A gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract and expresses CD117, a c-kit proto-oncogene, which can be detected immunohistochemically. We reported a GIST of the rectum of a 61-year-old-woman who had visited emergency room complaining of constipation over one week. Upon rectal examination, a round hard mass was palpated. Colonoscopy showed a 7×5 cm sized protruded lesion with surface ulceration on a rectum, adjacent the anus. And abdomen computed tomography revealed the soft tissue mass compressing anterolateral wall of the rectum and these findings suggest possibility of rectal submucosal tumor such as GIST. The patient had been treated with a ultra anorectal anastomosis with loop ileostomy. Immunohistochemical studies on the surgically resected specimen showed c-kit (+) and CD34 (+). The final diagnosis was a GIST of the rectum. She was grouped into high risk and she has been given adjuvant chemotherapy with Imatinib.

Blockers of renin-angiotensin system(RAS) including ACE inhibitor or ARB are one of the most frequently prescribed medications for the treatment of hypertension, heart failure and proteinuria. One of the major side effects of these RAS blockers is the deterioration of renal function, mainly due to a reduction of intraglomerular pressure. Therefore, close monitoring of renal function is recommended when RAS blockers are initially prescribed, especially for the patients with impaired renal function.

We report a patient who was transferred to our hospital due to the sudden development of oliguria and dyspnea after treatment for hypertension with ACEi and ARB. She was finally diagnosed as RAS blocker-induced acute renal failure with pulmonary edema complicated on congenital solitary kidney. After hemodialysis and conservative treatment, her renal function was recovered with maintenance of normal urine output.