Adult Gastrointestinal Stromal Tumors Research Articles

Clinical and molecular characteristics of pediatric gastrointestinal stromal tumors (GISTs)

8537 Background: GISTs are the most common mesenchymal tumors of the gastrointestinal tract in adults and are characterized by c-KIT expression (CD117). The natural history and molecular characteristics of these tumors in children are virtually unknown. Objective: Describe clinical characteristics, treatment, outcome, and molecular features of pediatric GISTs. Methods: Retrospective study of 6 patients with GIST seen at HSC over an 11-year period. DNA was extracted from tumor and amplified by exon 11 specific primers to determine mutational status. Analysis of other coding sequences of the gene is being performed and will be presented at the meeting Results: The characteristics of the patients are depicted in the table.The median age at diagnosis was 13.6 years (range 6.9–14.8 years).Four patients were female. Iron deficiency anaemia secondary to gastrointestinal (GI) hemorrhage was a presenting feature in all patients. The common primary site was the stomach. Five patients presented with localized disease; one had disseminated disease to omentum. Two patients had evidence of Carney's triad. All tumors were diffusely positive for CD117 and CD34. None of the three samples available for molecular analysis revealed an exon 11 c-KIT mutation. All of the tumors were surgically resected and none of the pts received chemotherapy. Disease recurred in 1 pt, 2 were lost to follow-up, and 4 remain alive.Conclusion: GISTs should be considered in the differential diagnosis of pediatric pts presenting with anaemia secondary to a GI hemorrhage. GISTs in the pediatric population preferentially occur in the second decade of life, arise in the stomach, and do not exhibit an exon 11 c- KIT mutation. The latter findings suggest that pediatric GISTs may have biological differences compared to adult GISTs. Multicenter trials are needed to better elucidate the natural history, molecular phenotype, and therapies for these pts. No significant financial relationships to disclose.

Clinical and molecular characteristics of pediatric gastrointestinal stromal tumors (GISTs)

8537 Background: GISTs are the most common mesenchymal tumors of the gastrointestinal tract in adults and are characterized by c-KIT expression (CD117). The natural history and molecular characteristics of these tumors in children are virtually unknown. Objective: Describe clinical characteristics, treatment, outcome, and molecular features of pediatric GISTs. Methods: Retrospective study of 6 patients with GIST seen at HSC over an 11-year period. DNA was extracted from tumor and amplified by exon 11 specific primers to determine mutational status. Analysis of other coding sequences of the gene is being performed and will be presented at the meeting Results: The characteristics of the patients are depicted in the table.The median age at diagnosis was 13.6 years (range 6.9–14.8 years).Four patients were female. Iron deficiency anaemia secondary to gastrointestinal (GI) hemorrhage was a presenting feature in all patients. The common primary site was the stomach. Five patients presented with localized disease; one had disseminated disease to omentum. Two patients had evidence of Carney's triad. All tumors were diffusely positive for CD117 and CD34. None of the three samples available for molecular analysis revealed an exon 11 c-KIT mutation. All of the tumors were surgically resected and none of the pts received chemotherapy. Disease recurred in 1 pt, 2 were lost to follow-up, and 4 remain alive.Conclusion: GISTs should be considered in the differential diagnosis of pediatric pts presenting with anaemia secondary to a GI hemorrhage. GISTs in the pediatric population preferentially occur in the second decade of life, arise in the stomach, and do not exhibit an exon 11 c- KIT mutation. The latter findings suggest that pediatric GISTs may have biological differences compared to adult GISTs. Multicenter trials are needed to better elucidate the natural history, molecular phenotype, and therapies for these pts. No significant financial relationships to disclose.