Surgical treatment of cerebellar hemangioblastomas

Genetics, Pathophysiology, and Current Challenges in Von Hippel-Lindau Disease Therapeutics

This review article focuses on von Hippel-Lindau (VHL) disease, a rare genetic disorder characterized by the development of tumors and cysts throughout the body. It discusses the following aspects of the disease.

GENETICS

VHL disease is caused by mutations in the VHL tumor suppressor gene located on chromosome 3. These mutations can be inherited or occur spontaneously. This article details the different types of mutations and their associated clinical features.

PATHOPHYSIOLOGY

The underlying cause of VHL disease is the loss of function of the VHL protein (pVHL). This protein normally regulates hypoxia-inducible factors (HIFs), which are involved in cell growth and survival. When pVHL is dysfunctional, HIF levels become elevated, leading to uncontrolled cell growth and tumor formation.

CLINICAL MANIFESTATIONS

VHL disease can affect various organs, including the brain, spinal cord, retina, kidneys, pancreas, and adrenal glands. Symptoms depend on the location and size of the tumors.

DIAGNOSIS

Diagnosis of VHL disease involves a combination of clinical criteria, imaging studies, and genetic testing.

TREATMENT

Treatment options for VHL disease depend on the type and location of the tumors. Surgery is the mainstay of treatment, but other options like radiation therapy may also be used.

CHALLENGES

This article highlights the challenges in VHL disease management, including the lack of effective therapies for some tumor types and the need for better methods to monitor disease progression. In conclusion, we emphasize the importance of ongoing research to develop new and improved treatments for VHL disease.

Pre-operative Embolization of a Cerebellar Hemangioblastoma Using Polyvinyl Alcohol (PVA) and Target Tetra 360 Detachable Coil

Due to its hypervascularity, hemangioblastoma, a rare primary central nervous system intracranial tumor, has been treated with pre-operative embolization prior to surgical resection. Here, we describe a case treated as such. A 37-year-old male presented with worsening chronic headache and right ear tinnitus was found to have a hypervascular, heterogeneous right cerebellar lesion suspicious for arteriovenous malformation or hemangioblastoma. He underwent polyvinyl alcohol (PVA) and Target Tetra 360 (Fremont, CA: Stryker Neurovascular) detachable coil embolization followed by complete tumor resection. Pathology was consistent with hemangioblastoma. He presented with complete resolution of his symptoms immediately post-operatively and at a two-week follow-up. Our case highlighted the importance of pre-operative embolization to help achieve complete tumor resection which is considered curative in the treatment of hypervascular hemangioblastoma. The Target Tetra 360 detachable coil embolization is another material that can be considered.

Bibliometric Analysis of the 100 Most Influential Hemangioblastoma Research Articles Illustrates Progress in Clinical Management and Room for Growth in Targeted Therapies

OBJECTIVE

This bibliometric analysis aims to identify the most impactful articles on hemangioblastoma (HB) and evaluate the trajectory of academic literature in the field.

METHODS

The authors performed a title search using the Web of Science database, with ("hemangioblastoma" OR "haemangioblastoma") as a search query. The top 100 cited articles from the years 1900-2020 were sorted by the descending order of the total citation count. The following variables were assessed for each article: title, first author name and institution, publication year, country of origin, citation count, citations per year, and journal impact factor.

RESULTS

The query yielded 1918 articles related to the topic of HB that were published between the years 1900 and 2020 in 42 unique journals. The most prolific decade of publication was the 2000s (35%), followed by the 1990s (33%) and the 1980s (11%). The average citation count was 88.3 (range, 47-426), and the mean number of citations per year was 3.74 (range, 0.660-17.8).

CONCLUSIONS

This is the first bibliometric analysis to evaluate the most influential HB publications. Though a majority of HBs are sporadic, these results suggest a research focus on von Hippel-Lindau-associated tumors. Despite established evidence for the potential to control HB growth with vascular endothelial growth factor inhibition, there are no known clinical trials underway for this investigation. There is a need for consistent treatment guidelines for asymptomatic HBs, as resection can prevent the development of neurological deficits. An improved understanding of the etiology of these neoplasms could promote the development of novel diagnostic and treatment methods.

