Rare and unknown canine systemic mastocytosis: clinical and laboratory features of an aberrant c-Kit mutation neoplasia / A rara e desconhecida mastocitose sistêmica canina: características clínicas e laboratoriais de uma neoplasia aberrante na mutação c-Kit

Systemic mastocytosis (SM) pathology is extremely rare in canine practice, with insufficient reported data. The knowledge of the clinical behavior of this pathology is scarce. In human medicine, SM has been widely investigated, being defined as a rare hematopoietic disorder by the World Health Organization (2016), within the type of myeloproliferative neoplasms. Herein, we describe a systemic mastocytosis case in a Portuguese Serra-da-Estrela dog, where a cutaneous grade III/high-grade MCT was also diagnosed. The clinical decline of the animal and owner's insistence throughout anamnesis that the dog was markedly different after the cytologic exam performed in another clinic, along with both severe eosinophilia and hepatomegaly, led to the clinical suspicion of SM. The animal passed away 7 days later. Post-morteminvestigation confirmed SM pathology, and a deletion of 15 base pairs change on c-Kit gene exon 11 was identified. Contemplating the low number of cases described in the literature, this publication aims to disclose clinical and laboratory features of rare and poorly described canine SM, taking into consideration human outcomes described in the literature.(AU)

A patologia da mastocitose sistêmica (SM) é extremamente rara na prática clínica canina, com escassos casos descritos na literatura científica. O conhecimento do comportamento clínico desta patologia é mínimo. Na medicina humana, a SM tem sido amplamente investigada, sendo definida como uma doença hematopoiética rara pela Organização Mundial da Saúde (2016), dentro do tipo de neoplasias mieloproliferativas. Descrevemos aqui um caso de mastocitose sistêmica num cão Serra-da-Estrela português, diagnosticado também com um mastocitoma cutâneo grau III / alto grau. O declínio clínico do animal e a insistência do proprietário durante a anamnese de que o cão estava marcadamente diferente após o exame citológico realizado em outra clínica, juntamente com eosinofilia e hepatomegalia graves, levantaram a suspeita clínica de SM. O animal faleceu 7 dias depois. A investigação post-mortem confirmou a patologia SM, e o estudo molecular revelou uma deleção de 15 pares de bases no exon 11 do gene c-Kit. Contemplando o baixo número de casos descritos na literatura, o objetivo desta publicação é divulgar características clínicas e laboratoriais de SM canina, levando em consideração informações clínicas descritas em humanos.(AU)

Analysis of c-kit Gene Mutation and Prognostic Factors of GISTs in the Small and the Large Bowel

PURPOSE: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors which arise anywhere in the tubular GI tract. The prognosis for GISTs that develop in the small and the large bowel is worse than it is for those that develop at other sites. We examined the significance of c-kit mutation as an independent prognostic factor for GISTs. METHODS: The hospital records of 27 patients with GISTs in the small and the large bowel who were seen from January 1991 to December 2001 at the Department of Surgery, The Catholic University School of Medicine, were reviewed. c-kit mutation was measured by using the PCR and DNA sequencing. RESULTS: Mutations in exon 11 were found in 5 cases (83.3%), exon 9 in 1 case (16.7%), and no mutations were noted in exon 13 and exon 17. All mutations in exon 11 were found in codon 560-570. c-kit mutation was observed more frequently in high-risk patients, and there was a significant difference between c-kit mutation and the survival rate (P=0.048). CONCLUSIONS: We think that codon 550~560 in exon 11 of the c-kit gene is a hotspot of mutation, but c-kit mutation is uncertain as an independent prognostic factor for GISTs.

Analysis of c-kit Mutation of Gastrointestinal Stromal Tumors

PURPOSE: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumor, and express the KIT protein. Previous studies have reported KIT phosphorylation to be the principal biological event in the tumoriogenesis of GIST, which is generally evoked by the conformational mutation of KIT receptors. The aim of this study was to evaluate the frequency and category of c-kit mutations and their prognostic relevance. METHODS: The frequency and category of the c-kit mutations and the correlation between clinical outcome and the c-kit mutations were analyzed and the significance of the c-kit mutations examined as independent prognostic factors in 84 cases of GIST. The c-kit mutations were measured by polymerase chain reaction and DNA sequencing, using an ABI 3700 sequencer. RESULTS: c-kit mutations were noted in 14 of the 84 cases (16.7%) of GIST. Mutations in exon 11 were found in 11 cases (78.6%), exon 9 in 2 (14.3%) and exon 13 in 1 (7.1%), but no mutation was noted in exon 17. Of the mutations in exon 11, missense mutations were observed in 9 cases and frameshift mutations in 2. Among the 14 cases with c-kit mutations, 1 (7.1%) was found in a very low risk patient, 4 (28.6%) in intermediate risk patients and 9 (64.3%) in high risk patients. The c-kit mutations were observed more frequently in high risk patients (P=0.0366). However, there was no significant difference between the c-kit mutations and the survival rate. CONCLUSION: These results suggest that kit mutations might have a pathogenetic role in GIST, 550~560 in exon 11 of c-kit gene is the conserving area of mutation and c-kit mutations are uncertain as prognostic factors in GIST. However, further study will be required.

Analysis of c-kit Mutation of Gastrointestinal Stromal Tumors

PURPOSE: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumor, and express the KIT protein. Previous studies have reported KIT phosphorylation to be the principal biological event in the tumoriogenesis of GIST, which is generally evoked by the conformational mutation of KIT receptors. The aim of this study was to evaluate the frequency and category of c-kit mutations and their prognostic relevance. METHODS: The frequency and category of the c-kit mutations and the correlation between clinical outcome and the c-kit mutations were analyzed and the significance of the c-kit mutations examined as independent prognostic factors in 84 cases of GIST. The c-kit mutations were measured by polymerase chain reaction and DNA sequencing, using an ABI 3700 sequencer. RESULTS: c-kit mutations were noted in 14 of the 84 cases (16.7%) of GIST. Mutations in exon 11 were found in 11 cases (78.6%), exon 9 in 2 (14.3%) and exon 13 in 1 (7.1%), but no mutation was noted in exon 17. Of the mutations in exon 11, missense mutations were observed in 9 cases and frameshift mutations in 2. Among the 14 cases with c-kit mutations, 1 (7.1%) was found in a very low risk patient, 4 (28.6%) in intermediate risk patients and 9 (64.3%) in high risk patients. The c-kit mutations were observed more frequently in high risk patients (P=0.0366). However, there was no significant difference between the c-kit mutations and the survival rate. CONCLUSION: These results suggest that kit mutations might have a pathogenetic role in GIST, 550~560 in exon 11 of c-kit gene is the conserving area of mutation and c-kit mutations are uncertain as prognostic factors in GIST. However, further study will be required.