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Nasopharyngeal neoplasia is not common in horses. Tumours previously reported at this site include lymphosarcoma (Meschter and Allen, 1984; Lane, 1985), squamous cell carcinoma (Schuh, 1986) and undifferentiated adenocarcinoma (Baker, 1975). Equine mast cell tumours, both solitary and generalised, are usually confined to the skin and subcutis (Altera and Clark, 1970; Riley, Yovich and Howell, 1991). Epistaxis has several well recognised causes including exercise induced pulmonary haemorrhage (Mason et al., 1983), progressive ethmoid haematoma (Cook and Littlewort, 1974; Boles, 1979; Haynes, 1984 and Greet, 1985) and guttural pouch mycosis (Cook et al., 1968). Less common causes include ulcerative rhinitis, nasal polyps and turbinate bone necrosis (Cook and Littlewort, 1974). Nasal and nasopharyngeal tumours form an unusual cause of epistaxis.

Medical records of 55 dogs with a diagnosis of cutaneous mast cell tumour were reviewed. Twenty-seven of the dogs were treated with surgery plus deionized water and the remaining 28 with surgery alone. A survival analysis was performed to determine whether deionized water, as an adjunct to surgery for cutaneous mast cell tumour, affected survival time or time to tumour recurrence. Dogs in which mast cell tumour recurred had a significantly shorter survival time compared with dogs with no recurrence (P = 0.05), regardless of the method of treatment. A significant negative association between tumour recurrence and method of treatment (P = 0.0097) and clinical stage (P = 0.0223) was observed. Dogs treated with surgery and deionized water had a significantly shorter time to recurrence of their mast cell tumour (P = 0.0113). Based on these results, deionized water does not appear to be beneficial in prolonging survival time or time to tumour recurrence for dogs with cutaneous mast cell tumours.

Distilled water was studied as an hypoosmotic oncolysis agent to prevent mast cell tumour (MCT) recurrence following surgical excision. The results from 118 MCTs excised in 74 dogs were: surgery alone, a recurrence rate of 52.6 per cent (10/19); and surgery followed by distilled water injections into the wound, a 26.2 per cent (26/99) recurrence rate. All of 10 small MCTs (0.03 to 0.25 cm3) injected with distilled water in situ with no surgery, regressed. The present data suggest that distilled water should be considered as an adjunct to surgery for canine MCTs.

A FOUR-WEEK-OLD male boxer dog was seen with a firm, not painful, cutaneous mass in the left ventral and cranial abdomen region (Fig 1), which the breeder had first noticed 10 days before. The presence of the mass was not associated with any clinical signs. A diagnosis of mast cell tumour (MCT) was made, based on fine needle aspiration and cytological examination. A surgical excision was performed including a safety margin of 2 cm …

MAST cell tumours are commonly encountered in dogs (Dobson and others 2002) with the cutaneous form being the most common (Bostock 1986). The veterinary literature provides guidelines regarding both treatment and prognosis of cutaneous forms of the disease, which have been well reviewed (Dobson and Scase 2007). Mast cell tumours have been described in a wide range of other locations including the …

Summary A cat with weight loss, pyrexia and recurrent lethargy and depression was found to have pleural and peritoneal eosinophilic effusions, peripheral eosinophilia, eosinophilic lymphadenitis and a massively enlarged mesenteric lymph node. Visceral mast cell neoplasia was diagnosed after histopathological examination of a biopsy of the mass. Palliative chemotherapy was attempted unsuccessfully and the cat was euthanased.

In a controlled study, malignant murine P815 mastocytoma cells exposed in vitro to distilled and deionized water died as a result of progressive swelling, degranulation, and membrane rupture. A 90% mean cell death occurred when cells obtained directly from culture were exposed to deionized water for 2 minutes. Of 6 cryopreserved malignant murine cell lines, which included Cloudman S91 melanoma, CMT-93 rectum carcinoma, MMT-06052 mammary carcinoma, and S-180 Sarcoma, only P815 mastocytoma and YAC-1 lymphoma were significantly (P less than 0.05) affected by hypotonic shock; Cloudman S91 melanoma cells were the most resistant. Mastocytoma cells were selectively killed by hypotonic solution, and lymphoma cells were also killed by isotonic saline solution. Local mast cell tumor (MCT) recurrence and percentage survival were evaluated in 12 cats (21 MCT) and 54 dogs (85 MCT) subjected to surgery alone or local infiltration of deionized water as an adjunct to surgery. Of all 16 incompletely excised MCT in cats, there was no local recurrence following injection. Four mast cell tumors (2 cats) regressed after being injected in situ. In dogs with clinical stage-I MCT, local recurrence was detected in 50% (5/10), but with injection after incomplete excision, local MCT recurrence was significantly (P less than 0.05) less (6.6%, 1/15). Percentage recurrence was significantly (P less than 0.05) less and survival significantly greater when incompletely excised grade-II MCT were injected. Mean follow-up period after surgery in cats and dogs was 35 and 23.4 months, respectively.

