Analysis Of Clinicopathologic Characteristics And Prognosis Of Multiple Gastrointestinal Stromal Tumors

Objectives:Multiple gastrointestinal stromal tumors(GISTs)are rare,except for in cases of Carney’s syndrome,pediatric GISTs,type 1 neurofibronatosis-associated GISTs,and familial GISTs.The aim of this study was to investigate the clinicopathologic characteristics and prognosis of multiple GISTs.Methods:Between May 2003 and June 2018,patients who underwent surgery for multiple GISTs were retrospectively analyzed.Mutations for 4 exons of KIT and 2 exons of PDGFRA were detected.The recurrence-free survival(RFS)and overall survival(OS)rates were estimated using the Kaplan-Meier method.Results:A total of 20 patients with multiple GISTs were enrolled.There were 11 females and 9 males with a median age of 59 years(range:37-80 years).Of these,16 were sporadic cases and 4 were associated with GIST syndromes(2 cases of Carney triad and 2 cases of neurofibromatosis type 1(NF1)).Multiple GISTs were found in the stomach in 10 patients,small intestine in 5 patients,stomach and small intestine in 3 patients,rectum in 1 patient,and mesentery in 1 patient.The most common presentation were gastrointestinal bleeding.Approximately 80%of the tumors were<5 cm,and 57.4%had<5 mitoses per 50 high power fields(HPFs).The rate of positivity was 98.1%for CD117,87.0%for CD34,and 31.5%for SMA.Two patients with GISTs associated with the Camey triad harbored no KIT or platelet-derived growth factor A(PDGFRA)mutations.Different KIT mutations among individual tumors were detected in nine patients.During the median follow-up period of 66 months(range:3-183 months),four patients developed liver or abdominal metastases,three of whom died from the tumors.The RFS and OS rates at 5 years were 66%and 77%,respectively.Conclusion:Multiple GISTs may occur as sporadic tumors,or as an additional component of specific syndromes(eg Carney triad and NF1)that display different clinicopathologic characteristics based on their particular underlying mechanisms.The overall prognosis is favorable and tumor multiplicity does not necessarily imply higher malignancy.