Disseminated Adult Atypical Teratoid Rhabdoid Tumor causing Dorsal Midbrain Syndrome

A 36-year-old woman with no significant past medical history presented with 1 month of severe headaches and vomiting associated with abnormal eye movements. MRI demonstrated an enhancing mass along the splenium of the corpus callosum and in the pineal region extending towards the right thalamus with a necrotic center. Her vision was 20/25 OU, and pupils were round and slowly reactive to light without relative afferent pupillary defect. Extraocular movements revealed -4 upgaze deficits bilaterally, partially overcome by oculocephalic maneuvering. Convergence retraction nystagmus and light-near dissociation were present. Dilated fundus exam was unremarkable OU.

Poster 99 Disseminated Adult Atypical Teratoid Rhabdoid Tumor causing Dorsal Midbrain Syndrome Colleen Yard1, Hannah Muniz-Castro2, Yoshua Esquenazi3, Leomar Ballester4, Bhattacharjee, Meenakshi Bhattacharjee4, Susana Calle5, Ore-Ofeoluwatomi Adesina2 The University of Texas Health Science Center at Houston-McGovern Medical School, Houston, Texas, USA, 2UT Health Science Center Houston-McGovern Medical School Department of Ophthalmology, Houston, Texas, USA, 3UT Health Science Center Houston-McGovern Medical School Department of Neurosurgery, Houston, Texas, USA, 4UT Health Science Center Houston- McGovern Medical School Department of Pathology, Houston, Texas, USA, 5UT Health Science Center Houston- McGovern Medical School Department of Radiology, Houston, Texas, USA 1 Introduction: A 36-year-old woman with no significant past medical history presented with 1 month of severe headaches and vomiting associated with abnormal eye movements. MRI demonstrated an enhancing mass along the splenium of the corpus callosum and in the pineal region extending towards the right thalamus with a necrotic center. Her vision was 20/25 OU, and pupils were round and slowly reactive to light without relative afferent pupillary defect. Extraocular movements revealed -4 upgaze deficits bilaterally, partially overcome by oculocephalic maneuvering. Convergence retraction nystagmus and light-near dissociation were present. Dilated fundus exam was unremarkable OU. Description of Case(s): She initially underwent stereotactic biopsy. The results, limited by a small tissue specimen, were consistent with a glioneuronal tumor. Final pathology from a larger specimen showed a high-grade tumor with chordoid architecture and rhabdoid cytologic features. The tumor was positive for epidermal growth factor receptor (EGFR) and SMARCB1 mutations. Mutation and inactivation of SMARCB1 have been identified as the underlying mechanism in the development of Malignant Rhabdoid and Atypical Teratoid/Rhabdoid Tumors. Postoperative imaging demonstrated residual tumor that was not amenable to resection, and adjuvant external beam radiation was performed. Conclusions, including unique features of the case(s): Based on clinical and radiographic evidence, the patient initially appeared to have an aggressive pineal region meningeal tumor with metastasis. However, initial pathology showed a benign glioneuronal tumor. She deteriorated rapidly from progressive tumor growth and venous obstruction causing hydrocephalus. Final pathology ultimately revealed an adult Atypical Teratoid Rhabdoid Tumor (ATRT) with leptomeningeal spread along the biopsy and shunt tracts. A combined approach of whole spine radiation and intrathecal chemotherapy was planned. Molecular testing revealed an activation of the EGFR pathway that would be sensitive to the tyrosine kinase inhibitor osimertinib. She underwent whole spine radiation and intrathecal chemotherapy; however, she ultimately developed widespread CNS metastasis with involvement of the spinal cord and multiple cranial nerves bilaterally. References: Kim EY, Weon, Kim ST, Kim HJ, Byun et al. Rhabdoid meningioma: clinical features and MR imaging findings in 15 patients. AJNR Am J Neuroradiol. 28(8), 1462-5, 2007. Rogerio, De araújo zanardi, Ribeiro de menezes netto, De souza queiroz. Meningioma with rhabdoid, papillary and clear cell features: case report and review of association of rare meningioma variants. Clin Neuropathol, 30(6), 291-6, 2011. Wu, Ho, Lin YJ, Lin JW. Rhabdoid papillary meningioma: a clinicopathologic case series study. Neuropathology, 31(6): 599-605, 2011. Sangoi, Dulai, Beck, Brat, Vogel. Distinguishing chordoid meningiomas from their histologic mimics: an immunohistochemical evaluation. Am J Surg Pathol, 33(5), 669-81, 2009. Darr, Klochendler, Isaac, Geiger, Eden. Phosphoproteomic analysis reveals Smarcb1 dependent EGFR signaling in Malignant Rhabdoid tumor cells. Mol Cancer, 14, 167, 2015. Keywords: Ocular Motility, Higher visual functions, Neuroimaging, Interventional neuroradiology, Tumors Financial Disclosures: The authors had no disclosures. Grant Support: This work was supported in part by National Eye Institute Vision Core Grant P30EY010608 and the Hermann Eye Fund. 2019 Annual Meeting Syllabus | 153