[Disappearance of a gastric lesion following modified FOLFOX6 chemotherapy in a patient with metastatic colorectal cancer: a case report and literature review].

A 48-year-old man with colorectal cancer and right inguinal lymph node metastasis had previously undergone radiotherapy and chemotherapy (uracil/tegafur/leucovorin) after a colostomy in another hospital before being referred to us. Esophagogastroduodenoscopy (EGD) revealed the presence of a gastric metastatic lesion. After three courses of treatment with a modified regimen of leucovorin plus 5-fluorouracil plus oxaliplatin-6 (mFOLFOX6), EGD revealed that the gastric lesion had disappeared; computed tomography revealed that the size of the primary tumor and inguinal lymph node metastasis were markedly reduced. Subsequently, he underwent rectal resection of the primary tumor and continued treatment with mFOLFOX6 in combination with bevacizumab. We reviewed 29 similar cases from the literature, and determined that surgical resection of the tumor and appropriate chemotherapy can lead to long-term survival for patients with gastric metastases from colorectal cancer. Furthermore, positive CK20 and CDX2 expression and negative CK7 expression were useful adjuncts in the immunohistochemical diagnosis of gastric metastases from colorectal adenocarcinoma.