Cutaneous mast cell tumor in a captive Bush dog (Speothos venaticus): pathological and immunophenotypical aspects - case report / Mastocitoma cutâneo em um cachorro-do-mato vinagre (Speothos venaticus) de cativeiro: aspectos patológicos e imunofenotípicos - relato de caso

A senile male captive bush dog (Speothos venaticus) presented a small perianal cutaneous nodule. Histologically, there was an ulcerated round cell tumor composed of well differentiated mast cells with abundant intracytoplasmic purple Giemsa-positive granules, with a diffuse eosinophilic infiltrate. Immunohistochemistry revealed that 30% of the neoplastic cells were positive for Kit in the cytoplasm and cell membrane, and all neoplastic cells were negative for MAC and CD3. Less than 10% of the neoplastic cells were positive for Ki67. At necropsy other primary tumors were identified in this animal, including an intestinal adenoma, an adrenal cortex adenoma and a testicular interstitial cell tumor.(AU)

Um cachorro-vinagre (Speothos venaticus) apresentou um nódulo cutâneo pequeno na região perianal. Histologicamente havia neoplasia cutânea de células redondas e ulcerada, constituída por mastócitos bem diferenciados, com abundantes grânulos citoplasmáticos metacromáticos na coloração de Giemsa e infiltrado eosinofílico difuso. A imuno-histoquímica demonstrou que 30% das células neoplásicas eram positivas para a proteína Kit no citoplasma e na membrana celular. As células foram negativas para MAC e CD3. Menos de 10% das células neoplásicas foram positivas para Ki67. Durante a necropsia, foram identificados outros tumores primários, como adenoma intestinal, adenoma cortical da adrenal e tumor de células intersticiais do testículo.(AU)

Use of different fixation times and application of two immunohistochemical methods for detection of KIT and Ki67 proteins in canine cutaneous mast cell tumors / Utilização de diferentes tempos de fixação e métodos imuno-histoquímicos na detecção das proteínas KIT e Ki67 em mastocitomas cutâneos caninos

Due to the high prevalence of mast cell tumors (MCTs) in the diagnostic routine, several factors, especially prognostic, have been sought to determine the biological behavior of these neoplasms. Immunohistochemistry (IHC) is one of the main tools utilized to biologically differentiate more aggressive tumors from less aggressive ones. However, some immunostainings are influenced by formalin fixation, interfering with the results. This is both a retrospective and prospective study of MCTs diagnosed in laboratory routine. A total of 25 samples, without knowledge about fixation time, were analyzed in the retrospective study, whereas 12 samples, with known fixation times, were assessed in the prospective study. Two histologic grading systems (Patnaik and Kiupel), special staining of toluidine blue, and IHC for KIT and Ki67 proteins were applied in both studies. Additionally, two amplification systems (biotinylated and non-biotinylated) for Ki67 protein and counting of the argyrophilic nucleolar organizing regions (AgNOR method) were tested in the prospective study. In the retrospective study, greater agreement between the evaluating pathologists was observed when the Kiupel system was used. IHC staining for KIT protein was effective in both studies, regardless of fixation time. IHC staining for Ki67 protein was highly sensitive to formaldehyde, and staining failure was observed in 56% of the cases in the retrospective study. In the prospective study, samples fixed for longer than 24 hours showed a reduction in the number of stained cells (altering the determination of the cell growth fraction) or showed absence of IHC staining in both amplification systems. The use of the AgNOR method to evaluate the rate of cell proliferation may be an alternative when the fixation time of the neoplasm is unknown or longer than 24 hours.(AU)

Devido a alta prevalência dos mastocitomas cutâneos caninos (MCCs) na rotina diagnóstica, vários fatores, especialmente fatores prognósticos, têm sido buscados para auxiliar na determinação do comportamento biológico desse neoplasma. A imuno-histoquímica é uma das principais ferramentas empregadas para diferenciar tumores biologicamente mais agressivos de tumores menos agressivos. Entretanto, algumas imunomarcações sofrem influência pela fixação em formol, interferindo nos resultados. Este estudo compreendeu avaliar através de uma etapa retrospectiva e uma etapa prospectiva casos de MCCs diagnosticados na rotina laboratorial. Um total de 25 amostras, sem conhecimento do tempo de fixação, foi analisado no estudo retrospectivo e 12 amostras, com tempos de fixação conhecidos, no estudo prospectivo. Foram aplicados nos dois estudos, dois sistemas de graduação histológica (Patnaik e Kiupel), a coloração especial de azul de toluidina e a imuno-histoquímica para as proteínas KIT e Ki67. Adicionalmente, no estudo prospectivo, foram testados dois sistemas de amplificação (biotinilado e não biotinilado) para a proteína Ki67 e a técnica de AgNOR (contagem das regiões organizadoras nucleolares argirofílicas). Na etapa retrospectiva, observou-se uma maior concordância entre os patologistas avaliadores quando o sistema Kiupel foi utilizado. A imunomarcação para KIT se manteve eficaz em ambos os estudos, independentemente do tempo de fixação. A imunomarcação para o Ki67 mostrou-se altamente sensível ao tempo de fixação em formol, sendo observada falha na imunomarcação em 56% dos casos do estudo retrospectivo. No estudo prospectivo, constatou-se que amostras fixadas por mais de 24 horas em formol apresentaram redução na quantidade de células imunomarcadas (alterando a determinação da fração de crescimento celular) ou apresentaram ausência de imunomarcação em ambos os sistemas de amplificação. A utilização do método AgNOR, para avaliar a taxa de proliferação celular, pode ser uma alternativa quando o tempo de fixação do neoplasma for desconhecido ou superior a 24 horas.(AU)

