Wu Winona W, Bi Wenya Linda, Kang Yun Jee, Ramkissoon Shakti H, Prasad Sashank, Shih Helen A, Reardon David A, Dunn Ian F
Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Department of Pathology, Division of Neuropathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
World Neurosurg. 2016 Jan;85:197-204. doi: 10.1016/j.wneu.2015.08.076. Epub 2015 Sep 4.
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.
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).
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.
非典型畸胎样/横纹肌样瘤（AT/RTs）是高度恶性肿瘤，在成人中很少见。由于AT/RTs的组织学结构复杂，这些肿瘤的鉴别诊断颇具挑战性，且越来越依赖于肿瘤细胞中特征性SMARCB1/INI1失活的证明。
一名51岁男性因帕里诺德综合征和脑积水出现复视、嗜睡和记忆缺陷。磁共振成像显示一个T2高信号且均匀强化的顶盖肿块，延伸至松果体区域。初步活检提示为世界卫生组织二级黏液乳头型星形细胞瘤。然而，随后的根治性切除显示为AT/RT，通过免疫组织化学染色以及阵列细胞遗传学分析观察到SMARCB1/INI1缺失。分子谱分析显示RHPN2（L385I）、MDM4（D396G）、FLT3（V194M）和NPRL3（D53N）存在额外突变。
现代病理学诊断越来越多地整合分子数据以进行确诊和预后评估。我们报告了一例成人患者中罕见的顶盖AT/RT病例，并报告了该肿瘤亚型中一些以前未被识别的新突变，以及典型的SMARCB1/INI1缺失。对这些新变异的进一步研究可能会增进对AT/RTs发病机制的理解。
