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)

Establishment of patient derived xenograft model of high-grade mucinous carcinoma peritonei accompanied with signet ring cells and identification of biological characteristics / 中华肿瘤杂志

Objective@#To establish the patient derived xenograft (PDX) model of pseudomyxoma peritonei (PMP), and identify the key characteristics of tumor biology of this model, in order to provide a reliable model for studying the pathological mechanisms and new therapeutic strategies of PMP.@*Methods@#PMP tumor tissue was obtained from surgery and cut into pieces after washing. Then tumor pieces were implanted subcutaneously in BAL B/c-nu mice for 6 stable passages. In the 7th passage, tumor tissue was implanted orthotopically into abdomen. Subcutaneous tumor and orthotopic tumor were then homogenized to make tumor cell suspension, implanted into abdomen of 10 BAL B/c-nu mice through midline laparotomy, 100 μl for each. The key experimental parameters including body weight changes in the observation period, experimental peritoneal cancer index (ePCI) score at the autopsy, histopathological and immunohistochemical characteristics, and gene expression profiles by high-throughput whole-genome exon sequencing were detected and recorded.@*Results@#The successful rate of established orthotopic PDX model of human PMP was 100% (10/10). The animals showed smooth body weight increases after tumor inoculation until day 27, then the body weight began to decrease steadily. Widespread tumor dissemination of PMP tumor through the whole abdomen was found by autopsy, including the diaphragm, liver, spleen, stomach, kidney, parietal peritoneum, bowel and mesenterium. Gelatinous ascites was also observed in abdominopelvic cavity. The ePCI score ranged from 5 to 9, with a 8 of median ePCI. Histopathological studies showed peritoneal mucinous carcinomatosis accompanied with signet ring cells (PMCA-S), obvious tumor cell atypia and parenchymal invasion.Immunohistochemistry showed the expressions of MUC1, MUC2, MUC5AC, CEA, CA199, CK20, CDX-2 and Ki-67 were positive, MUC6, CK7 and p53 were negative. Whole-exome sequencing identified that the most significant genetic alteration is the exon10 missense mutation c. 1621A>C of KIT gene, the mutation abundance was 89.7%.@*Conclusion@#PDX model of PMCA-S is successfully established, which displays the characters of high-degree malignancy, high proliferation and strong aggressiveness.

Molecular and Clinicopathological Features of Gastrointestinal Stromal Tumors in Vietnamese Patients

BACKGROUND: Gastrointestinal stromal tumors (GISTs) are the most frequent mesenchymal neoplasms of the gastrointestinal tract. Management of GIST patients is currently based on clinicopathological features and associated genetic changes. However, the detailed characteristics and molecular genetic features of GISTs have not yet been described in the Vietnamese population.METHODS: We first identified 155 patients with primary GIST who underwent surgery with primary curative intent between 2011 and 2014 at University Medical Center at Ho Chi Minh City, Vietnam. We evaluated the clinicopathological features and immunohistochemical reactivity to p53 and Ki-67 in these patients. Additionally, KIT genotyping was performed in 100 cases.RESULTS: The largest proportion of GISTs was classified as high-risk (43.2%). Of the 155 GISTs, 52 (33.5%) were positive for Ki-67, and 58 (37.4%) were positive for p53. The expression of Ki-67 and p53 were correlated with mitotic rate, tumor size, risk assessment, and tumor stage. Out of 100 GIST cases, KIT mutation was found in 68%, of which 62 (91.2%) were found in exon 11, two (2.9%) in exon 9, and four (5.8%) in exon 17. No mutation in exon 13 was identified. Additionally, KIT mutations did not correlate with any clinicopathological features.CONCLUSIONS: The expression of Ki-67 and p53 were associated with high-risk tumors. Mutations in exon 11 were the most commonly found, followed by exon 17 and exon 9. Additionally, KIT mutation status was not correlated with any recognized clinicopathological features.

Two different KIT mutations may lead to different responses to imatinib in metastatic gastrointestinal stromal tumor

No abstract available.

Amelanotic Acral Melanoma Associated with KIT Mutation and Vitiligo

Amelanotic acral melanoma is rare and difficult to diagnose, both clinically and pathologically. KIT mutations are frequently found in acral melanomas and are considered a risk factor for poor prognosis. The presence of vitiligo in melanoma has been reported, and KIT is thought to be partly responsible for the dysfunction and loss of melanocytes observed in vitiligo. We report a case of amelanotic subungual melanoma with multiple metastases that was associated with KIT mutation and vitiligo. An 85-year-old man presented with a 3-year history of a tender erythematous ulcerated tumor on the left third fingertip and developed hypopigmented patches on the face and trunk. Histopathological examination of the ulcerative tumor showed aggregates of tumor cells that were pleomorphic epithelioid cells. Immunohistochemical staining of the tumor cells was positive for S100, HMB45, and c-Kit. Histopathological findings from the hypopigmented patch on the face were consistent with vitiligo. Mutation analysis showed a KIT mutation in exon 17 (Y823D). The patient had metastasis to the brain, liver, bone, and both lungs. The patient refused chemotherapy, and died 3 months after the first visit.

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.

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.