Letter to Editor about "A Case of Appendiceal Mucocele due to Low-grade Appendiceal Mucinous Neoplasm Correctly Differentiated from Acute Appendicitis Based on Diffusion-weighted Imaging and the Apparent Diffusion Coefficient Value (JJMRM 2020; 40: 14-19)".

概要

We appreciate the opportunity to introduce a case report by Inoue A et al.1 to be published in the Japanese Journal of Magnetic Resonance in Medicine (JJMRM). An appendiceal mucocele, which is defined as a mucus-containing appendix, can be caused by low-grade appendiceal mucinous neoplasm (LAMN). Surgical resection is required during the early stages of the disease to avoid dissemination. A symptomatic appendiceal mucocele related to inflammation or perforation causes right lower abdominal pain that resembles acute appendicitis. These conditions require different therapeutic strategies, so it is essential to distinguish one from the other. However, it can sometimes be challenging to differentiate the two conditions using CT alone.

　The authors concluded that DWI showing (i) a dilated appendix with a high-intensity wall, and (ii) the appendi- ceal contents has a relatively large apparent diffusion coefficient, might be characteristic of appendiceal mucocele due to LAMN, which would be helpful in distinguishing the condition from acute appendicitis. Therefore, if a case of suspected appendiceal mucocele remains equivocal following CT, the patient should selec- tively undergo additional MRI examination, in particular DWI, to confirm the diagnosis and determine the correct therapeutic strategy.