Abstract 4683: Coexistence incidence and clinicopathologic characteristics of gastrointestinal stromal tumors with gastrointestinal carcinoma

Abstract

Abstract Objective Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumors of the digestive tract. The coexistence with other gastrointestinal carcinoma is unique. The aim of this study was to investigate the coexistence of GIST with other primary gastrointestinal carcinoma and its clinicalpathologic features. Methods 113 patients had been diagnosed as GIST in three local hospitals from 2002 to 2008. The surgical specimens were analyzed with an immunohistochemical panel that included staining for CD117, CD34, SMA and Ki-67. Results 16.8 % of (19 of 113) patients with GIST were co-diagnosed as gastrointestinal carcinoma. The average age at diagnosis was 57 years (range, 43 to 66), two years older than that of the patients only with GIST (range, 43 to 71). The patients with the coexistence of GIST and gastrointestinal carcinoma included 11 males and 8 females. The male-to -female ratio was 1.38:1, which is higher than that of the patients of GIST without the carcinoma (1.24:1). 26.3% GIST with the carcinoma was found in the esophagus (5 of 19) and 73.7% in the stomach (14 of 19) and non in the intestine. In contrast, only 5.3% GIST without the carcinoma was found in the esophagus (5 of 94) which was less incidence in the esophagus than that of coexistence of GIST and the carcinoma (P < 0.05), 84.0% in the stomach and 10.6% in the intestine, which higher incidence in the intestine than that of coexistence of GIST and the carcinamo (P < 0.05). The mean diameter of 19 GISTs with the carcinoma was 1.91 cm (range, 0.6 to 3.8 cm) smaller than that of 94 GISTs without the carcinoma (5.42 ± 6.17 cm, p < 0.05). 15.8% of the patients with coexistences of GIST and the carcinoma showed lower dysplasia, whereas 41.5 % of GIST patients without the carcinoma had the dysplasia and 33.0 % was malignant (p < 0.05). The average mitotic count in GIST with the carcinoma was 0.74/high-power field (HPF) (range, 0-4/HPF), and much less than that (3.78/HPF) of GIST without the carcinoma (range, 0 to 53/HPF, P < 0.05). The average proliferative index (positive number of Ki-67/HPF) of GIST with the carcinoma was 7.16/HPF (range 0 to 22) and less than that (19) of GIST without the carcinoma (range, 0 to 107). Conclusion 16.8% of GIST was co-diagnosed with gastrointestinal carcinoma. More coexistence of GIST and the carcinoma occurred in the esophagus. The GIST with the carcinoma was less proliferative and aggressive than the GIST without the Carcinoma. [Key words] gastrointestinal stromal tumor; pathology; carcinoma Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4683.