PURPOSE: @entity674 ( @entity674 ) is the most common mesenchymal malignancy of the gastrointestinal tract. GISTs may coexist with different types of @entity5 , either synchronous or metachronous. The frequency of this association and the spectrum of @entity5 involved have not been sufficiently analyzed; most of publications describe a single case report and rare case series. In the absence of definitive data, it could be interesting to compare the frequency of the occurrence of @entity674 and second @entity5 in literature. METHODS: A review of all case series that reported the frequency of the occurrence of @entity674 and synchronous second @entity5 were considered. RESULTS: Six retrospective case series were considered, including 440 @entity674 @entity1 ; of these, there were 64 (14.5  %) @entity1 with other synchronous second @entity5 . Median age was 67  years, median @entity674 size was 3.91  cm (range 3.0-4.79  cm), and all cases (100.0  %) were @entity2467 and @entity2280 positive. According to the risk categories, 35.2  % of @entity1 had a very low risk, 24.0  % a low risk, 27.6  % an intermediate risk, and 13.2  % a high risk. CONCLUSIONS: Regarding the occurrence of GISTs and synchronous second @entity5 , we can consider it as more common than it has been considered. Differently, concerning the topic of the incidence of second @entity5 (SPMs) and metachronous second @entity5 in pre- @entity2213 and after- @entity2213 era, we can consider it as a clinically relevant topic; according to the present knowledge, the main cause for the increased incidence of SPMs in the @entity2213 era is explained by the increased survival of @entity1 with metastatic GISTs and therefore more time available to develop SPMs.

The Occurrence of XXXX and Second Malignancies.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity5 :: ('MESH:D009369', 'Disease') :: ['primary malignancies', 'cancer', 'neoplasms', 'malignancies'] @entity2467 :: ('3815', 'Gene') :: ['CD117'] @entity2280 :: ('947', 'Gene') :: ['CD34'] @entity2213 :: ('MESH:C097613', 'Chemical') :: ['imatinib'] @entity674 :: ('MESH:D046152', 'Disease') :: ['GIST', 'Gastrointestinal stromal tumor']
@entity674 :: (MESH:D046152,Disease) :: ['Gastrointestinal Stromal Tumors']
