GIST in Turner Syndrome

Gastrointestinal stromal tumors (GISTs) have three recognized molecular subtypes-KIT mutant, platelet-derived growth factor receptor alpha (PDGFRA) mutant, and wild-type. KIT and PDGFRA wild-type GISTs are seen in patients with the hereditary syndrome neurofibromatosis, but no such association has been established for Turner syndrome (TS), with only one prior case reported. We describe three further cases from a single UK sarcoma center.

Retrospective review of three women with TS diagnosed with GIST at our center, with clinicopathological and molecular data from routine diagnostic tumor and germline sequencing.

Patient 1 (53 years) had a gastric GIST with a rare primary KIT exon 17 mutation, managed surgically with surveillance alone. Patient 2 (64 years) had two synchronous, molecularly distinct gastric GISTs, each with a different PDGFRA mutation. Patient 3 (12 years) had a ruptured succinate dehydrogenase (SDH)-deficient gastric GIST with subsequent hepatic and mediastinal disease, in keeping with a Carney triad-spectrum phenotype.

Including the previously reported case, four GISTs have now been described in women with TS. Although case numbers are too few to establish an increased GIST susceptibility in TS, this is a hypothesis-generating observation that warrants further consideration and clarification of whether a genuine association exists.