Few cases of equine mast cell tumour have been reported in the literature. Most describe solitary nodular lesions of the skin and subcutaneous tissue that occasionally involve the underlying musculature (Altera and Clark 1970; Doran and Collins 1986; Nyrop et al. 1986; McEntee 1991). Lesions are generally confined to soft tissues and appear to be hyperplastic rather than neoplastic. One case involving local invasion of bone by a cutaneous neoplasm has been reported (Riley et al. 1991). The present report describes a case of hindlimb lameness due to a pathological fracture of the third phalanx resulting from a primary intraosseous mast cell tumour. This unique clinical presentation demonstrates that equine mast cell tumours are not always benign soft tissue lesions.

A 9-year old male German Shepherd Dog had a primary mast cell tumour in the ileocaecal valve. The dog had diarrhoea and weight loss and there was physical and radiographic evidence of an abdominal mass. A pedunculated mass was seen attached to the ileocaecal valve, and the adjoining lymph nodes were enlarged. The neoplastic cells were characterized by mature mast cells with typical granules replacing the intestinal wall and mesentery, which had metastasized to the lymph nodes, bone marrow, liver and lungs.

Eighty-three cutaneous mast cell tumors in the dog were classified morphologically into three grades. The neoplasms were excised surgically, and the dogs were followed for 1500 days. Comparison of morphologic grade of tumor with survival time revealed significant differences among the three groups (p < 0.00010). Comparison of sex and age (above and below ten years) with morphologic grade of tumor revealed no significant differences.

A cutaneous mast cell tumour associated with Darier's sign in a cat with multiple neoplasms is described. A 14-year-old cat with multiple neoplasms, one of which was a mast cell tumour developed marked subcutaneous oedema and erythema following palpation. The phenomenon is similar to Darier's sign described in people with mast cell tumours. The pathology of the Darier's sign is discussed.

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Follow-up studies have been conducted on 114 dogs from which mastocytomas were removed surgically, and the subsequent progress of each animal recorded. To date, 38 % of animals have died or been destroyed as a direct consequence of the neoplastic process and of these, 69 % had histologically poorly-differentiated (Grade 1), 18% intermediate (Grade 2), and 13% well-differentiated (Grade 3) tumours. The mean survival time of animals with Grade 3 tumours was 51 weeks, whilst for those which had Grade 2 or Grade 1 types it was 28 and 18 weeks respectively. Most dogs which survive for longer than 30 weeks post-operatively appear to be cured, and on this basis the apparent cure rate for animals with Grade 3 tumours was six times greater than that for animals with Grade 1, and twice as great as that for animals with Grade 2 tumours. Although the best method of obtaining an accurate prognosis is to submit the excised tumour for histological examination, it can be said on clinical grounds alone that if a mastocytoma has been present for more than 28 weeks before removal, the prognosis should be favourable, since 83% of animals with this history survived for more than 30 weeks post-operatively. Resume. On a poirsuivi des recherches complementaires sur 114 chiens dont on a excise les mastocytomes. Les progres subsequents de chaque animal ont ete enregistres. Jusqu'a present, 38% des animaux sont morts ou ont ete detruits comme consequence directe du processus neoplastique, 69% de ces chiens avaient des tumeurs histologiquement assez mal differenciees (Grade 1), 18% des tumeurs intermediaires (Grade 2), et 13% des tumeurs bien differenciees (Grade 3). La periode moyenne de survie des animaux avec des tumeurs du grade 3 etait de 51 semaines tandis que pour ceux ayant des tumeurs des grades 2 et 1, cette periode etait de 28 et de 18 semaines respectivement. La plupart des chiens qui survivent plus de 30 semaines apres l'operation, semblent gueris et sur ce principe, le taux apparent de guerison pour des animaux avec des tumeurs du grade 3 etait de 6 fois superieure a celui pour des animaux avec des tumeurs du grade 1 et deux fois aussi eleve que celui pour des animaux avec des tumeurs du grade 2. Bien que la meilleure methode pour obtenir un prognostic correct soit de faire subir un examen histologique a la tumeur excisee, on peut dire, pour raison clinique seulement, que si un masto-cytome a ete present pendant plus de 28 semaines avant d'etre enleve, le prognostic devrait etre favorable, vu que 83% des animaux avec ce genre d'histoire ont survecu pendant plus de 30 semaines apres l'operation. Zusammenfassung. Nachuntersuchungen wurden an 114 Hunden ausgefuhrt an denen Mas-tozytome chirurgisch beseitigt wurden und folgenden Fortschritt verzeichnete man von jedem Tier. Bis heute, krepierten oder wurden vernichtet 38% der Tiere als direkte Folge der bosartigen Gewebeneubildung und von diesen hatten 69% histologisch schlecht zu unterscheidende Tumors (Grad 1), 18% zwischenliegende Tumors (Grad 2), und 13% gut zu unterscheidende Tumors (Grad 3). Die Durchschnitts-Uberlebungszeit von Tieren mit Grad 3 Tumors war 51 Wochen, wahrend fur jene mit Grad 2 und Grad 1 Typ es jeweilig 28 und 18 Wochen waren. Die meisten Hunde, die langer als 30 Wochen postoperativ uberleben, scheinen geheilt zu sein und aud dieser Basis war der offenbare Heilungsprozentsatz fur Tiere mit Grad 3 Tumors sechs mal grosser als der fur Tiere mit Grad 1 Tumors und zwei mal so gross als der mit Grad 2 Tumors. Obwohl die beste Methode eine akkurate Prognose zu erlangen ist den herausgeschnittenen Tumor histologischer Untersuchung zu unterwerfen, kann man durch klinische Erfahrung allein behaupten, wenn ein Mastozytom mehr as 28 Wochen vor der Entfernung vorhanden war, dass die Prognose gunstig sein musste, da 83% von Tieren mit dieser Krankheitsgeschichte mehr als 30 Wochen nachoperativ uberlebten.

