OBJECTIVE
The purpose of this article is to describe the imaging and
clinicopathologic characteristics of esophageal gastrointestinal stromal
tumors (GISTs) and to emphasize the features that differentiate esophageal
GISTs from esophageal leiomyomas.
MATERIALS AND METHODS
A pathology database search identified all surgically resected or
biopsied esophageal GISTs, esophageal leiomyomas, and esophageal
leiomyosarcomas from 1994 to 2012. Esophageal GISTs were included only if
imaging studies (including CT, fluoroscopic, or 18F-FDG PET/CT
scans) and clinical data were available.
RESULTS
Nineteen esophageal mesenchymal tumors were identified, including
eight esophageal GISTs (42%), 10 esophageal leiomyomas
(53%), and one esophageal leiomyosarcoma (5%). Four patients
(50%) with esophageal GIST had symptoms, including dysphagia in
three (38%), cough in one (13%), and chest pain in one
(13%). One esophageal GIST appeared on barium study as a smooth
submucosal mass. All esophageal GISTs appeared on CT as well-marginated
predominantly distal lesions, isoattenuating to muscle, that moderately
enhanced after IV contrast agent administration. Compared with esophageal
leiomyomas, esophageal GISTs tended to be more distal, larger, and more
heterogeneous and showed greater IV enhancement on CT. All esophageal GISTs
showed marked avidity (mean maximum standardized uptake value, 16) on PET
scans. All esophageal GISTs were positive for c-KIT (a cell-surface
transmembrane tyrosine kinase also known as CD117) and CD34. On
histopathology, six esophageal GISTs (75%) were of the spindle
pattern and two (25%) were of a mixed spindle and epithelioid
pattern. Five esophageal GISTs had exon 11 mutations (with imatinib
sensitivity). Clinical outcome correlated with treatment strategy (resection
plus adjuvant therapy or resection alone) rather than risk
stratification.
CONCLUSION
Esophageal GISTs are unusual but clinically important mesenchymal
neoplasms. Although esophageal GISTs and esophageal leiomyomas had
overlapping imaging features, esophageal GISTs tended to be more distal,
larger, more heterogeneous, and more enhancing on CT and were markedly FDG
avid on PET. Given their malignant potential, esophageal GISTs should be
included in the differential diagnosis of intramural esophageal
neoplasms.