Faculty Bibliography

Pediatric neurosurgeons frequently care for children with traumatic scalp and skull injury. Foreign objects are often observed on imaging and may influence the clinician's decision-making process. The authors report on 2 cases of poorly visualized hair beads that had become embedded into the skull during blunt trauma. In both cases, skull radiography and CT scanning demonstrated depressed, comminuted fractures with poorly demonstrated spherical radiolucencies in the overlying scalp. The nature of these objects was initially unclear, and they could have represented air that entered the scalp during trauma. In one case, scalp inspection demonstrated no evidence of the bead. In the other case, a second bead was observed at the site of scalp laceration. In both cases, the beads were surgically removed, the fractures were elevated, and the patients recovered uneventfully. Radiolucent fashion accessories, such as hair beads, may be difficult to appreciate on clinical examination and may masquerade as clinically insignificant air following cranial trauma. If they are not removed, these foreign bodies may pose the risk of an infection. Pediatric neurosurgeons should consider hair accessories in the differential diagnosis of foreign bodies that may produce skull fracture following blunt trauma.

OBJECTIVE:Pilomyxoid astrocytoma (PMA) is a recently identified pediatric low-grade neoplasm that was previously classified as pilocytic astrocytoma (PA), yet demonstrates unique histological features and more aggressive behavior. These tumors have been shown to have significantly shorter progression-free and overall survival probability than classical low-grade astrocytomas, as well as a high rate of cerebrospinal fluid (CSF) dissemination. This paper describes the radiographic features of PMA. METHODS:Magnetic resonance imaging (MRI) was obtained for ten PMAs. Radiographic characteristics of the tumor were recorded in each case. All tissue samples were independently reviewed for confirmation of pathologic diagnosis. RESULTS:All tumors appeared well-circumscribed with no evidence of peritumoral edema or parenchymal infiltration on MRI. All tumors except one originated from the midline of the neuroaxis. Specifically, five tumors (50.0%) were located in the hypothalamic region, two (20.0%) were located in the spine, two (20.0%) were located in the dorsal brainstem and one was located in the right thalamus. Five tumors (50.0%) demonstrated solid composition, with the remaining five showing some cystic components. Mass effect, hydrocephalus and central necrosis were observed in 62.5, 50.0 and 0.0% of cases, respectively. Eight tumors (80%) were hyperintense on T1-weighted MRI. Seven tumors (77.8%) were hyperintense on T2-weighted MRI. All tumors were hyperintense on fluid attenuated inversion recovery (FLAIR) sequence and hypointense on diffusion weighted imaging (DWI). Upon contrast administration, six tumors (60.0%) enhanced heterogeneously and four tumors (40.0%) enhanced homogenously. CONCLUSION/CONCLUSIONS:Pilomyxoid astrocytoma is a well-circumscribed pediatric neoplasm that commonly originates from the midline of the neuroaxis and lacks peritumoral edema or central necrosis. It is critical to recognize the predominantly solid and well-circumscribed nature of the neoplasm to avoid confusion with an infiltrating astrocytoma.

Recent evidence suggests that suppression of the cellular immune response is often attributable to populations of functionally distinct T cells that act to down-regulate Ag-specific effector T cells. Using flow cytometry, we evaluated tumor-infiltrating lymphocytes (TIL) from patients undergoing neurosurgical resection of glioblastoma multiforme (GBM), metastatic lung carcinoma, and meningioma for markers known to be expressed on immunoregulatory T cells. Ex vivo phenotypic characteristics, cellular proliferation, and cytokine expression patterns were compared between T cell subsets found in the PBMC and within TIL from fresh tumor samples. Interestingly, nearly half of all T cells infiltrating GBM specimens were CD56(+) T cells, while much smaller percentages of similar cells were identified within metastatic lung tumors and meningiomas. CD56(+) T cells identified within GBM were not canonical, or "invariant," NKT cells, as they demonstrated diverse TCR expression, a primarily CD4 single-positive phenotype, and lack of CD1d reactivity. The percentage of CD56(+) T cells exhibiting evidence of proliferation within GBM was 3- to 4-fold higher than the proportion of proliferating CD56(-) T cells from these lesions. In addition, direct ex vivo analysis of cytokine expression by TIL from GBM demonstrated significant numbers of IL-4/IL-13 positive cells, cytokines that are integral in the cell-mediated repression of tumor immunity in experimental models. We propose that GBM has a unique capacity to recruit and activate CD4(+)CD56(+) T cells, a population that has not been previously described within human tumors.

Soft-tissue glomus tumors (or glomangiomas) are unrelated to neuroendocrine paragangliomas (glomus tympanicum, jugulare, and vagale). The authors present the first reported case of an orbital soft-tissue glomus tumor in a child. An 8-year-old girl developed rapidly progressive right-eye blindness, proptosis, and a sixth cranial nerve palsy. Magnetic resonance imaging demonstrated a homogeneously enhancing lesion extending from the right orbit through the superior orbital fissure to the cavernous sinus and middle cranial fossa. A biopsy specimen demonstrated the lesion to be a soft-tissue glomus tumor. Following angiography and embolization, a gross-total resection of the tumor was achieved. The patient was treated with adjuvant proton-beam radiotherapy. At 24 months follow-up her proptosis and sixth cranial nerve palsy had resolved and there was no evidence of tumor recurrence

OBJECTIVES/OBJECTIVE:Children with sickle cell anemia (SCA) and moyamoya syndrome carry a significant risk of ischemic stroke. Given the success of encephaloduroarteriosynangiosis (EDAS) or pial synangiosis in the treatment of moyamoya disease, the purpose of this study was to examine whether it reliably and durably protected children with SCA and moyamoya syndrome against cerebrovascular complications. METHODS:The authors retrospectively reviewed a series of 12 patients with SCA who developed clinical and/or radiological evidence of moyamoya syndrome and underwent EDAS. RESULTS:Eleven patients (92%) presented following a cerebrovascular accident (CVA), transient ischemic attack (TIA), or seizure. Magnetic resonance (MR) imaging or angiography suggested moyamoya vascular changes, and cerebral angiography confirmed the diagnosis in all 12 patients. At the time of surgery, the median age was 12.3 years (range 6.8-19.4 years). Ten (83%) of 12 patients had a history of CVA, and 4 of these patients were compliant with a transfusion protocol at the time of their CVA. Bilateral (7 patients) or unilateral (5 patients) EDAS was performed without complications. The mean follow-up period was 46.8 months (range 8.1-106 months). During the follow-up period, 2 patients (16.7%) suffered cerebrovascular events. One patient, who was stroke-free preoperatively, suffered a CVA 3 weeks after the procedure. The other patient suffered a single left lower-extremity TIA 18 months following right-sided EDAS. She returned to her neurological baseline condition and remains stable 53 months postoperatively. Seven patients underwent follow-up angiography or MR angiography, and evidence of revascularization was noted in all cases. At this time, no patient has developed progressive disease requiring a contralateral procedure after unilateral EDAS. CONCLUSIONS:The EDAS procedure is a safe and effective treatment option in patients with SCA who develop moyamoya syndrome.