Alimentary neoplasia in geriatric dogs and cats.

Lymphomas, carcinomas, leiomyomas, and stromal tumors are the most common tumors found in the canine and feline gastrointestinal tract. Endoscopic and surgical biopsies are often the mainstays of diagnosis, although ultrasound is playing an increasingly greater role. Small cell lymphocytic lymphoma of the feline intestines poses a special diagnostic dilemma and may require immunohistochemistry as well as polymerase chain reaction to distinguish it from lymphocytic-plasmacytic enteritis. This article will focus on the more common neoplastic problems of the esophagus and gastrointestinal tract (GIT) of geriatric dogs and cats.

Cutaneous MCTs: associations with spay/neuter status, breed, body size, and phylogenetic cluster.

Certain breeds are known to be overrepresented among mast cell tumor (MCT) patients, but other risk factors have not been evaluated. This study presents results from a case-control study of 252 dogs with grade 2 or grade 3 cutaneous MCT. Increased risk for MCT development was found in spayed females (adjusted odds ratio [OR], 4.11), boxers (adjusted OR, 6.09), Labrador retrievers (adjusted OR, 3.95), pugs (adjusted OR, 3.17), golden retrievers (adjusted OR, 2.12), the mastiff and terrier phylogenetic cluster (adjusted OR, 3.19), and breeds classified as large (adjusted OR, 2.10) or giant (adjusted OR, 5.44). Additional studies are needed to evaluate the role of these and other potential risk factors in MCT development.

Mast cells and canine mast cell tumours. A review.

This article reviews the literature on mast cells and tumours derived from mast cells in the dog. Mast cells play a central role in inflammatory and immune reactions. Mast cells, normal and neoplastic, contain and release important biologically active substances: heparin, histamine, eosinophilic chemotactic factor and proteolytic enzymes. Mast cell tumours occur in the dog, particularly in the boxer and related breeds, in the skin and less frequently in the intestines. Cytology usually provides an accurate diagnosis, but histological examination adds further information concerning the histologic grade and the completeness of surgical therapy. Cutaneous mast cell tumours should be regarded as potentially malignant and therefore be removed widely (3 cm. margin). Local recurrence, regional and distant metastases together with paraneoplastic disorders may cause the death of the pet. Histologic grading (2 or 3 grades) and clinical staging together with kinetic parameters and breed (boxers have relatively benign tumours) are important prognostic parameters. Based on prognostic criteria, surgical treatment should be completed with adjuvant radiotherapy, corticosteroids and eventually with combined chemotherapy. A novel, promising therapy is the application of the receptor kinase inhibitor. The study of the pathogenesis of mast cell tumours received new impetus by the finding of mutations, deletions and duplications, in exons 11 and 12 of the C-kit oncogene. Further study of physiological and oncological aspects of mast cells are favoured by the availability of mast cells isolated from spontaneous mast cell tumours and of cultured cell lines.

Recurrence rates and sites for grade II canine cutaneous mast cell tumors following complete surgical excision.

A retrospective study was performed on 31 dogs with completely excised, grade II, cutaneous mast cell tumors in order to determine recurrence rates and sites. Distant tumor recurrence developed in 22% of dogs, and local tumor recurrence developed in 11% of dogs; however, the vast majority of these animals were incompletely staged initially. Complete surgical excision of grade II mast cell tumors was associated with effective local control in 89% of these dogs. Therefore, adjuvant radiation therapy might not be indicated in the majority of dogs with complete surgical excision.

Diagnostic criteria and classification of mastocytosis: a consensus proposal.

