Choroid plexus carcinoma: a new case associated with a novel TP53 germ line mutation

How to Screen for Hereditary Cancers in General Pathology Practice

CONTEXT

-As a pathologist, an awareness of the particular diagnoses that can serve as "sentinels" for an underlying genetic syndrome can be incredibly beneficial to patients and their families. This is a complex and ever-changing field of medicine, where remaining up to date with diagnostic and treatment options is challenging. Simply raising the possibility of an underlying syndrome may not, in itself, be diagnostic; however, this may present an opportunity for genetic assessment, and possibly early intervention or primary prevention of disease in the kindred. In the last decade, immunohistochemistry has emerged as a useful tool in hereditary cancer screening. This is best exemplified by the use of mismatch repair immunohistochemistry as a screening tool in colorectal and endometrioid carcinomas. Reflex testing of all tumors for deficiencies in these proteins is now resulting in superior identification and treatment of Lynch-associated cancers, and families harboring these syndromes. Despite the success and potential value of immunohistochemistry as a genetic screening tool, hematoxylin-eosin morphology remains a valuable tool for hereditary cancer screening and is the focus of this article.

OBJECTIVE

-To highlight the utility of hematoxylin-eosin morphology as a valuable tool for hereditary cancer screening.

DATA SOURCES

-Primary literature review with PubMed.

CONCLUSIONS

-Recognition of tumors associated with cancer predisposition may identify individuals and families at high risk for cancer and may also have peridiagnostic utility with regard to implications for targeted therapy.

A novel TP53 somatic mutation involved in the pathogenesis of pediatric choroid plexus carcinoma

Background

Choroid plexus carcinoma (CPC) is an uncommon, aggressive, malignant, central nervous system neoplasm that typically occurs in children, presenting with the signs and symptoms of intracranial hypertension and cerebrospinal fluid obstruction.

Case Report

We report the case of a 2.5-year-old girl with CPC. The tumor was subtotally removed by microsurgery, followed by gamma knife radiosurgery for the residual lesion. H&E staining indicated that this was a rare case of CPC. Neuropathological studies, assayed by immunohistochemical staining, showed that the tumor sample was positive to antibodies against S-100, CgA, AE1/AE3 (cytokeratin), Ki-67, INI1 and TP53, and was negative to antibodies against Nestin, GFAP, CD133, EMA and AFP. Moreover, stainings for transthyretin and vimentin were focally positive. Interestingly, direct DNA sequencing of the paraffin-embedded tumor sample identified a novel R248Q mutation in the TP53 gene. In contrast to previous reports suggesting that TP53 germline mutations were associated with the pathogenesis of CPC, here we provide a rare case of CPC with TP53 somatic mutation, as evidence that the peritumoral tissue possesses the non-mutant TP53 allele.

Conclusions

Our finding suggests that TP53 somatic mutations, in addition to its germline mutations, may also be involved in the pathogenesis of pediatric CPC.

Choroid plexus tumors; management, outcome, and association with the Li-Fraumeni syndrome: the Children's Hospital Los Angeles (CHLA) experience, 1991-2010

BACKGROUND

Choroid plexus tumors (CPT) are rare, and predominate in early childhood. An association with the Li-Fraumeni syndrome (LFS) has been reported, but the biological and clinical implications of this association remain poorly defined. We have investigated the clinical features and overall survival of all CPT patients treated at Children's Hospital Los Angeles (CHLA) over a 20-year period, with particular attention to the association of CPT with LFS.

METHODS

A retrospective evaluation of the course of therapy and clinical outcome was undertaken on the 42 patients diagnosed with and treated for CPT at CHLA from January 1991 to December 2010. Any association with multiple primary tumors and family histories consistent with LFS was investigated in all patients.

RESULTS

Six of the 42 patients (16.7%), demonstrated either phenotypic and/or genotypic characteristics consistent with LFS, with either a distinct family history of cancer, a synchronous diagnosis of a different type of cancer, or the subsequent development of metachronous cancers. Of 11 patients with choroid plexus carcinoma tested for TP53 germline mutations, four (36.4%) were positive. A single patient with a choroid plexus papilloma had phenotypic characteristics of LFS but tested negative for TP53.

CONCLUSIONS

Children with CPC appear to have a high frequency of TP53 germline mutations in association with LFS. This raises the question whether all children with CPC should be tested for TP53 germline mutations in order to institute screening to enhance early detection and treatment of subsequent cancers.