Grau de malignidade do mastocitoma cutâneo canino quanto a localização segundo as classificações de Patnaik et al. (1984) e Kiupel et al. (2011) / Degree of malignancy of the canine cutaneous mast cell tumor as forlocation according to the classifications of Patnaik et al. (1984) and Kiupel et al. (2011)

Objetivou-se com o presente trabalho coletar dados epidemiológicos relacionados com o mastocitoma canino, além de verificar se há relação entre sua malignidade e localização e, por fim, comparar os métodos de classificação histopatológica segundo Patnaik et al. (1984) e segundo Kiupel et al. (2011). Informações foram coletadas da ficha clínica de 55 cães e 60 fragmentos de pele com mastocitomas foram avaliados histologicamente. Verificou-se que a ocorrência de mastocitoma cutâneo não é influenciada pelo sexo e raça, porém cães sem raça definida e boxers são mais acometidos. Não há uma faixa etária susceptível bem definida, sendo o mastocitoma mais frequente em cães de 8 a 9 anos de idade. A região mais acometida foi a inguinal (50%) e a cabeça a região que apresentou mastocitomas com maior malignidade. Utilizando a classificação de Patnaik et al. (1984) houve diferença significativa entre as classificações histopatológicas de mastocitoma avaliadas por diferentes patologistas, o que não ocorreu utilizando a classificação de Kiupel et al. (2011). Pode-se dizer então que a classificação de Kiupel et al. (2011) gera menor divergência nos diagnósticos, demonstrando-se um método simples e eficaz para a avaliação histopatológica de mastocitoma.

The aim of the present study is to collect epidemiological data related to the canine mastocytoma, to check if there is relationbetween malignancy and its location and, finally, to compare the methods of histopathological classification according to Patnaiket al. (1984) and Kiupel et al. (2011). Informations were collected from the clinical record of 55 dogs and 60 fragments of skinwith a diagnosis of mast cell tumor were evaluated histologically. It was found that the occurrence of cutaneous mast cell tumorsis not influenced by gender and race, but dogs without defined breed and boxers are most affected. There is not a well-definedsusceptible age, but the most mast cell tumors in dogs often 8 to 9 years old. The highest affected region was inguinal (50%) andhead proved a region with higher malignancy. Using the classification Patnaik et al. (1984) there was a significant difference betweenthe histopathological ratings mastocytoma evaluated by different pathologists, which did not occur using the classification Kiupel etal. (2011). It can be said then that the classification Kiupel et al. (2011) generates less divergence in the diagnosis, demonstratinga simple and effective method for histopathological evaluation of mastocytoma.

Mastocitosis cutánea: revisión de 10 años de experiencia en el Servicio de Dermatología del Hospital General de Niños Pedro de Elizalde / Cutaneous mastocytosis: 10-years experience review at the Dermatology Department, Hospital General de Niños Pedro de Elizalde

Introducción. La mastocitosis representa un espectro de trastornos clínicos con un fenotipo común correspondiente a una hiperplasia de los mastocitos tisulares. Objetivo. Presentar la experiencia del Servicio de Dermatología del Hospital General de Niños Pedro de Elizalde en mastocitosis cutánea en los últimos 10 años. Diseño. Estudio retrospectivo y descriptivo, de corte transversal. Material y método. Se revisaron los archivos histológicos correspondientes al período que va de marzo de 1999 a marzo de 2099 del Servicio de Dermatología del Hospital General de Niños Pedro de Elizalde. Se consideraron como variables de estudio la edad al momento de la consulta, sexo, presencia de antecedentes personales y familiares, tipo clínico, localización, presencia de síntomas al examen físico, así como hallazos patológicos en los estudios complementarios. Los resultados se expresaron en promedios y porcentajes. Resultados. Presentamos 49 casos con diagnóstico clínico e histológico de mastocitosis cutánea; 33 pacientes (67,3%) de sexo masculino y 16 (32,7%) de sexo femenino. En cuanto al tipo clínico de mastocitosis, se encontraron 36 casos de urticaria pigmentosa (73,4%), 6 casos de mastocitoma solitario (12,2%), 5 casos de telangiectasia macularis eruptiva perstans (10,2%) y 2 casos donde coexistía mastocitoma solitario y urticaria pigmentosa (4%). No se encontraron casos de mastocitosis cutánea difusa. Las lesiones se distribuyen en tronco 25 casos (51%), en tronco y miembros 17 casos (34,6%), en cabeza, tronco y miembros 3 casos (6,1%), en miembros 3 casos (6,1%), en cabeza y tronco un caso (2,04%). Conclusión. En nuestra casuística, la manifestación clínica más frecuente fue la urticaria pigmentosa, similar a lo señalado en la bibliografía. Encontramos, a diferencia de lo publicado en la literatura, un predominio de sexo masculino y un alto porcentaje (10,2%) de pacientes pediátricos con la forma de telangiectasia macularis eruptiva perstans.