The term 'mastocytosis' denotes a heterogeneous group of disorders characterized by abnormal growth and accumulation of mast cells (MC) in one or more organ systems. Over the last 20 years, there has been an evolution in accepted classification systems for this disease. In light of such developments and novel useful markers, it seems appropriate now to re-evaluate and update the classification of mastocytosis. Here, we propose criteria to delineate categories of mastocytosis together with an updated consensus classification system. In this proposal, the diagnosis cutaneous mastocytosis (CM) is based on typical clinical and histological skin lesions and absence of definitive signs (criteria) of systemic involvement. Most patients with CM are children and present with maculopapular cutaneous mastocytosis (=urticaria pigmentosa, UP). Other less frequent forms of CM are diffuse cutaneous mastocytosis (DCM) and mastocytoma of skin. Systemic mastocytosis (SM) is commonly seen in adults and defined by multifocal histological lesions in the bone marrow (affected almost invariably) or other extracutaneous organs (major criteria) together with cytological and biochemical signs (minor criteria) of systemic disease (SM-criteria). SM is further divided into the following categories: indolent systemic mastocytosis (ISM), SM with an associated clonal hematologic non-mast cell lineage disease (AHNMD), aggressive systemic mastocytosis (ASM), and mast cell leukemia (MCL). Patients with ISM usually have maculopapular skin lesions and a good prognosis. In the group with associated hematologic disease, the AHNMD should be classified according to FAB/WHO criteria. ASM is characterized by impaired organ-function due to infiltration of the bone marrow, liver, spleen, GI-tract, or skeletal system, by pathologic MC. MCL is a 'high-grade' leukemic disease defined by increased numbers of MC in bone marrow smears (>or=20%) and peripheral blood, absence of skin lesions, multiorgan failure, and a short survival. In typical cases, circulating MC amount to >or=10% of leukocytes (classical form of MCL). Mast cell sarcoma is a unifocal tumor that consists of atypical MC and shows a destructive growth without (primary) systemic involvement. This high-grade malignant MC disease has to be distinguished from a localized benign mastocytoma in either extracutaneous organs (=extracutaneous mastocytoma) or skin. Depending on the clinical course of mastocytosis and development of an AHNMD, patients can shift from one category of MC disease into another. In all categories, mediator-related symptoms may occur and may represent a serious clinical problem. All categories of mastocytosis should be distinctively separated from reactive MC hyperplasia, MC activation syndromes, and a more or less pronounced increase in MC in myelogenous malignancies other than mastocytosis. Criteria proposed in this article should be helpful in this regard.

Pediatric mastocytosis.

Pediatric mastocytosis presents with heterogeneous cutaneous lesions and symptoms that are caused by increased numbers of tissue mast cells. In contrast with adult patients with mastocytosis, the course of pediatric patients is usually transient. Therefore, it has long been speculated that pediatric and adult mastocytosis may be based on different pathogenetic mechanisms. Indeed, new genetic findings now indicate differences in the pathogenesis. Adult patients usually express activating mutations of the growth factor receptor c-kit. Most children lack these mutations but sometimes carry other inactivating mutations of c-kit. Only children with progressive mastocytosis seem to express the activating mutations seen in adults. Causal treatment is not yet available, but H1 and H2 antihistamines may provide relief of symptoms. It is important to counsel patients and their parents carefully to avoid triggers that induce systemic mast cell degranulation.

Visceral mast cell tumors in dogs: 10 cases (1982-1997).

OBJECTIVE: To characterize the clinical features of visceral mast cell tumors (MCT) without associated cutaneous involvement in dogs. DESIGN: Retrospective study. ANIMALS: 10 dogs with histologically confirmed MCT without associated cutaneous lesions. PROCEDURE: Information on signalment, clinical signs, laboratory examinations, and time from first admission to death was obtained from the medical record of each dog. RESULTS: Purebred male dogs of miniature breeds appeared to have a higher prevalence of visceral MCT. Clinical signs included anorexia, lethargy, vomiting, and diarrhea. Anemia (n = 7), hypoproteinemia (5), and mastocythemia (5) were detected. Treatments, including glucocorticoids, were not successful. Primary sites of tumors were the gastrointestinal tract (n = 6) and the spleen or liver (1); the primary site was not confirmed in the remaining 3 dogs. In 7 dogs, tumors were categorized as grade II or III, on the basis of histologic findings. The prognoses were poor, and all dogs died within 2 months after first admission. CONCLUSIONS AND CLINICAL RELEVANCE: Visceral MCT is uncommon in dogs, and the prognosis is extremely poor. Biological behavior and drug susceptibility of visceral MCT may be different from cutaneous MCT. The lack of specific clinical signs may result in delay of a definitive diagnosis. The rapid progression of clinical signs and difficulty in diagnosis contributes to a short survival time.

Systemic, metastatic, eu- and heterotope tumours of the heart in necropsied dogs.

