CT appearance of disseminated peritoneal adenomucinosis.

Disseminated peritoneal adenomucinosis (DPAM) is a relatively rare cause of pseudomyxoma peritonei, marked by peritoneal lesions with abundant extracellular mucin and little cytologic atypia among exfoliated tumor cells, and usually associated with appendiceal adenomas. Peritoneal mucinous carcinomatosis (PMCA) also causes diffuse peritoneal tumor but is marked by neoplastic mucinous epithelium with cytologic features of carcinoma and associated with appendiceal, colon, gastric, or small bowel carcinoma. Compared with PMCA, DPAM has a different distribution of disease and a significantly better prognosis. DPAM is characterized by the lack of lymph node involvement, with primarily superficial peritoneal involvement, and a relatively benign, relapsing course over many years. Dominant primary masses may not be evident in DPAM. Despite considerable overlap in the two main causes of pseudomyxoma peritonei, there are features of the two that may help differentiate between them. We present the computed tomographic appearance of DPAM in a series of seven cases and emphasize characteristics of the disease.