A Challenge in Diagnosis of Cerebellar Hemangioblastoma

Hemangioblastomas are benign neoplasms, which are highly vascularized and have a slow-growing rate that typically affect the central nervous system; they account for about 1-2.5% of all intracranial tumors and for approximately 2-3% of all intramedullary neoplasms. We present a clinical case of cerebellar hemangioblastoma with six years of evolution, which illustrates the diagnostic difficulties that often arise, especially when the clinical and imaging characteristics escape those usually described and when other clinical findings appear as confounding factors. A 17-year-old female was initially admitted to the emergency department (ED) with a holocranial headache, gait imbalance, and vomiting. A brain magnetic resonance imaging (MRI) was done and a rounded lesion was detected in the left cerebellar hemisphere, hypointense in T1 and hyperintense in T2, with annular contrast enhancement. Several hypotheses for diagnosis were made, and the patient was subjected to several therapies, with periods of remission of symptoms interleaved with periods of worsening. After imaging suggestive of hemangioblastoma on routine brain MRI, the tumor was excised surgically and the histopathology confirmed the diagnosis. In the control brain MRI exams performed six and 24 months after surgery, no evidence of tumor recurrence was detected, and the patient remained asymptomatic. In conclusion, although these are rare neoplasms, it is essential to always consider hemangioblastomas in the differential diagnosis of cases with compatible clinical and radiological findings. A wrong or late diagnosis may lead to the use of unnecessary and harmful therapies as well as the appearance of potentially preventable complications if these tumors are handled correctly and timely.

Treatment Strategy for Giant Solid Hemangioblastomas in the Posterior Fossa: A Retrospective Review of 13 Consecutive Cases

OBJECTIVE

To analyze radiologic characteristics, treatment strategy, and treatment outcomes of posterior fossa giant solid hemangioblastomas (GSHBs; ≥4 cm in maximum diameter).

METHODS

We performed a retrospective study of 13 consecutive patients (9 male and 4 female patients; mean age, 57.5 ± 13.3 years; range, 24-76 years) with GSHB who underwent surgical resection at a single institution between 2002 and 2018. The median follow-up was 33 months (range, 12-120 months). For each patient, neuroimaging findings, operative record, and treatment outcome were reviewed.

RESULTS

Seven tumors (53.8%) were located within cerebellar hemispheres, 4 (30.8%) in proximity to the brainstem, 1 (7.7%) within the cerebellar vermis, and 1 (7.7%) in the cerebellopontine angle. The mean maximum diameter was 4.8 ± 0.8 cm (range, 4.0-6.7 cm). Gross total resection was achieved in 11 patients (84.6%), and near-total resection in 2 patients (15.4%). Surgical complications occurred in 5 patients (38.5%); persistent neurologic deficits occurred in 2 patients (15.4%). Estimated progression-free survival after surgery was 92.3%, 80.8%, and 80.8% at 1, 5, and 10 years, respectively, whereas the estimated 1-year, 5-year, and 10-year overall survival was 100%, 90%, and 90%, respectively.

CONCLUSIONS

GSHBs are surgically challenging. The current study shows that favorable outcome can be achieved for GSHBs in the cerebellar hemispheres and vermis. For those involving the brainstem, planned near-total resection or subtotal resection in a piecemeal fashion can be attempted if en bloc resection is judged to be infeasible, and further intervention can be considered as needed.

Oncologic causes of oculopalatal tremors: neurophysiology and treatment

Oculopalatal tremor (OPT) is an acquired pathology characterized by continuous and rhythmical soft palatal movements combined with pendular nystagmus. Aside from vascular lesions, oncological masses affecting the dentatorubro-olivary pathway can impair brainstem and/or cerebellar pathways, manifesting as dyssynchronous movement. In this review, we delve into the neurophysiology of OPT along with oncological causes and treatment options based on the most recent clinical trial data. This literature review includes medication treatment data from clinical trials enrolling individuals with features of OPT, including acquired pendular nystagmus (APN). Trials were deemed eligible for inclusion in this review if one or more participants had symptoms determined by the trial authors to be caused by OPT. Trials investigating the treatment of APN secondary to a separate cause, such as multiple sclerosis, were excluded from this review. Several early treatments failed to demonstrate a benefit for patients with APN due to OPT. Trials of anticholinergic agents were largely ineffective and poorly tolerated. Botulinum toxin A demonstrated improvement in APN symptoms. Most recently, trials including memantine and gabapentin have demonstrated success with attenuation of APN. Surgical modalities such as DBS have yet to show improvement, though with only a single case report as evidence. Oculopalatal tremor is a unique manifestation of posterior fossa tumors disrupting the Guillain-Mollaret triangle. Symptom control through medication management has had limited success attributed to poor response and medication intolerance. Surgical modalities like DBS may have an emerging role in OPT treatment by targeting dyssynchronous activity in the dentatorubro-olivary pathway.

