Sigmoid colonic metastasis by lymphatic spread occurring with unilateral Krukenberg tumor considered to be caused by stage IA early gastric cancer: A case report.

Gastric cancer is one of the most common malignancies in Asia, and the second most common cause of cancer-associated mortality in Japan. Colorectal metastases originating from gastric adenocarcinoma are extremely rare. The present study reports an unusual case of lymphogenous sigmoid metastasis of gastric adenocarcinoma occurring in a 58-year-old female patient. Endoscopic and radiological findings were indicative of 0-IIc+IIa early gastric cancer, and radical distal gastrectomy with D2 lymph node dissection was performed. The pathological diagnosis was stage IA gastric adenocarcinoma (T1bN0M0), according to the Japanese classification of gastric cancer. A follow-up examination at 18 months post surgery revealed a recurrence of paraaortic lymph node metastasis, detected by abdominal computed tomography (CT) and positron emission tomography (PET)/CT. The patient received chemotherapy with S-1 and cisplatin. Subsequently, radiotherapy was administered to the paraaortic lymph nodes at levels Th11-L3. Follow-up abdominal CT and PET/CT revealed an enlarged left ovary, and abnormal uptake in the left ovary and sigmoid colon. An oophorectomy and sigmoidectomy with D3 lymph node dissection were performed. The pathological diagnosis was metastatic adenocarcinoma; this was identical to the gastric pathology in the previous pathological report. The patient continued treatment with chemotherapy. Although sigmoid colonic metastasis from gastric cancer is extremely rare, metastasis from gastric cancer must be considered during the differential diagnosis of cases involving a colorectal mass and a previous history of gastric cancer.