This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Caspi, B. Articles by Appelman, Z. Search for Related Content PubMed PubMed Citation Articles by Caspi, B. Articles by Appelman, Z.

The Onion Skin Sign

A Specific Sonographic Marker of Appendiceal Mucocele

Ultrasound Unit, Department of Obstetrics and Gynecology, Kaplan Medical Center, Rehovot, Israel (affiliated with the Medical School of the Hebrew University and Hadassa, Jerusalem, Israel) (B.C., E.C., Z.H., Z.A.); Department of Obstetrics and Gynecology, Carmel Medical Center, Haifa, Israel (R.A.); and Department of Obstetrics and Gynecology, Assaf Harofe Medical Centre, Beer Yaakov, Israel.

Address correspondence and reprint requests to Benjamin Caspi, MD, Ultrasound Unit, Department of Obstetrics and Gynecology, Kaplan Medical Center, Rehovot 76100, Israel. E-mail: bcaspi{at}inter.net.il.

Objective. To evaluate the association of the onion skin sign as a sonographic marker for appendiceal mucocele. Methods. The sonographic onion skin sign was considered specific for the preoperative diagnosis of appendiceal mucocele. Therefore, detection of this sign in a mass located in the right lower abdomen, unrelated to the female reproductive organs, indicated surgical intervention with a presumptive diagnosis of appendiceal mucocele. From 1998 through 2001, female patients who were found to have atypical cysts containing this sign underwent surgery. The cases were closely followed, and intraoperative findings and final histologic diagnoses were recorded. Results. Appendiceal mucocele was the final diagnosis in all 7 patients in whom the onion skin sign was observed. One additional patient had an appendiceal mucocele with a sonographic picture of a clear tubular cystic structure. Conclusions. A sonographically layered cystic mass in the right lower quadrant of the abdomen in the presence of a normal ovary strongly suggests the diagnosis of appendiceal mucocele. Recognition of the sonographic onion skin sign in a cystic mass in the right lower quadrant may facilitate the accurate preoperative diagnosis of appendiceal mucocele.

Key Words: appendix • echogenic layers • mucocele • onion skin • sonography

Abbreviations: AM, appendiceal mucocele • MCA, mucinous cyst adenoma

This article has been cited by other articles:

				I. Honnef, M. Moschopulos, and T. Roeren Best Cases from the AFIP: Appendiceal Mucinous Cystadenoma RadioGraphics, September 1, 2008; 28(5): 1524 - 1527. [Full Text] [PDF]

				T. Hamada, K. Kosaka, N. Shigeoka, Y. Hashimoto, M. Yamauchi, S. Cho, K. Nakai, S. Ishimaru, and K. Suenaga Torsion of the Appendix Secondary to Appendiceal Mucocele: Gray Scale and Contrast-Enhanced Sonographic Findings J. Ultrasound Med., January 1, 2007; 26(1): 111 - 115. [Full Text] [PDF]

				G. Francica, G. Lapiccirella, C. Giardiello, F. Scarano, G. Angelone, F. De Marino, and V. Molese Giant mucocele of the appendix: clinical and imaging findings in 3 cases. J. Ultrasound Med., May 1, 2006; 25(5): 643 - 648. [Abstract] [Full Text] [PDF]