Glioma-Targeted Therapeutics: Computer-Aided Drug Design Prospective

Amongst the several types of brain cancers known to humankind, glioma is one of the most severe and life-threatening types of cancer, comprising 40% of all primary brain tumors. Recent reports have shown the incident rate of gliomas to be 6 per 100,000 individuals per year globally. Despite the various therapeutics used in the treatment of glioma, patient survival rate remains at a median of 15 months after undergoing first-line treatment including surgery, radiation, and chemotherapy with Temozolomide. As such, the discovery of newer and more effective therapeutic agents is imperative for patient survival rate. The advent of computer-aided drug design in the development of drug discovery has emerged as a powerful means to ascertain potential hit compounds with distinctively high therapeutic effectiveness against glioma. This review encompasses the recent advances of bio-computational in-silico modeling that have elicited the discovery of small molecule inhibitors and/or drugs against various therapeutic targets in glioma. The relevant information provided in this report will assist researchers, especially in the drug design domains, to develop more effective therapeutics against this global disease.

Surgical Outcome of Large Solid Posterior Fossa Hemangioblastoma without Preoperative Embolization

BACKGROUND

 Large solid hemangioblastoma in the posterior fossa has an abundant blood supply as an arteriovenous malformation. The presence of adjacent vital neurovascular structures makes them vulnerable and difficult to operate. Complete surgical resection is always a challenge to the neurosurgeon.

MATERIAL AND METHOD

 We share the surgical difficulties and outcome in this case series of large solid hemangioblastomas without preoperative embolization as an adjunct. This study included five patients (three men and two women, with a mean age of 42.2 years). Preoperative embolization was attempted in one patient but was unsuccessful. All the patients have headache (100%) and ataxia (100%) as an initial symptom. A ventriculoperitoneal shunt was inserted in one case before definite surgery due to obstructive hydrocephalus. The surgical outcome was measured using the Karnofsky Performance Status (KPS) score.

RESULT

 The tumor was excised completely in all the cases. No intra- and postoperative morbidity occurred in four patients; one patient developed transient lower cranial nerve palsy. Mean blood loss was 235 mL, and no intraoperative blood transfusion was needed in any case. The mean follow-up period was 14.2 months. The mean KPS score at last follow-up was 80.One patient had a KPS score of 60.

CONCLUSION

 Our treatment strategy is of circumferential dissection followed by en bloc excision, which is the optimal treatment of large solid hemangioblastoma. The use of adjuncts as color duplex sonography and indocyanine green video angiography may help complete tumor excision with a lesser risk of complication. Preoperative embolization may not be needed to resect large solid posterior fossa hemangioblastoma, including those at the cerebellopontine angle location.

Solid Component Volume as a Proxy to Identify Distinct Hemangioblastoma Populations

BACKGROUND

Posterior fossa hemangioblastomas usually consist of a small solid nodule with a large cyst, while more rarely they present as a large solid mass with a small or absent cyst, which can be surgically challenging. We sought to investigate the potential existence of multiple distinct hemangioblastoma populations using tumor volumetric data as an indicator.

METHODS

We conducted a retrospective review of surgically treated hemangioblastomas between 2005 and 2019 in our unit, including clinical notes, preoperative magnetic resonance imaging volumetric analysis of the solid component of the tumor, and pathology. Finite Gaussian mixture modeling was applied on the solid component volume dataset to identify potential underlying Gaussian distributions with their associated characteristics. Nonparametric Mann-Whitney U tests were used to investigate significance of differences (P < 0.05) in solid component volume and different variables (Von Hippel-Lindau disease, extent of resection, outcome).

RESULTS

A total of 68 consecutive patients were included. Solid component volumes followed a multimodal distribution (median = 1287 mm³, interquartile range of 3428 mm³). The best-fit finite Gaussian mixture modeling model identified 3 statistically significant different (P = 0.001) potential mixture components: X₁ (219 ± 187 mm³)_, X₂ (2686 ± 1299 mm³), and X₃ (10,800 ± 5514 mm³). The second-best model detected 2 significantly different (P = 9.99e^-08) mixture components Y₁ (222 ± 189 mm³) and Y₂ (5391 ± 5094 mm³). A significant difference in solid component volume was found between patients with favorable and unfavorable outcome (P = 0.002).

CONCLUSIONS

This study has shown preliminary evidence that large solid hemangioblastomas may constitute a completely distinct population, rather than a variant of one large group of hemangioblastomas.