Choroid plexus carcinoma

Weitman et al. showed by Northern blot analysis and immunoassays that the folate receptor (type-a) has a very restricted normal tissue distribution (4). Highly elevated receptor expression was only found in the choroid plexus and malignant tissues (4). Garin-Chesa et al. showed by immunohistochemi-cal staining that 52 of 56 ovarian tumor samples displayed highly elevated folate receptor (type-a) expression (5). Receptor overexpression was also found in 10 of 11 endometrial, 6 of 27 colorectal, 11 of 53 breast, 6 of 18 lung, 9 of 18 renal cell, 4 of 5 brain metastases, and 3 of 21 neuroendocrine carcinomas (5). 

Gyure KA, Morrison AL. Gytokeratin 7 and 20 expression in choroid plexus tumors utility in differentiating these neoplasms from metastatic carcinomas. Mod Pathol. 2000 13(6) 638-643. 

The polyphenotypic immunohistochemical prohle of MRT presents challenges in the differential diagnosis, particularly with DSRCT, RMS, choroid plexus carcinoma, and epithelioid sarcoma. In particular, the absence of INIl protein in proximal-type epithelioid sarcoma, in a subset of central nervous system primitive neuroectodermal tumors without a rhabdoid phenotype and in renal medullary carcinoma, suggests the existence of a wider family of hSNP5/INIl-deficient The lack of expression of INIl protein... 

Choroid plexus carcinoma Above features with anaplasia and mitoses (necrosis) Cytokeratin (-I-) CD44 synaptophysin transthyretin (R) Preceding locations... 

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. 

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... 

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

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... 

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. 

Important characteristics of carcinoma as it relates to the CNS and meninges are its distinctively epithelial structure (Fig. 20.58A see Table 20.6) and the overwhelming predominance of metastatic over primary carcinomas. Metastatic carcinomas are described in detail in Chapter 8, Immunohistology of Metastatic Carcinomas of Unknown Primary. Rare primary brain carcinomas occur in the choroid plexus, from germ cell tumors of the pineal and suprasellar regions, and from cysts. 725 section emphasizes how to distinguish between carcinomas (see Fig. 20.58B to D) and various primary intracranial tumors (see Box 20.2). 

Kepes JJ, Collins J. Choroid plexus epithelium (normal and neoplastic) expresses synaptophysin A potentially useful aid in differentiating carcinoma of the choroid plexus from metastatic papillary carcinomas. J Neuropathol Exp Neurol. 1999 58 398-401. 

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