Choroid plexus papilloma

Choroid plexus papilloma Large mass with structure of choroid plexus Laminin (-I-) cytokeratin (-I-) transthyretin (S) synaptophysin ICF-II Fourth ventricle lateral ventricle CP angle choroid plexus... 

Rare ependymomas have sparse CK or EMA immu-noreactivity on their most differentiated epithelium. However, even these have much less CAM5.2 than choroid plexus papillomas and carcinomas. CAM5.2 is recommended to distinguish them. 

In contrast to papillary ependymoma, the choroid plexus papilloma contains a layer of columnar to cuboidal epithelial cells over a basement membrane and fibrovas-cular stroma. The type IV collagen and laminin in this stroma contrast with ependymomas, which have solid parenchyma without collagen or laminin (see Tables... 

Newer potential markers of choroid plexus papillomas include insulin-like growth factor II (IGF-II) and synaptophysin. IGF-II is found in papillomas but not in normal choroid plexus.Synaptophysin is present in some normal choroid plexus, choroid plexus papilloma, and choroid plexus carcinoma but not in metastatic papillary carcinoma.Both markers may assist in the differential diagnoses of some tumors, but I find them most useful combined with traditional markers. CD44 is preferentially expressed on atypical papilloma and choroid plexus carcinoma and may be a marker of aggressive choroid plexus tumors. Aggressive tumors have higher mean MIBl Lis of These various... 

Meningiomas and carcinoma enter the differential diagnosis. An epithelial lining of CAM5.2 cytokeratin-positive cells in the choroid plexus papilloma, lack of... 

FIGURE 20.36 Choroid plexus papilloma. This choroid plexus papilloma from the lateral ventricle of a child is composed of well-differentiated columnar epithelium resting upon a fibrovascular stroma. It expresses CAMS.2 low molecular weight cytokeratin (A) and transthyretin (B). The fibrovascular stroma is easily identified from its negativity for cytokeratin. (Immunoperoxidase anti-CAM5.2 and anti-prealbumin.)... 

The choroid plexus carcinoma (anaplastic choroid plexus papilloma) is a rare neoplasm that is most difficult to distinguish from metastatic carcinoma (see Table... 

The recognition of a papillary meningioma in other than the dural locations characteristic of meningioma is difficult. Papillary meningiomas resemble papillary ependymomas, choroid plexus papillomas, and carcinomas.One should look for a high ratio of vimentin to CK and absence of GFAP to identify the meningioma. 

Kubo S, Ogino S, Fukushima T, et al. Immunocytochemical detection of insulin-like growth factor II (IGF-II) in choroid plexus papilloma A possible marker for differential diagnosis. Clin Neuropathol. 1999 18 74-79. 

Each of these tumors produces CK, and each may produce transthyretin. A transitional zone between papilloma and carcinoma of the choroid plexus confirms choroid plexus carcinoma. Primary carcinoma of the choroid plexus so closely resembles metastatic carcinoma that the latter must be carefully excluded before the diagnosis of primary choroid plexus carcinoma can be made. Occult pulmonary or gastrointestinal primary tumors are common sources. The paucity of these primary systemic carcinomas in children facilitates diagnosis of choroid plexus carcinoma in a patient in this age group. Some choroid plexus carcinomas express CD44 cell adhesion molecule not seen in the most benign papillomas. The mean MIBl LI of choroid plexus carcinomas... 

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