Answer for BIR CoW 12 Apr 2026
Neoplastic Appendiceal Mucocele
Findings
An oblong T2w hyperintense cystic lesion measuring about 10.3 x 4.8 cm in the right iliac fossa extending to the right side of pelvis. Laterally it is seen extending up to the caecum. Medially the lesion extends and abuts the right ovary. Few foci of blooming is seen along the wall - representing calcification. Few thin internal septation seen within. Few small T2w iso to hypoechoic mural nodular foci seen attached to the wall. No significant restricted diffusion on DWI images.
Discussion
Appendiceal mucocele is a cystic dilatation of the appendix due to mucin accumulation, ranging from benign retention cyst to neoplastic lesions such as mucinous cystadenoma or LAMN. Imaging typically shows a tubular or oblong T2 hyperintense cystic lesion in the right iliac fossa, contiguous with the caecum and separate from the ovary, which is the key differentiating feature from adnexal masses. Wall calcification is characteristic, while mural nodularity suggests neoplastic etiology. Diffusion restriction is usually absent unless high-grade malignancy is present. The major complication is pseudomyxoma peritonei due to rupture. In this case, the large size, calcified wall and mural nodules favor a neoplastic appendiceal mucocele.
Findings
An oblong T2w hyperintense cystic lesion measuring about 10.3 x 4.8 cm in the right iliac fossa extending to the right side of pelvis. Laterally it is seen extending up to the caecum. Medially the lesion extends and abuts the right ovary. Few foci of blooming is seen along the wall - representing calcification. Few thin internal septation seen within. Few small T2w iso to hypoechoic mural nodular foci seen attached to the wall. No significant restricted diffusion on DWI images.
Discussion
Appendiceal mucocele is a cystic dilatation of the appendix due to mucin accumulation, ranging from benign retention cyst to neoplastic lesions such as mucinous cystadenoma or LAMN. Imaging typically shows a tubular or oblong T2 hyperintense cystic lesion in the right iliac fossa, contiguous with the caecum and separate from the ovary, which is the key differentiating feature from adnexal masses. Wall calcification is characteristic, while mural nodularity suggests neoplastic etiology. Diffusion restriction is usually absent unless high-grade malignancy is present. The major complication is pseudomyxoma peritonei due to rupture. In this case, the large size, calcified wall and mural nodules favor a neoplastic appendiceal mucocele.
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
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Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!