Clinicopathological and genetic features of mutant gastrointestinal stromal tumors with rare lymph node metastasis and literature review

Gastrointestinal stromal tumors (GISTs) are the common neoplasms of the gastrointestinal (GI) tract. Liver and peritoneum are the most metastatic sites, but lymph node metastasis is relatively rare. In this study, 6 cases of GISTs with lymph node metastasis were studied and reviewed the literature. The patients (5 males and 1 female) ranged in age from 48 to 75 years (median, 66 y). Primary tumors developed on intestinal (5 cases) and stomach (1 case), and then 5 cases presented synchronous metastases including liver and/or peritoneal cavity. Intraperitoneal lymph node metastases were detected in all cases. On immunohistochemistry (IHC), tumors cell and metastases were diffusely positive for KIT, DOG1, SDHB, most positive for CD34 and focal for SMA. And exon 11 mutation was detected in all cases. 1 patient died of synchronous intrahepatic biliary adenocarcinoma, and other cases received imatinib mesylate had no signs of tumor recurrence (follow-up about 1-30 months). In conclusion, our results suggest that clinicopathological features of GISTs with rare lymph node metastasis is similar to adult mutated GISTs. High grade GISTs with liver metastasis and/or peritoneal cavity spread, especially intestinal GISTs, should keep on high alert for lymph node metastasis. Patients with lymph node metastatic GISTs usually show exon 11 mutation of KIT gene and targeted therapy can get a very good control of tumor progression.