Guhyun Kang1, Yuna Kang2, Kyung-Hee Kim3, Sang Yun Ha4, Jung Yeon Kim1, Young Mog Shim5, Michael C Heinrich6, Kyoung-Mee Kim4, Christopher L Corless7. 1. Department of Pathology, Sanggye Paik Hospital, Inje University, Seoul, Korea. 2. Department of Pathology, Dongsan Medical Center, Keimyung University, Daegu, Korea. 3. Department of Pathology, Chungnam National University School of Medicine, Daejeon, Korea. 4. Department of Pathology and Translational Genomics, Samsung Medical Center, Sungkyunkwan University, Seoul, Korea. 5. Department of Thoracic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. 6. Division of Hematology and Medical Oncology, VA Portland Health Care System and Oregon Health and Science University, Portland, OR, USA. 7. Department of Pathology and Knight Cancer Institute, Oregon Health & Science University, Portland, OR, USA.
Abstract
AIMS: Gastrointestinal stromal tumours (GISTs) may arise anywhere in the gastrointestinal tract, but are rare in the oesophagus. We describe the clinical, pathological and molecular characteristics of 27 primary oesophageal 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. Oesophageal GISTs occurred in 14 men and 13 women aged between 22 and 80 years (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 analysed cases) harboured 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; two patients had metastases at presentation and seven had developed local recurrence and/or metastasis after surgery. A large tumour 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 oesophageal 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 oesophageal GIST.
AIMS: Gastrointestinal stromal tumours (GISTs) may arise anywhere in the gastrointestinal tract, but are rare in the oesophagus. We describe the clinical, pathological and molecular characteristics of 27 primary oesophageal 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. Oesophageal GISTs occurred in 14 men and 13 women aged between 22 and 80 years (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 analysed cases) harboured 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; two patients had metastases at presentation and seven had developed local recurrence and/or metastasis after surgery. A large tumour 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 oesophageal 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 oesophageal GIST.