and radiographic signs in primary and metastatic esophageal neoplasms of the dog.

Esophageal neoplasms were diagnosed in 8 of 49,229 dogs seen over the last 11 years at the Veterinary Medical Teaching Hospital of the University of California at Davis. The neoplasms were primary in 2 dogs and metastatic to the esophagus in 6 dogs, with thyroid carcinoma being the most common site of the primary tumor. The most common clinical signs were regurgitation, dysphagia, weight loss, development of neck masses, and respiratory difficulties. It was concluded that the clinical signs often can be misleading. The interpretation of survey radiographs, barium contrast studies, or fluoroscopic studies often provide the initial data base. The final diagnosis requires histologic examination. Retention of air in the esophagus (with or without esophageal displacement) and motor dysfunction (with or without gross morphologic changes) are the most important criteria for radiographic diagnosis.     

COMPUTED TOMOGRAPHIC IMAGING OF INFILTRATIVE LIPOMA IN 22 DOGS

Twenty two dogs with an infiltrative lipoma had computed tomographic (CT) images acquired to evaluate the extent of local disease. Ten dogs had undergone at least one cytoreductive surgical procedure (range = 1-3; median = 2) prior to imaging. Twenty dogs had measurable disease on CT images; 2 dogs had diffuse disease at a previous surgical site that could not be measured. Tumor volume (n = 20) ranged from 20 to 5,632 cm3 (median = 345 cm3; mean = 996 cm3). None of the dogs had evidence of bone involvement on the CT images; 2 of the 22 dogs had tumors that did not come into direct contact with osseous structures. All dogs with measurable disease had evidence of a fat opacity mass with variable degrees of muscle infiltration. Eleven of 22 dogs were given intravenous contrast medium prior to image acquisition and there was not evidence of enhancement of the infiltrative lipoma in any dog. Based on CT images, tumors were classified as well-defined in 9 dogs, moderately well-defined in 4, not well-defined in 3 and a mix of well-defined and not well-defined in 6 dogs. Tumors tended to be less well-defined in regions where the infiltrative lipoma interdigitated with normal body fat. It appears CT imaging allows adequate discrimination of tumor with the caveat that differentiation of normal fat from infiltrative lipoma can be problematic.     

Systemic Mastocytosis in 16 Dogs

The clinical and pathologic features of systemic mastocytosis in 16 dogs are reported. There was no apparent breed or sex predilection, and the median age at presentation was 9.5 years. In 14 of 16 cases there was a primary cutaneous mast cell tumor (MCT). When cutaneous tumor location was compared with previous reports, there was no association between location and systemic dissemination. The most common presenting signs associated with the cutaneous tumor were regional dissemination, edema, ulceration, and abscessation. They were present in 12 dogs (69%). Signs of systemic illness, including anorexia, vomiting, and diarrhea, were seen in eight dogs (50%). Other than the cutaneous tumors, the most consistent physical and radiographic abnormalities included lymphadenopathy, splenomegaly, and hepatomegaly. Eosinophilia and basophilia were seen in two and five dogs, respectively. Six dogs had increased numbers of mast cells in peripheral blood or buffy coat smears. Five of the nine dogs evaluated had increased numbers of mast cells in bone marrow aspirates. Bone marrow aspiration was superior to both peripheral blood and buffy coat smears in predicting mastocytosis. Coagulation abnormalities were seen in three of five dogs tested. Using a conventional histomorphologic grading system, 10 of 13 (77%) tumors were classified as Grade III or undifferentiated and were overrepresented when compared with previous reports of cutaneous MCTs. Eighty-eight percent of the dogs either died or were euthanatized because of their tumors. Organs commonly involved at necropsy included lymph nodes, spleen, liver, and bone marrow; four dogs had gastroduodenal ulcers.     

