Pseudomyxoma peritonei (PMP) is an unusual form of intraabdominal
neoplasm that produces a large amount of extracellular
mucin. It is often associated with mucinous
tumors of gastrointestinal tract or ovary. Herein, we report 3 patients with
pseudomyxoma peritonei with high serum
carbohydrate antigen 19-9 (CA19-9) levels. The first patient, who had a CA19-9 level of 1132 U/ml, had well-differentiated
rectal cancer and died of
chemotherapy complications,
pneumonia and
septic shock; one month after admission. The other 2 cases with CA19-9 levels of 2520 U/ml and 679 U/ml had
tumors of unknown origins and had survived more than 1 year and 3 months
after treatment, respectively. Usually, elevated serum CA19-9 levels are found in patients with pancreatic, biliary, colorectal, gastric or
liver cancers. However, many studies have shown high serum CA19-9 levels are associated with
mucinous carcinoma. Immunochemical studies also showed positive staining of CA19-9 in mucinous
tumors. PMP is composed of large amounts of
mucin, therefore, we suggest that serum and
ascites CA19-9 levels should be routinely checked in patients with PMP.