Pancreatic mucinous cystadenocarcinoma with pseudosarcomatous mural nodules. A report of a case with immunohistochemical study. A case of pancreatic mucinous cystadenocarcinoma (PMC) with two pseudosarcomatous mural nodules (PMN) is described. These nodules have not been previously described in this type of tumor. In ovarian mucinous tumors (OMT), similar nodules have been reported, the nature of which has been discussed in detail. Here the similarity between the tumor described here and ovarian tumors is stressed. The immunohistochemical study carried out disclosed in the nodules strong positive staining for vimentin and moderate positivity for keratin and epithelial membrane antigen. These findings, along with histologic details, favor the epithelial nature of the nodules. It was concluded that the nodules are foci of anaplastic carcinoma with high proliferative cell rate, which could explain the coexpression of vimentin and keratin. 