Pediatric gastrointestinal stromal tumors: a commentary on the value of referral clinics for rare pediatric tumors
Gastrointestinal stromal tumors (GIST) are mesenchymal neoplasms of the gastrointestinal tract that originates from intestinal pacemaker cells, also known as interstitial cells of Cajal (1). Most cases are seen in adults between the 4th and 6th decade of life. Children and adolescents are rarely affected, and only 1.4% to 2.7% of all GISTs occur in this population (2). The most common clinical scenario in younger patients is the diagnosis of a gastric GIST that usually occurs in adolescent females (3). Pediatric GIST has unique clinical, biological and genetic features that are distinct from adulthood GIST (4). While most GISTs in adults have an activating mutation of the KIT or platelet-derived growth factor receptor (PDGFR) proto-oncogenes, this is only present in only 10% of pediatric GISTs. GISTs that lack KIT or PDGFR mutations are considered wild-type GISTs (WT-GISTs) (5). Several receptor tyrosine kinase inhibitors such as Imatinib have proven effective in treating GIST that shows KIT or PDGFR mutations (6). Treatment of GIST is based on surgical resection with negative margins, since it is resistant to chemotherapy and radiation. The addition of receptor tyrosine kinase inhibitors is recommended for patients with KIT or PDGFR mutations.