Faculty Bibliography

BACKGROUND:Intraosseous petrous apex schwannomas are an exceedingly rare entity; little is known about their epidemiology, natural history, and post-operative outcomes. CASE DESCRIPTION/METHODS:Here, we present the fourth known case of a primary intraosseous schwannoma of the petrous apex: a 68-year-old woman presenting with diplopia, facial numbness, progressive intermittent vertigo, tinnitus, diminished hearing, and ataxia. She underwent a transtemporal approach for subtotal resection of the tumor with subsequent stereotactic radiosurgery. CONCLUSIONS:Our two-year follow-up demonstrates slow growth and success of multimodal management in the treatment of these tumors. We review the three prior reports of petrous apex schwannomas, and identify unifying radiographic and clinical characteristics in order to aid in future diagnostic considerations of lesions of the petrous apex.

BACKGROUND:Hemangiopericytomas (HPCs) are rare vascular tumors that resemble meningiomas on imaging and have a high rate of local recurrence and metastases. There remains a paucity of data to guide management decisions of intraspinal dissemination of HPCs in the literature, and none specifically related to anaplastic HPCs. CASE DESCRIPTION/METHODS:We report a case of a 34-year-old woman with locally and distantly recurrent anaplastic HPC (World Health Organization grade III). She initially presented with tinnitus in her right ear. A well-circumscribed, contrast-enhancing lesion was identified in the right cerebellopontine angle. Treatment consisted of subtotal resection and postoperative radiation therapy (RT) to a dose of 60 Gy in 30 fractions. After a 3-year disease-free interval, 7 lesions recurred intra- and extracranially. The extracranial lesions were drop metastases of the original HPC through the cerebrospinal fluid into the spinal canal. Of note, fluorodeoxyglucose positron emission tomography (PET)/computed tomography scan was not sensitive enough to detect these new lesions. The intracranial recurrence was on the edge of the prior radiotherapy field, representing a marginal failure having received less than 50 Gy. The intracranial recurrences were treated with salvage gamma knife stereotactic radiosurgery (SRS) with local control. She underwent intradural extramedullary hemilaminectomy of a thoracic spine metastasis followed by fractionated proton beam therapy (PBT) with a boost to unresected lesions. Within a few months of PBT, she became pregnant. Pregnancy did not affect recurrence or ameliorate tumor growth. CONCLUSIONS:This case report discusses the role genetics, adjuvant RT, SRS, magnetic resonance imaging, and PET scan played in this unique clinical scenario of anaplastic HPC.

Background: Surgical resection of pituitary adenomas is associated with a 10 to 30% rate of temporary diabetes insipidus with ~50% resolving within 1 week and 80% resolving at 3 months.[1] Adrenal insufficiency occurs in ~ 5 % of patients and can result in an Addisonian crisis if left undiagnosed postoperatively.[1] [2] Many studies have been performed looking at readmission rates after pituitary surgery. A review of over 1,200 cases demonstrated a readmission rate of 8.5% with the most common cause being hyponatremia (29.5%).[3] To reduce the rate of readmission for hyponatremia, some groups have demonstrated the effective use of outpatient fluid restriction criteria during the first week post-op.[4] These guidelines are intended for the management of standard postoperative hormonal fluctuations which do not necessitate endocrine consultation during hospitalization.
Objective(s): Retrospectively evaluate patients undergoing endoscopic endonasal resection of pituitary adenomas to identify areas for quality improvement through the development of more standardized postoperative guidelines.
Method(s): A retrospective review of 75 patients who underwent endoscopic endonasal resection of pituitary adenomas at a single academic center from 2013 to 2018. We evaluated the average length of stay, number of laboratory studies performed, need for hormone supplementation long term and short term, rate of gross-total resection, rate of cerebrospinal fluid leak, rate of infection, and 30-day readmission rate ([Table 1]). From this, we have developed a change in guidelines aimed at reducing length of stay, redundant laboratory studies, and reduced rate of readmission.
Conclusion(s): Although our current outcomes for resection of pituitary adenoma are on par with published data, we have identified areas of possible quality improvement which have since been implemented

Epigenetic patterns on the level of DNA methylation have already shown to separate clinically relevant subgroups of meningiomas. Based on a reference set (Sahm et al., Lancet Oncol 2017), an epigenetic meningioma classifier employing DNA methylation patterns is made available through molecularneurpathology.org. We now set out to identify prognostic implications of epigenetic modification on the proteome level, particularly modifications of histones. First focus was on H3K27 trimethylation (H3K27me3). H3K27me3 was assessed by immunohistochemistry on 232 meningiomas. In 194 cases, trimethylation was detected in tumor cells. In 25 cases, staining was limited to vessels while all tumor cells were negative. Finally, 13 cases yielded equivocal staining patterns. Reduced abundance of H3K27me3 in cases with staining limited to vessels was confirmed by mass spectrometry on a subset of cases. Lack of staining for H3K27me3 in all tumor cells was significantly associated with more rapid progression (p=0.009). In line, H3K27me3 negative cases were associated with a DNA methylation pattern of the more aggressive types among the recently introduced DNA methylation groups. Also, NF2 and SUFU mutations were enriched among cases with lack of H3K27me3 in tumor cells (p<0.0001 and p=0.029, respectively). H3K27me3 staining pattern added significant prognostic insight in WHO grade II cases and in the compound subset of WHO grade I and II cases (p=0.04 and p=0.007, respectively). However, it did not further stratify within WHO grade III cases. Collectively, this data indicate that epigenetic modifications beyond DNA methylation are involved in the aggressiveness of meningioma. It also suggests that H3K27me3 immunohistochemistry might be a useful adjunct in meningioma diagnostics, particularly for cases with WHO grade II histology or at the borderline between WHO grade I and II. Ongoing studies evaluate the role of histone marks other than H3K27me3 and consequences on the proteomic composition of meningioma cells by high-throughput mass spectrometry

