Adult Atypical Teratoid/Rhabdoid Tumors.
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.


METHODS
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.
Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Winona W
WW
Wu
Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Wenya Linda
WL
Bi
Department of Pathology, Division of Neuropathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Yun Jee
YJ
Kang
Department of Pathology, Division of Neuropathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Shakti H
SH
Ramkissoon
Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Sashank
S
Prasad
Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Helen A
HA
Shih
Center for Neuro-Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA.
David A
DA
Reardon
Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. Electronic address: idunn@partners.org.
Ian F
IF
Dunn
D001706:Biopsy; D001921:Brain / Q000473:pathology / Q000601:surgery; D059186:Chemoradiotherapy, Adjuvant; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics; D003131:Combined Modality Therapy; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics; D003937:Diagnosis, Differential; D020868:Gene Silencing; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D015192:Infratentorial Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D010911:Pituitary Neoplasms / Q000175:diagnosis / Q000235:genetics / Q000473:pathology / Q000601:surgery; D018335:Rhabdoid Tumor / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D000071796:SMARCB1 Protein; D013724:Teratoma / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D014157:Transcription Factors / Q000235:genetics
D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D005819:Genetic Markers; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; C109786:SMARCD1 protein, human; D014157:Transcription Factors
Atypical teratoid/rhabdoid tumor; Brain tumor; Clinical management; Genomics; Pineal tumor; Rhabdoid tumor