PRIMARY IRRADIATION OF CANINE INTRACRANIAL MASSES

Twenty-nine dogs received primary radiation therapy for intracranial lesions and clinical signs suggestive of neoplasia. Presumptive diagnosis and tumor categorization was based on computed tomographic or magnetic resonance images. Meningioma was the most likely tumor type in 22 dogs and glioma or choroid plexus tumors were tentatively identified in 4 and 3 dogs, respectively. Cobalt-60 radiation was delivered in 3 Gy fractions on a daily, Monday-through-Friday basis for a total dose of 48 Gy (16 fractions) in 28 dogs; one dog received 54 Gy. Two of 29 dogs died during treatment of signs suggestive of progressive tumor growth but were included in the overall evaluation of response to treatment. Median overall survival was 250 days (range 21-804). Mild acute radiation effects on normal tissue developed and did not influence outcome in any dog. Late radiation effects could not be evaluated in this study. No significant predictive indicators were identified from the clinical or imaging data. Radiation therapy is superior to medical treatment of brain tumors in dogs with steroids, is useful for tumors that are not currently operable and may be preferable to surgical resection in dogs if the mass appears infiltrative. However, 22/29 (76%) dogs died of recurrent progressive neuropathy suggestive of tumor regrowth or progression. Thus, alternative methods for delivery of radiation to dogs with brain tumors or novel combinations of therapy should continue to undergo evaluation.     

Immunohistochemical characterization of canine hyperplastic hepatic lesions and hepatocellular and biliary neoplasms with monoclonal antibody hepatocyte paraffin 1 and a monoclonal antibody to cytokeratin 7.

Immunostaining with monoclonal antibody (MoAb) hepatocyte paraffin 1 (Hep Par 1) and an MoAb to cytokeratin 7 (CK7) was performed on 105 formalin-fixed, paraffin-embedded canine hyperplastic and neoplastic hepatic lesions. Hep Par 1 was detected in 12/12 hyperplastic nodules, 17/17 hepatocellular adenomas, and 37/40 hepatocellular carcinomas. The staining was disseminated, granular, and cytoplasmic. This antibody did not react with normal or neoplastic biliary epithelium. Other hepatic tumors or tumors metastatic to the liver did not bind Hep Par 1 except one metastatic intestinal carcinoma. MoAb to CK 7 stained all hyperplastic biliary epithelium and benign cholangiocellular tumors (5/5) and 14/18 cholangiocellular carcinomas. One hepatocellular carcinoma had cells positive for both Hep Par 1 and CK 7. Liver was the only normal tissue tested that reacted with MoAb Hep Par 1. Only five nonhepatic tumors (one adrenocortical carcinoma, one interstitial cell tumor of the testis, one melanoma, and two salivary adenocarcinomas) of 277 tumors tested had focal/multifocal staining for Hep Par 1. Prolonged fixation did not alter the staining with Hep Par 1. We conclude that Hep Par 1 is a specific and sensitive marker for canine hepatocellular tumors and allows distinction between hepatocellular and biliary neoplasms.     

Magnetic resonance imaging and histological classification of intracranial meningiomas in 112 dogs

BACKGROUND: Intracranial meningiomas are the most common primary brain tumors in dogs. Classification of meningiomas by tumor grade and subtype has not been reported, and the value of magnetic resonance imaging (MRI) characteristics for predicting tumor subtype and grade has not been investigated. HYPOTHESIS: Canine intracranial meningiomas are a heterogenous group of tumors with differing histological subtypes and grades. Prediction of histopathological classification is possible based on MRI characteristics. ANIMALS: One hundred and twelve dogs with a histological diagnosis of intracranial meningioma. METHODS: Retrospective observational study. RESULTS: Meningiomas were overrepresented in the Golden Retriever and Boxer breeds with no sex predilection. The incidence of specific tumor grades was 56% benign (Grade I), 43% atypical (Grade II), and 1% malignant (Grade III). Grade I histological subtypes included meningothelial (43%), transitional (40%), microcystic (8%), psammomatous (6%), and angiomatous (3%). No statistically significant (P < .05) associations were found among tumor subtype or grade and any of the MRI features studied. CONCLUSIONS AND CLINICAL IMPORTANCE: Meningiomas in dogs differ from their counterparts in humans mainly in their higher incidence of atypical (Grade II) tumors observed. MRI characteristics do not allow for prediction of meningioma subtype or grade, emphasizing the necessity of histopathology for antemortem diagnosis. The higher incidence of atypical tumors in dogs may contribute to the poorer therapeutic response in dogs with meningiomas as compared with the response in humans with meningiomas.