10,090 dissections of dogs exhibited 2631 neoplastic processes of which 309 involved the heart in the form of eu- and heteropic tumours. The most common primary and/or secondary heart tumour type was hemangiosarcoma (n = 187), followed by paraganglioma (n = 46), carcinoma (n = 33), malignant lymphoma (n = 12), thyroid heart base tumour (n = 9), melanoma (n = 7), mast cell tumour (n = 3) and blastoma (n = 2). The tumour diagnoses were immunohistochemically proved by various antibodies to cytokeratins, vimentin, GFAP, NSE, von Willebrand factor, CD3, CD45RA, S100, thyroglobulin as well as histochemically with argyrophilic, Fontana-Masson and heterochromatic reactions. The odds ratio (OR) for breed and tumour prevalences were determined: German shepherds showed the highest OR for hemangiosarcomas and boxers for paragangliomas.

The occurrence of mast cell tumors in young Shar-Peis.

During 1991 and 1992, 802 case submissions diagnosed as canine mast cell tumors were submitted to the Athens Veterinary Diagnostic Laboratory. Eighteen of these submissions were from dogs of the Shar-Pei breed. Of these 18 cases, 5 occurred in Shar-Peis less than 2 years of age, 4 of these were poorly differentiated, and 4 out of 5 occurred in the inguinal or preputial area. Three mast cell tumors (grade I) occurred in Boxer/Boxer cross dogs, and 2 tumors (grade II) occurred in Cocker Spaniels younger than 2 years of age. Of the 23,315 histopathology submissions, only 164 were from Shar-Peis and 57 of these dogs were under 2 years of age.

[Mast cell tumors in dogs--diagnosis and therapy of a malignant skin tumor]. / Der Mastzelltumor des Hundes--Diagnose und Therapie eines malignen Hauttumors.

The high prevalence of mast cell tumors in dogs and their variable presentation make this neoplasia a diagnostic and therapeutic challenge for the small animal practitioner. Classification of the tumor according to histologic grade and clinical stage of the disease is important for therapy and prognosis. Surgical excision and chemotherapy are discussed for individual tumor grades and stages.

Cutaneous neoplasia in 340 cats.

A total of 340 cases of cutaneous neoplasia were diagnosed in 340 of 3,564 cats that were examined by biopsy or necropsy during a 41-month period from January 1, 1986 through May 31, 1989. Eighteen types of tumor occurred, but four types comprised 77% of the cases. These were basal cell tumor, 89 cases (26%, mean age 10.3); mast cell tumor, 72 cases (21%, mean age 8.6); squamous cell carcinoma, 52 cases (15%, mean age 11.6); and fibrosarcoma, 50 cases (15%, mean age 10.2). For each of these four types of tumors, peak number of cases occurred in cats older than 10 years. Mast cell tumor was the only tumor diagnosed in cats younger than 1 year. The head was the most common site for basal cell tumors, mast cell tumors, and squamous cell carcinomas. The legs were the most common location of fibrosarcomas. Siamese cats had approximately three times as many mast cell tumors as statistically expected, but only one-fourth as many squamous cell carcinomas. Breed predilection for other skin tumors was not apparent. Sex predilection was not detected for any skin tumor.

Skin neoplasms of dogs in Sydney.

In a survey of dogs in Sydney, mastocytomas (16.1%) and histiocytomas (14.0%) were the most common in a total of 1,000 skin neoplasms. The basal cell and appendage group provided 25.5% of the neoplasms. The prevalence of the various neoplasms, the age of affected dogs, the proportion in the sexes, the common sites of occurrence and prevalence in the different breeds were broadly similar to findings in surveys in other countries, except that in the Syndeny dogs there was a greater prevalence of histiocytomas and haemangiopericytomas, a more common occurrence of histiocytomas in mature dogs, an occurrence of histiocytomas in similar numbers on the head, trunk and limbs, and a remarkably common development of squamous cell carcinomas in Dalmatians.

Canine mast cell tumors.

Despite the fact that the mast cell tumor is a common neoplasm of the dog, we still have only a meager understanding of its etiology and biologic behavior. Many of the published recommendations for treatment are based on opinion rather than facts derived from careful studies and should be viewed with some skepticism. Because of the infrequent occurrence of this tumor in man, only a limited amount of help can be expected from human oncologists; therefore, burden of responsibility for progress in predicting behavior and developing treatment effective for canine mast cell tumors must fall on the shoulders of the veterinary profession.

[General facts on mastocytoma in the dog. Apropos of the first Tunisian case]. / Données générales sur le mastocytome du chien. A propos du premier cas tunisien.

After anatomo-pathologic, épidemiologic and etiopathogenic description of canine Mast-cell tumor, the authors insist on the importance of this neoplasm in comparative pathology. Such animal model observation can be eventually used both in cancer Research and in allergo-dermatology.