Pseudomyxoma Peritonei

A 67-year-old man presented with right lower quadrant pain of 3 days' duration. CT findings suggested acute appendicitis with ascites and omental caking. Laparotomy revealed a ruptured appendix, which was removed, and numerous gelatinous deposits throughout the abdomen. Extensive debulking was not performed because of the risk of intraoperative and postoperative bleeding.

Histopathological examination of the resected appendix revealed well-differentiated mucinous cystadenocarcinoma. Pseudomyxoma peritonei was diagnosed based on the presence of metastatic mucin-producing tumor cells in the peritoneum.

A fluctuant violaceous nodule arose in the patient's umbilicus 1 year after the initial diagnosis. The nodule seemed cystic but was nontender. A CT scan of the abdomen showed multiple new tumor deposits.

The differential diagnosis of a lump in the umbilicus consists of benign entities, such as umbilical hernias, and disseminated disease (eg, intra-abdominal malignancy, Sister Mary Joseph nodule, peritoneal carcinomatosis). Pseudomyxoma peritonei belongs to a family of tumors that includes adenocarcinoid goblet cell tumors, goblet cell carcinomas, mucinous cystadenocarcinomas, and signet-ring cell carcinomas; however, it also may result from rupture of a benign mucocele of the appendix or a cystadenoma of the ovary.^1,2

Pseudomyxoma peritonei is typically resistant to standard chemotherapy and radiation therapy. It is best treated with extensive surgery and possibly intraperitoneal chemotherapy. As the disease progesses, gelatinous masses typically develop throughout the abdomen and can lead to bowel obstruction. This patient declined further treatment. At 2-year follow-up, he was minimally symptomatic.

References:

REFERENCES:1.Ronnett BM, Zahn CM, Kurman RJ, et al. Disseminated peritoneal adenomucinosis and peritoneal mucinous carcinomatosis. A clinicopathologic analysis of 109 cases with emphasis on distinguishing pathologic features, site of origin, prognosis, and relationship to "pseudomyxoma peritonei." J Surg Pathol. 1995;19:1390-1408.
2. Ronnett BM, Yan H, Kurman RJ, et al. Patients with pseudomyxoma peritonei associated with disseminated peritoneal adenomucinosis have a significantly more favorable prognosis than patients with peritoneal mucinous carcinomatosis. Cancer. 2001;92:85-91.