IntroductionMastocytosis represents a spectrum of clinical disorders with a common phenotype correspondingto hyperplasia of mast cells on tissues.ObjectiveTo present the experience of the Department of Dermatology, Hospital General de Niños Pedro deElizalde in cutaneous mastocytosis during the past 10 years.DesignRetrospective and descriptive, cross sectional study.Material and methodsHistological records were reviewed for the period March 1999-March 2009 at the Department ofDermatology, Hospital General de Niños Pedro de Elizalde.The variables considered were: age at time of consultation, gender, presence of personal andfamily history, clinical type, location, presence of symptoms by physical examination andabnormal findings on complementary studies.The results were expressed as averages and percentages.ResultsForty nine patients with clinical and histological diagnosis of cutaneous mastocytosis arepresented, 33 of them were male (67.3%) and 16 were female (32.7%).As regards to the clinical type of mastocytosis, 36 patients presented urticaria pigmentosa(73.4%), 6 had solitary mastocytoma (12.2%), 5 presented telagiectasia macularis eruptivaperstans (10.2%) and 2 patients presented solitary mastocytoma combined with urticariapigmentosa (4%). Diffuse cutaneous mastocytosis was not found.Twenty five patients had lesions distributed on the trunk (51%), trunk and limbs on 17 (34.6%),head, trunk and limbs 3 patients (6.1%), on limbs only 3 patients (6.1%), while head and trunktogether were affected on 1 patient (2.04%).ConclusionIn our caseload, the most frequent clinical manifestation was urticaria pigmentosa, similar tofindings in the literature.As opposed to published data we found predominance in males, and a high incidence (10.2%)of pediatric patients with telangiectasia macularis eruptiva perstans.

Cutaneous mastocytosis in Thai children.

BACKGROUND: Mastocytosis is a disorder of mast cells proliferation within various organs, most commonly in the skin. The disease more commonly appears during infancy than adult. OBJECTIVE: To characterize the clinical features, response to therapy and prognosis of cutaneous mastocytosis in children. MATERIAL AND METHOD: A retrospective study of cutaneous mastocytosis was performed at Queen Sirikit National Institute of Child Health during January 1994 to December 2007.All cases were confirmed by histological diagnosis. RESULTS: There were a total of 50 patients. The male to female ratio was 1:1.2. Age at onset of lesions ranged from birth to 7 years. Forty-seven patients (94%) developed skin lesions within the first year of ife. There were 45 cases (90%) of urticaria pigmentosa, 3 cases (6%) of mastocytoma and 2 cases (4%) of diffuse cutaneous mastocytosis. None of the patient had a family history of cutaneous mastocytosis. Most of the children were healthy, except the one who had germ cell ovarian tumor Skin biopsies were performed in all cases and revealed mast cells infiltrate in the dermis. Treatment included oral antihistamine in all cases. Oral mast cell stabilizers were given in 6 patients (12%) and topical corticosteroids in 15 patients (30%). Four patients (8%) were treated with oral prednisolone. The skin lesions resolved only in 1 patient (2%) at age 7.8 years, the others still had skin lesions without systemic symptoms. CONCLUSION: Cutaneous mastocytosis is a benign disease in children without systemic involvement.

Mastocitoma solitario: Presentación de un caso en el adulto / Solitary mastocytoma: Presentation in an adult

El objetivo de esta publicación es mostrar un caso de mastocitoma solitario en la vejez, debido a la rareza de su aparición en tal etapa. Sus diagnósticos diferenciales y la involución total de la lesión con el uso de apósitos hidrocoloides, son comentados.

We present a case of a solitary mastocytoma in a man 86 years old who developped the lesion on the inferior lip. The interest of the case is the rarity of the presentation in an adult, which presents others differential diagnostics, and the success of the treatment with hidrocolloid dressings.