Summary. Standard ox heparin, dog mast cell tumour heparin, heparin monosulphuric acid and β-heparin from ox lung were compared with respect to anticoagulant effect on human, bovine and dog plasma in one-stage prothrombin, recalcification and thrombin systems, and on whole ox blood. Different values for the anti-coagulant activity of a certain heparin was observed when using the various assay methods, which is in conformity with the results of previous authors. In addition it was demonstrated that one and the same assay method for a certain heparin may give different results depending on the species of plasma used as clotting substrate.

A 10-year-old Golden Labrador developed a well-differentiated lymphoid cell leucaemia during chemotherapy for a malignant mast cell tumour. Similar treatment had been carried out 2 years previously for another mast cell tumour. The possibility of an association between the anti-neoplastic chemotherapy and the lymphatic leucaemia is discussed.

SUMMARY An Airedale Terrier with a gastric carcinoma in the antrum and liver metastases, and a Poodle with a mast cell tumour and gastric ulceration and perforation were studied. The acidity of the gastric juice in these two dogs was compared with that in healthy experimental dogs with Heidenhain pouches after maximal gastric stimulation with 6 μ g/kg of pentagastrin. The possible ‘diagnostic value’ of stomach acidity is discussed against the background of some hypotheses of normal gastric physiology in canine and human medicine.

MAST cells of dogs are said not to contain 5-hydroxytryptamine1–4. Furthermore, this substance has not been found in neoplasms of these cells in dogs5. An instance of a dog mast cell tumour is reported here, however, in which there was histochemical evidence of the presence of 5-hydroxytryptamine.

1. Mast-cell tumour P815 cells oxidize [(35)S]cyst(e)ine to (35)SO(4) (2-). 2. Addition of cysteinesulphinate or sulphite decreases the formation of (35)SO(4) (2-); at the same time [(35)S]cysteinesulphinate or (35)SO(3) (2-) accumulates. 3. Extracts of P815 cells form sulphite from cysteinesulphinate and 2-oxoglutarate. The K(m) for cysteinesulphinate is 6.35mm and that for 2-oxoglutarate is 0.165mm. 4. Extracts oxidize sulphite to sulphate. 5. No formation of hydrogen sulphide from cyst(e)ine was detectable. 6. It is concluded that P815 cells oxidize cyst(e)ine to sulphate solely via cysteinesulphinate and sulphite. 7. The concentration of the enzymes catalysing this sequence is unaltered by several variations in the conditions of growth.

cytological grading for mast cell tumours (MCTs) would be highly desirable, allowing to select the most appropriate therapeutic intervention prior to surgery. This study evaluates the applicability on fine-needle aspirations (FNAs) of the novel Kiupel grading system, based on number of mitoses, multinucleated cells, bizarre nuclei and presence of karyomegaly. Fifty consecutive cases with pre-operative cytological diagnosis were included. In cytological specimens, approximately 1000 cells were evaluated, and the histological grade was assessed on the corresponding resected specimens. On cytology, the above parameters were significantly different between histologically low-grade and high-grade tumours (P

