This a case of mucinous cystadenoma of the appendix in a 70 y/o man who presented with pain in the right iliac fossa. Ultrasonography demonstrated an enlarged appendix measuring 8 cm in length and 5 cm in maximum diameter. The appendectomy specimen (shown here and in the next image) had cystic areas filled with mucinous material. Histologically, the cysts were lined by mucinous columnar epithelium. Case courtesy of: Dr. Sanjay D. Deshmukh, Department of Pathology, Smt. Kashibai Navale Medical College, Pune, India.