[A Case of Rectal Cancer Presenting with Perianal Abscess].

An 81-year old man with a perirectal abscess was referred in May 2017 by another hospital. We observed swelling in the anal region at the 4 o'clock position and performed incisional drainage. Although this alleviated the pain and inflammation in the anal region, the irritation recurred in early June. The patient presented with bloody stools and a low-grade fever since late June. Pelvic magnetic resonance imaging(MRI)confirmed a solid tumor in the center of the lower rectum(Rb), outside of the anal fistula. We surmised this was rectal cancer. Colonoscopy revealed an ulcerative invasive(Grade 3)tumor extending more than halfway around the Rb; a biopsy confirmed a diagnosis of differentiated adenocarcinoma. Surgery was the preferred treatment option; however, as the patient also had the complication of anal fistula, there were concerns that the cancerous cells would contaminate the intraperitoneal area during surgery. We subsequently we decided to construct a colostomy and then start chemoradiotherapy. The patient began radiotherapy in the beginning of August, and received S-1 as a sensitizer. Contrast computed tomography(CT)and MRI at the completion of chemoradiotherapy confirmed that the rectal cancer had reduced in size. We scheduled later surgery, but the patient declined and preferred to continue with S-1. The tumor has continued to decrease in size, with good local control.

[A Case of SIADH in an Elderly Patient with Advanced Gastric Cancer].

An 82-year-old woman underwent surgery for gastric cancer at another hospital in May 2007. The pathological diagnosis was pT4a, pN2, M1, CY1, pStage Ⅳ. Although postoperative chemotherapy was administered, recurrence was observed on the abdominal wall in March 2014, and she was treated usingchemotherapy and resection. Intestinal obstruction due to peritoneal metastasis occurred in December 2017 and mid-July 2018 but symptoms improved with conservative treatment. In late August 2018, she was unable to eat and was readmitted to the hospital. Serum Na level at admission was low at 120 mEq/L, and Na correction was performed. Hyponatremia did not improve, and the serum Na level continued to decrease to 115mEq/L on the 14th day of hospitalization. Plasma osmolality was 229mOsm/kg, urine osmolality was 323mOsm/kg, and urine sodium concentration was 56mEq/L. Diagnosis of SIADH was made according to diagnosis standards. Hyponatremia improved by fluid restriction and Na correction. Subsequently, her peritoneal metastasis exacerbated, and she died in mid- October. We would like to report a case of SIADH in an elderly patient with advanced gastric cancer.