Toru Kameda1, Fukiko Kawai2, Nobuyuki Taniguchi3, Kiyoka Omoto4, Yasuyuki Kobori5, Kazukiyo Arakawa6. 1. Department of Ultrasound Medicine, Saiseikai Utsunomiya Hospital, 911-1 Takebayashi, Utsunomiya, Tochigi, 321-0974, Japan. kamekame@pb3.so-net.ne.jp. 2. Department of Ultrasound Medicine, Saiseikai Utsunomiya Hospital, 911-1 Takebayashi, Utsunomiya, Tochigi, 321-0974, Japan. 3. Department of Clinical Laboratory Medicine, Jichi Medical University, Shimotsuke, Japan. 4. Department of Laboratory Medicine, Saitama Medical Center, Jichi Medical University, Saitama, Japan. 5. Department of Clinical Laboratory, Saiseikai Utsunomiya Hospital, Utsunomiya, Japan. 6. Department of Radiology, Saiseikai Utsunomiya Hospital, Utsunomiya, Japan.
Abstract
PURPOSE: To evaluate whether the onion skin sign on ultrasonography (US) of the lower abdomen is specific for the diagnosis of an appendiceal mucocele. METHODS: Our study included 231 lesions from 229 patients in whom transabdominal US detected lesions in the lower abdomen and who had definitive pathological diagnoses in the small bowel, ileocecal valve, cecum, appendix, mesentery, adnexa uteri or pelvic cavity outside the major organs. Patients with metastatic tumors were excluded. We reviewed the reports and images from transabdominal US and checked for the presence of the onion skin sign. The sensitivity, specificity, and accuracy of the sign for the diagnosis of an appendiceal mucocele were calculated. RESULTS: Five (2.2 %) of the 231 lesions showed the onion skin sign on US and all were diagnosed with an appendiceal mucocele. The sensitivity, specificity, and accuracy of the sign for the diagnosis of an appendiceal mucocele were 63, 100, and 99 %, respectively. CONCLUSIONS: The onion skin sign in the lower abdomen appears to be specific for the diagnosis of an appendiceal mucocele. In cases where the onion skin sign is obviously present in the lower abdomen on US, an appendiceal mucocele should be considered as the leading diagnosis.
PURPOSE: To evaluate whether the onion skin sign on ultrasonography (US) of the lower abdomen is specific for the diagnosis of an appendiceal mucocele. METHODS: Our study included 231 lesions from 229 patients in whom transabdominal US detected lesions in the lower abdomen and who had definitive pathological diagnoses in the small bowel, ileocecal valve, cecum, appendix, mesentery, adnexa uteri or pelvic cavity outside the major organs. Patients with metastatic tumors were excluded. We reviewed the reports and images from transabdominal US and checked for the presence of the onion skin sign. The sensitivity, specificity, and accuracy of the sign for the diagnosis of an appendiceal mucocele were calculated. RESULTS: Five (2.2 %) of the 231 lesions showed the onion skin sign on US and all were diagnosed with an appendiceal mucocele. The sensitivity, specificity, and accuracy of the sign for the diagnosis of an appendiceal mucocele were 63, 100, and 99 %, respectively. CONCLUSIONS: The onion skin sign in the lower abdomen appears to be specific for the diagnosis of an appendiceal mucocele. In cases where the onion skin sign is obviously present in the lower abdomen on US, an appendiceal mucocele should be considered as the leading diagnosis.
Authors: Genevieve L Bennett; Teerath P Tanpitukpongse; Michael Macari; Kyunghee C Cho; James S Babb Journal: AJR Am J Roentgenol Date: 2009-03 Impact factor: 3.959