Rectal leiomyosarcoma diagnosed by endoscopic ultrasonography

A 67 year-old man was admitted to the Tainan Municipal Hospital due to a pr otruding mass, usually noted during defecation. Digital examination reveale d a single, smooth, large mass over the rectum, occupying almost the entire lumen. Colonoscopy, barium enema, and computed tomography (CT) demonstrate d a submucosal tumor of the rectum. Endoscopic ultrasound (EUS) study showe d that the tumor originated from the muscle layer. Based on the size, margi n and echogenicity of the mass, a malignant neoplasm, probably leiomyosarco ma, was diagnosed. Post-operative histologic examination confirmed that the resected tumor was leiomyosarcoma. Existing ancillary procedures like colonoscopy, abdominal CT, magnetic reso nance image (MRI), and barium enema are neither reliable nor accurate in lo cating which layer the lesion originates. Colonoscopic biopsy is disappoint ing since submucosal tumor is usually inaccessible. EUS study can provide u s with a more distinct image with regards to tumor origin, size, margin and echogenicity. This report emphasizes the important role of EUS in the pre- operative diagnosis of submucosal tumors of the rectum. Furthermore, this t ool can aid the surgeons whether wide excision or an abdomino-perineal rese ction should be performed.