Article
Common molecular cytogenetic pathway in papillary tumors of the pineal region (PTPR)
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Published: | April 28, 2011 |
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Objective: Primary papillary tumors of the central nervous system and particularly the pineal region are rare. Papillary tumor of the pineal region (PTPR) is a recently described neoplasm that has been formally recognized in the 2007 World Health Organization Classification of Tumors of the Nervous System.The differential diagnosis of PTPR is broad and includes all pineal region lesions known to exhibit papillary architecture. These include the pineal parenchymal tumors, papillary ependymoma, choroid plexus tumors, papillary meningioma and metastases. Even immunohistochemically, the differentiation of PTPR from other papillary tumors is challenging. Despite their histological alikeness, PTPR is considered to be clinically significantly different from ependymoma and choroid plexus papilloma, and the clinical course seems to be characterized be local recurrence. Treatment guidelines for PTPRs have not yet been established due to the low number of reported cases. However, an understanding of the biologic behavior of PTPR is important to evolve recommendations regarding the therapeutic management of PTPR. Today, only 4 PTPR been characterized cytogenetically.
Methods: We herein present three new cases of PTPR characterized by local recurrence. Primary and recurrent tumors were analyzed by comparative genomic hybridization.
Results: The chromosomal aberration in the PTPR of our three patients were clonal and included common loss of whole chromosome 10, as well as gain of chromosome 8, 9p and 12pq21. By adding the CGH results from our study to the 4 tumors presented in literature, 7 of 8 (88%) of PTPR show the loss of whole chromosome 10, and 7 of 8 (88%) show gains of 9p, 6 of 8 (75%) show gains of whole chromosome 4 and 12p12q21, 5 of 8 (63%) demonstrate gain of chromosome 8 (8q). From these results, a possible chromosomal tumor progression model can be postulated: primary chromosomal aberrations of PTPR are loss of chromosome 10 and gains of chromosome 4, 8 (8q) 9p and 12 (12p), which are followed by gains of chromosome 11, 20 (20p) and loss of 22q.
Conclusions: From our results a possible chromosomal tumor progression model can be postulated, which seems to be a feasible tool to differentiate PTPRs from other papillary tumors.