Mucin deposits within inguinal hernia sacs: a presenting finding of low-grade mucinous cystic tumors of the appendix. A report of two cases and a review of the literature.

Two male patients, both 41 years of age, presented clinically with a typical inguinal hernia. The herniorrhaphy specimens were found on routine pathologic examination to contain abundant mucin that was focally organizing and was devoid of associated epithelial cells. Both cases were seen in consultation because of uncertainty as to the nature of the process. The possibility that the mucin might represent spread from an appendiceal mucinous cystic tumor led to the investigation of the appendix and in both cases such a tumor was discovered. The widespread involvement of the peritoneum that is characteristic of pseudomyxoma peritonei was absent in each case. These cases represent one of the many "surprise" findings that may be encountered in hernia sac specimens and one of the many problematic pathologic manifestations that may be associated with low-grade mucinous neoplasms of the appendix. Although this phenomenon is described in the literature, experience with our two cases indicates that it may still pose a significant diagnostic challenge.