Gastrointestinal stromal tumors and other malignancies: a case series.

Purpose: This paper aims to review the clinical and pathological features of gastrointestinal stromal tumors (GISTs) occurring with other malignancies.

Methods: A retrospective analysis has been worked out considering all consecutive patients with GISTs referred to our institution between February 2002 and June 2010. We analyzed the relationship among clinical and biological characteristics of the disease and the occurrence of second cancer.

Results: Twenty-four patients with GIST have been recorded: in eight cases (33.3%), a second cancer was diagnosed and was synchronous in six patients. In the subgroup of synchronous malignancy, GISTs (four of stomach and one of ileum) were discovered during surgery for other gastrointestinal cancers, whereas one case (arising in the duodenum) was diagnosed during the staging procedure for another primary cancer. In the subgroup of GISTs associated with a second cancer, median age at diagnosis was higher (69 vs. 65 years), patients were more frequently male (62.5% vs. 43.8%), GISTs were smaller (median size 3 vs. 8 cm), and spindle cell histology was less frequent (25% vs. 69.2%); all cases were CD117-positive. Other characteristics were similar in the two subgroups, with the exception of risk category, with low or very low cases higher (75% vs. 20%), even if not statistically, in the subgroup of cases associated with other cancers.

Conclusions: Because of the limited number of cases, we cannot exclude an incidental relationship, but this association should be considered, especially during disease staging or surgery for other gastrointestinal cancer, when lesions in other intestinal tracts are detected. Larger studies are needed.