Dissertação de Mestrado Integrado em Medicina Veterinária Os mastocitomas representam cerca de 11 a 27% de todas as neoplasias cutâneas malignas do cão. Devido à sua prevalência e comportamento biológico variável, ao custo da terapêutica e ao potencial stress emocional para os tutores, é importante realizar um prognóstico preciso dos mastocitomas cutâneos e selecionar corretamente a abordagem terapêutica mais apropriada. Vários fatores clínicos podem influenciar o curso da doença, no entanto, o fator de prognóstico mais importante é a gradação histológica. As mutações no c-kit e as alterações da expressão do KIT são conhecidas como indicadores de prognóstico negativo em mastocitomas cutâneos caninos. Além disso, animais portadores de mastocitomas com mutações no c-kit ou padrões de expressão anormais do KIT são potenciais candidatos à terapêutica alvo com inibidores dos recetores tirosina quinase (IRTQ). O principal objetivo deste estudo foi selecionar o melhor IRTQ para cada caso, com base no padrão de expressão do KIT. Um objetivo adicional foi a identificação e avaliação de fatores influenciadores de prognóstico, através de associações estatísticas e da análise de sobrevivência. Os 42 casos de animais com mastocitomas investigados foram, inicialmente, distribuídos por sexo, idade, raça, localização, tipo de lesão e grau histológico do tumor e, ainda, padrão de expressão do KIT. A idade do animal mostrou associação significativa com o grau histológico (p=0,0495) e a localização tumoral com o padrão de expressão do KIT (p=0,0271). Além disso, o risco de desenvolvimento de tumores com padrões do KIT atípicos foi superior nos animais com idades superiores a 8 anos, lesões múltiplas e tumores de alto grau histológico. Como bons indicadores influenciadores de prognóstico identificaram-se a idade no momento do diagnóstico (p=0,01) e o grau histológico do tumor (p=0,002). O risco de morte, relacionada com o mastocitoma, foi superior nos animais com tumores com padrões do KIT atípicos. As variáveis que apresentaram impacto significativo no tempo de sobrevivência foram a idade, o grau histológico, o tratamento quimioterápico e o tratamento com IRTQ. Foram, ainda, obtidos melhores resultados nas fêmeas e nos mastocitomas com padrão de expressão 1. Apesar das limitações do estudo, os resultados obtidos podem contribuir para o estabelecimento de um prognóstico e para a escolha da terapêutica a implementar em casos de mastocitoma cutâneo canino. ABSTRACT - KIT expression in canine mast cell tumour: tyrosine kinase inhibitors selection - Mast cell tumours (MCT) are the most frequently diagnosed malignant skin neoplasm in dogs, representing up to 27% of all canine cutaneous neoplasms. Due to their prevalence and variable biologic behavior, the cost of therapeutics, and the potential emotional stress to owners, it is important to accurately prognosticate cutaneous mast cell tumours and to correctly select the most appropriate therapeutic approach. There are varied clinical factors that may influence the outcome; however, accurate histologic grading remains a cornerstone of MCT prognostication. Mutations in c-kit and altered expression of KIT have been shown to be negative prognostic indicators for canine cutaneous mast cell tumours. Furthermore, those mast cell tumours that have c-kit mutations or abnormal KIT expression are potential candidates for targeted therapy with tyrosine kinase inhibitors. The main goal of this study was to select the best tyrosine kinase inhibitor for each KIT expression pattern. An additional goal was the identification and evaluation of prognosis influencing factors, through statistical associations and survival analysis. The 42 mastocytomas investigated were initially distributed by sex, age, race, location, type of lesion, histological grade and KIT expression. The animal age showed a significant association with the histological grade (p = 0.0495) and the tumor location with the KIT expression (p = 0.0271). In addition, the risk of developing tumors with atypical KIT patterns was higher in animals aged over 8 years, with multiple lesions and tumors of high histological grade. The age at diagnosis (p = 0.01) and the histological grade of the tumor (p = 0.002) showed to be good prognostic indicators. The risk of death related to the mast cell tumour was higher in animals with tumors with atypical KIT patterns. The variables that had a significant impact on survival time were age, histological grade, chemotherapeutic treatment and treatment with tyrosine kinase inhibitors. Better results were also obtained in females and mast cells tumours with expression pattern 1. Lastly, despite the limitations of the study, the results obtained may be useful in establishing a prognosis and in the therapeutic choice in cases of canine cutaneous mast cell tumour. N/A