Gastrointestinal stromal tumors of the esophagus: a clinicopathologic and molecular analysis of 27 cases

Abstract

Aims

Gastrointestinal stromal tumors (GISTs) may arise anywhere in the gastrointestinal tract, but are rare in the esophagus. We describe the clinical, pathologic, and molecular characteristics of 27 primary esophageal GISTs, the largest series to date.

Methods and Results

DNA was extracted and exons 9, 11, 13 and 17 of KIT, exons 12, 14 and 18 of PDGFRA and exon 15 of BRAF were amplified and sequenced. Esophageal GISTs occurred in 14 men and 13 women between 22 and 80 years of age (mean, 56 years). All 27 cases were immunohistochemically positive for KIT, and 92% and 47% co-expressed CD34 or smooth muscle actin, respectively. Fifteen (71% of analyzed cases) harbored KIT exon 11 mutations and one case each had a mutation in KIT exon 13 (K642E) or BRAF exon 15 (V600E). Long-term follow-up data (median, 96.5 months) were obtained for 20 cases; 2 patients had metastases at presentation and 7 had developed local recurrence and/or metastasis after surgery. A large tumor size (≥ 10 cm), high mitotic rate (> 5/5 mm²), presence of a deletion mutation in KIT exon 11 involving codons 557-558 and a positive microscopic margin were associated with recurrence and metastasis. The KIT mutations identified in esophageal GISTs are similar to those observed in gastric GISTs.

Conclusions

Complete surgical resection with clear margins is recommended, if technically feasible, and genotyping can help to improve diagnosis and further patient management in esophageal GIST.

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