Primary mucinous cystadenocarcinoma of the appendix with pseudomyxoma peritonei manifested as a splenic mass.

We have reported a case of pseudomyxoma peritonei manifested as a splenic mass in a 38-year-old woman. Upon reviewing previously reported cases of pseudomyxoma peritonei with visceral involvement or extension above the diaphragm, we conclude that such spread of the disease does not significantly alter the prognosis. Furthermore, our findings support the concept that pseudomyxoma peritonei represents the implantation of malignant cells rather than metaplastic transformation of mesothelial cells.