Winona W Wu1, Wenya Linda Bi1, Yun Jee Kang2, Shakti H Ramkissoon2, Sashank Prasad3, Helen A Shih4, David A Reardon5, Ian F Dunn6. 1. Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. 2. Department of Pathology, Division of Neuropathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. 3. Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. 4. Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA. 5. Center for Neuro-Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA. 6. Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. Electronic address: idunn@partners.org.
Abstract
BACKGROUND: Atypical teratoid/rhabdoid tumors (AT/RTs) are highly malignant neoplasms that rarely occur in adults. Due to the complex histology of AT/RTs, the differential diagnosis of these tumors is quite challenging and increasingly relies on demonstration of characteristic SMARCB1/INI1 inactivation in tumor cells. CASE DESCRIPTION: A 51-year-old man presented with diplopia, lethargy, and memory deficit owing to Parinaud syndrome and hydrocephalus. Magnetic resonance imaging revealed a T2-hyperintense and homogeneously enhancing tectal mass that extended to the pineal region. Initial biopsy suggested a World Health Organization grade II myxopapillary astrocytoma. However, subsequent definitive resection revealed an AT/RT, with loss of SMARCB1/INI1 observed through immunohistochemical staining as well as array cytogenetic analysis. Molecular profiling revealed additional mutations in RHPN2(L385I), MDM4(D396G), FLT3(V194M), and NPRL3(D53N). CONCLUSIONS: Pathologic diagnoses in the modern era increasingly integrate molecular data for confirmation as well as prognostication. We present a rare case of a tectal AT/RT in an adult patient and report several novel mutations previously unrecognized in this tumor subtype, in addition to canonical SMARCB1/INI1 loss. Further investigation of these novel variants may improve understanding of the pathogenesis underlying AT/RTs.
BACKGROUND: Atypical teratoid/rhabdoid tumors (AT/RTs) are highly malignant neoplasms that rarely occur in adults. Due to the complex histology of AT/RTs, the differential diagnosis of these tumors is quite challenging and increasingly relies on demonstration of characteristic SMARCB1/INI1 inactivation in tumor cells. CASE DESCRIPTION: A 51-year-old man presented with diplopia, lethargy, and memory deficit owing to Parinaud syndrome and hydrocephalus. Magnetic resonance imaging revealed a T2-hyperintense and homogeneously enhancing tectal mass that extended to the pineal region. Initial biopsy suggested a World Health Organization grade II myxopapillary astrocytoma. However, subsequent definitive resection revealed an AT/RT, with loss of SMARCB1/INI1 observed through immunohistochemical staining as well as array cytogenetic analysis. Molecular profiling revealed additional mutations in RHPN2(L385I), MDM4(D396G), FLT3(V194M), and NPRL3(D53N). CONCLUSIONS: Pathologic diagnoses in the modern era increasingly integrate molecular data for confirmation as well as prognostication. We present a rare case of a tectal AT/RT in an adult patient and report several novel mutations previously unrecognized in this tumor subtype, in addition to canonical SMARCB1/INI1 loss. Further investigation of these novel variants may improve understanding of the pathogenesis underlying AT/RTs.
Authors: Amandine Crombé; Nicolas Alberti; Nicolas Villard; Frank Pilleul; Xavier Buy; François Le Loarer; Michèle Kind Journal: Eur Radiol Date: 2019-02-14 Impact factor: 5.315
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