Chordomas are malignant neoplasms that typically arise in the axial spine and primarily affect adults. When chordomas arise in pediatric patients they are more likely to display unusual histological features and aggressive behavior. We noted the absence of SMARCB1/INI1 expression by immunohistochemistry in an index case of poorly differentiated chordoma of the sacrum, leading us to further examine SMARCB1/INI1 expression as well as that of brachyury, a highly specific marker of notochordal differentiation, in 3 additional poorly differentiated chordomas of the clivus, 10 typical chordomas, and 8 atypical teratoid/rhabdoid tumors (AT/RTs). All 4 poorly differentiated chordomas and all AT/RTs lacked nuclear expression of SMARCB1/INI1, while the 10 typical chordomas maintained strong nuclear SMARCB1/INI1 immunoreactivity. All 10 typical and 4 poorly differentiated chordomas expressed brachyury; all 8 AT/RTs were brachyury immunonegative. Cytogenetic evaluation utilizing FISH probes near the SMARCB1/INI1 locus on chromosome 22q was also performed in all of the poorly differentiated chordomas in this series. Three of the four poorly differentiated chordomas had evidence for deletion of this region by FISH. Analysis of the SMARCB1/INI1 gene sequence was performed using formalin-fixed paraffin-embedded tissue in all cases and no point mutations were observed. In summary, all poorly differentiated chordomas in this series showed the absence of SMARCB1/INI1 expression, and were reliably distinguished from AT/RTs, clinically by their characteristic primary sites of origin and pathologically by strong nuclear brachyury expression. Our findings reveal a likely role for SMARCB1/INI1 in a subset of chordomas with aggressive features.

Multisession SRS treatment of vestibular schwannomas results in an excellent rate of tumor control. The hearing, trigeminal nerve, and facial nerve function preservation rates reported here are promising.

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In contrast to sagittal craniosynostosis, the role of endoscopic, minimally invasive approaches in the treatment of metopic craniosynostosis with resulting trigonocephaly is not as well defined. We reviewed the senior authors' (H.M. and S.C.) clinical experience in the treatment of children with metopic craniosynostosis using a variety of endoscopic and open techniques. Thirty-three patients were treated at a single institution during a 5-year period with between 3 and 8 years of follow-up. Sixteen patients underwent 3 variations of endoscopic approaches, and 17 patients had open fronto-orbital advancement. Clinical parameters of the 2 groups were examined including age at surgery, blood loss, operative time, transfusion volume, hospital stay, complications, use of postoperative cranial banding, and the need for reoperation for persistent deformity. The various endoscopic and open techniques used by the authors in the treatment of metopic craniosynostosis are discussed in detail, including rational for individual technique selection and preliminary impressions regarding clinical outcome.