2020 Volume 53 Issue 10 Pages 808-816
A 87-year-old man visited a nearby clinic with the chief complaint of frequent urination. CT showed an ileocecal mass. Lower gastrointestinal endoscopy showed no abnormalities on the mucosal surface. Since he was old and had no subjective symptoms, he did not wish to undergo surgery. The abdominal mass had a maximum diameter of 6.1 cm at the time of detection, and increased 8.6 cm after 10 months, and 17 cm after 17 months. A feeling of fullness in his abdomen also developed and he requested to undergo surgery. He was ultimately referred to our hospital 18 months after the abdominal mass had been discovered. He underwent open right hemicoloectomy including D3 lymph node dissection. Histopathological examination revealed a 25×18×13 cm large ascending colon leiomyosarcoma with extramural growth. Since 1998, when the gastrointestinal stromal tumor (GIST) concept was established, leiomyosarcoma of colon has been extremely rare. There have been 18 cases reported in Japan, including our case. Extramural growth occurs less frequently than intramural growth. Our case was rare as it represented the largest tumor size and had an 18-month observation period prior to surgery.
