[A Case Report of Gastric Cancer with Positive Peritoneal Lavage Cytology and Metachronous Schnitzler's Metastasis Treated with Multimodality Therapy].

A69 -year-old male patient with type 3 gastric cancer in pyloric antrum underwent distal gastrectomy with regional lymphadenectomy. Serosal infiltration of cancer tissue was found in the anterior wall of antrum, and the evaluation of peritoneal lavage cytology were positive. Pathological analysis showed the tumor was mainly consist of moderately tubular adenocarcinoma and strongly positive for HER2 stain. Postoperatively, combined therapy of capecitabine and trastuzumab was carried out, but cisplatin was excluded because of the patient's rejection. However, nine months after drug withdrawal, singular tumor located at left anterior side of rectum was detected by abdominal CT scan. Colonoscopy revealed its mucosal invasion and the result of biopsy was metastasis of gastric cancer, also known as Schnitzler's metastasis. Local radiation therapy aimed at the tumor was performed, followed by capecitabine and oxaliplatin therapy for 18 months. After the therapy, Schnitzler's metastatic lesion was disappeared and biopsy from colonic mucosa revealed there was no tumor tissue left. The patient has been in good health 5 years after surgery. This case suggests that multimodality therapy including radiation and chemotherapy might improve survival of gastric cancer patient with positive peritoneal lavage cytology and metachronous metastasis.