Malignant Peripheral Nerve Sheath Tumor in Cowden Syndrome. Issue 4 (April 2015)

• Record Type: Journal Article
• Authors: Taylor, Amy; Delon, Isabelle; Allinson, Kieren; Trotman, Jamie; Liu, Hongxiang; Abbs, Stephen; Tischkowitz, Marc
• Is Part Of: Journal of neuropathology and experimental neurology. Volume 74:Issue 4(2015:Apr.)
• Publication Date: 2015-04
• Subjects: Neurology -- Diseases -- Periodicals; Neurology -- Diseases -- Physiopathology -- Periodicals; 616.8047
• DOI: 10.1097/NEN.0000000000000178
• Languages: English
• ISSNs: 0022-3069

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <sec> <title>Abstract</title> <p>Malignant peripheral nerve sheath tumor is a rare malignancy, accounting for 3% to 10% of all soft-tissue sarcomas. We describe a previously healthy 48-year-old man who was diagnosed as having a high-grade malignant neoplasm involving the facial nerve in the right petrous canal after a 4-year history of deafness. The tumor was resected; histologic appearance and immunophenotype, including patchy but strong positivity for S100 protein, indicated a diagnosis of malignant peripheral nerve sheath tumor. A <italic>PTEN</italic> mutation, <italic>c.1003C</italic><italic>>T p.(Arg335Ter)</italic>, was subsequently identified as the cause of Cowden syndrome in another family member (a nephew) with dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease), and genetic testing in the proband's daughter indicated that he was an obligate carrier of the mutation. Sequencing of the tumor showed homozygosity for c.1003C>T, confirming the presence of a germline mutation and implying loss of the second allele. With the exception of Lhermitte-Duclos disease, tumors of the nervous system are not a prominent feature of Cowden syndrome, and this is the first report of malignant peripheral nerve sheath tumor in Cowden syndrome. Sequencing results in the tumor lend evidence to <italic>PTEN</italic> gene inactivation being implicated in tumorigenesis in this case, suggesting causality rather than chance association.</p> </sec> </abstract>