OBJECTIVECerebral venous sinus thrombosis (CVST) is a known complication of surgeries near the major dural venous sinuses. While the majority of CVSTs are asymptomatic, severe sinus thromboses can have devastating consequences. The objective of this study was to prospectively evaluate the true incidence and risk factors associated with postoperative CVST and comment on management strategies.METHODSA prospective study of 74 patients who underwent a retrosigmoid, translabyrinthine, or suboccipital approach for posterior fossa tumors, or a supratentorial craniotomy for parasagittal/falcine tumors, was performed. All patients underwent pre- and postoperative imaging to evaluate sinus patency. Demographic, clinical, and operative data were collected. Statistical analysis was performed to identify incidence and risk factors.RESULTSTwenty-four (32.4%) of 74 patients had postoperative MR venograms confirming CVST, and all were asymptomatic. No risk factors, including age (p = 0.352), BMI (p = 0.454), sex (p = 0.955), surgical approach (p = 0.909), length of surgery (p = 0.785), fluid balance (p = 0.943), mannitol use (p = 0.136), tumor type (p = 0.46, p = 0.321), or extent of resection (p = 0.253), were statistically correlated with thrombosis. All patients were treated conservatively, with only 1 patient receiving intravenous fluids. There were no instances of venous infarctions, hemorrhages, or neurological deficits. The rate of CSF leakage was significantly higher in the thrombosis group than in the nonthrombosis group (p = 0.01).CONCLUSIONSThis prospective study shows that the radiographic incidence of postoperative CVST is higher than that previously reported in retrospective studies. In the absence of symptoms, these thromboses can be treated conservatively. While no risk factors were identified, there may be an association between postoperative CVST and CSF leak.

Background: Assessment of preoperative imaging is important for operative planning of meningioma resection. A hyperintense rim on T2-weighted (T2W) MRI is frequently thought to represent a CSF cleft between the tumor and the brain, suggesting a clean arachnoid plane. However, brain invasion (loss of arachnoid plane) is often encountered instead. We sought to further characterize this radiographic finding and identify correlates with intraoperative brain invasion and pathology in patients undergoing meningioma resection. Methods: Retrospective review of 42 patients (mean age: 54.2 years, SD: 13.0, 76% female) who underwent meningioma resection between 2013 and 2016 at a single institution. Demographic variables and pathology results were recorded. Radiographic variables on preoperative MRI included presence and size of a hyperintense rim on T2W MRI, a contrast-enhancing rim on fluid-attenuated inversion recovery (FLAIR), and adjacent edema. Operative reports were reviewed for identification of loss of arachnoid plane (brain invasion) noted during surgery. Radiographic findings were then correlated with brain invasion using nonparametric statistics. Results: Of 42 meningiomas resected, there were 29 (69%) WHO Grade I, 12 (29%) WHO Grade II, and 1 (2%) WHO Grade III. Twenty-three tumors (55%) were located at the skull base. On preoperative T2WI, 36 (86%) of meningiomas demonstrated a hyperintense cleft with a mean width of 2.86 mm (SD: 1.66) and 16 had adjacent edema. Twenty-six meningiomas demonstrated a contrast-enhancing rim on FLAIR with a mean width of 2.85 mm (SD: 1.06) and 28 meningiomas exhibited a rim that was both T2 hyperintense and enhancing on FLAIR. Intraoperatively, 24 (57%) of meningiomas were found to have partial or complete loss of an arachnoid plane between the tumor and adjacent brain parenchyma. Both a hyperintense T2 cleft and enhancing FLAIR rim were associated with loss of arachnoid plane (p=0.004 for T2, <0.001 for FLAIR, <0.001 for combined). Conclusion: Preoperative MRI of meningiomas often identifies a T2 hyperintense rim frequently thought to represent a CSF cleft. A correlation with enhancement on FLAIR and intraoperative loss of arachnoid plane suggests this may be a useful marker of brain invasion and could aid in operative planning and risk assessment

Background/UNASSIGNED:While effective for the repair of large skull base defects, the Hadad-Bassagasteguy nasoseptal flap increases operative time and can result in a several-week period of postoperative crusting during re-mucosalization of the denuded nasal septum. Endoscopic transsphenoidal surgery for pituitary adenoma resection is generally not associated with large dural defects and high-flow cerebrospinal fluid (CSF) leaks requiring extensive reconstruction. Here, we present the posterior nasoseptal flap as a novel technique for closure of skull defects following endoscopic resection of pituitary adenomas. This flap is raised in all surgeries during the transnasal exposure using septal mucoperiosteum that would otherwise be discarded during the posterior septectomy performed in binostril approaches. Methods/UNASSIGNED:We present a retrospective, consecutive case series of 43 patients undergoing endoscopic transsphenoidal resection of a pituitary adenoma followed by posterior nasoseptal flap placement and closure. Main outcome measures were extent of resection and postoperative CSF leak. Results/UNASSIGNED:The mean extent of resection was 97.16 ± 1.03%. Radiographic measurement showed flap length to be adequate. While a defect in the diaphragma sellae and CSF leak were identified in 21 patients during surgery, postoperative CSF leak occurred in only one patient. Conclusions/UNASSIGNED:The posterior nasoseptal flap provides adequate coverage of the surgical defect and is nearly always successful in preventing postoperative CSF leak following endoscopic transsphenoidal resection of pituitary adenomas. The flap is raised from mucoperiosteum lining the posterior nasal septum, which is otherwise resected during posterior septectomy. Because the anterior septal cartilage is not denuded, raising such flaps avoids the postoperative morbidity associated with the larger Hadad-Bassagasteguy nasoseptal flap.