Co-existence of gastrointestinal stromal tumors with other primary neoplasms.

BACKGROUND/AIMS: Gastrointestinal stromal tumors (GISTs) are the most common primary mesenchymal neoplasms of the tubular gastrointestinal tract (GI). Here, we present a series of 32 patients diagnosed with a primary neoplasm in addition to GIST, from six different institutions in Turkey. METHODOLOGY: In total, 200 patients with GIST were evaluated; 32 patients with both GISTs and other primary malignancies were identified. RESULTS: This study included 20 men and 12 women median age 66.5 years (range 43-78). GIST was incidentally found intra-operatively in 12 of the cases. All patients underwent surgery. Detection of the GIST was synchronous in 19 cases, metachronous in 7 cases and preceded the GIST diagnosis in 6 cases. The median time before follow-up evaluation ranged from 4 to 80 months. CONCLUSIONS: To our knowledge, no cases of GISTs co-existing with leiomyosarcoma of the spermatic cord and larynx tumors have been reported previously. The prevalence of malignancies in this subpopulation of GIST patients is significantly higher than the prevalence of malignancies in the healthy Turkish population. The high occurrence rate of additional primary malignancies in GIST patients has focused the attention of clinical oncologists on this problem, and may imply a common genetic mechanism for their etiology.