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Open access

Stereotactic radiosurgery for the treatment of a distant recurrence of ependymoma on the optic nerve: illustrative case

Eduardo Orrego González, M. Beatriz Lopes, Gabriel Anibal Ramos, and Jason P Sheehan

BACKGROUND

Ependymomas rarely disseminate to other central nervous system areas distant from the original site. Stereotactic radiosurgery (SRS) provides high control rates for recurring ependymomas. The treatment of optic nerve tumors carries high morbidity, but SRS is an acceptable option to manage these cases to reduce risks.

OBSERVATIONS

The authors report the case of a 31-year-old male with a cervical spinal ependymoma who had a disseminated pattern of recurrence including the optic nerve after initial resection of the cervical lesion. The optic nerve tumor was treated with SRS, and the authors discuss the technical aspects of the treatment and its outcomes. At the last follow-up, the optic nerve tumor was controlled with SRS, and visual function was preserved.

LESSONS

High-grade ependymomas such as the one in the presented case can have unpredictable patterns of recurrence. SRS provides excellent control of the distant recurring ependymoma with a low complication profile given the location of the tumor in this case.

Open access

Novel combination of GammaTile cesium-131 brachytherapy with 5-aminolevulinic acid fluorescence–guided resection in the re-irradiation of pediatric recurrent high-grade glioma: illustrative case

Julian A. Gordon, Melisa Pasli, Cathleen M. Cook, Rainor Connor, Philip J. Boyer, Andrew W. Ju, K. Stuart Lee, Kathleen E. Knudson, and M. Sean Peach

BACKGROUND

Herein, the authors describe the successful utilization of 5-aminolevulinic acid (5-ALA) and the first case of GammaTile cesium-131 therapy in a pediatric patient with recurrent high-grade glioma. 5-ALA was utilized to optimize gross-total resection prior to GammaTile implantation. After conversion to an equivalent dose in 2-Gy fractions (EQD2), a composite was made of the GammaTile dose with the initial external beam radiotherapy. Two hypothetical plans consisting of a standard hypofractionated strategy for glioma reirradiation and a CyberKnife plan using GammaTile’s planning target volume were developed and likewise underwent EQD2 conversion and composite plan generation with the initial radiotherapy.

OBSERVATIONS

5-ALA was useful in achieving gross-total resection with no acute toxicity from the surgery or GammaTile irradiation. When compared with the hypothetical composite doses, GammaTile’s composite, axium point dose (D0.03cc) to the brainstem was 32.9 Gy less than the hypofractionated and the CyberKnife composite plans at 38.7 Gy and 40.2 Gy, respectively. The right hippocampus demonstrated a substantially reduced composite plan dose with GammaTile with a D0.03cc of 62.4 Gy versus 71.7 and 80.7 Gy for the hypofractionated and CyberKnife composite plans, respectively.

LESSONS

Utilization of 5-ALA and GammaTile therapy yielded clinically superior tumor debulking and effective radiotherapy dose localization with sparing of organs at risk, respectively.

Open access

Symptomatic radionecrosis after postoperative but not preoperative stereotactic radiosurgery in a single patient: illustrative case

Bryce J Laurin, Michael Straza, George Noid, Jennifer M Connelly, Wade M Mueller, Joseph Bovi, and Max O Krucoff

BACKGROUND

Standard of care for brain metastases involves stereotactic radiosurgery (SRS). For cases that also require surgery because of lesion size, edema, or neurological symptoms, whether to provide pre- or postoperative SRS has become a prevalent debate.

OBSERVATIONS

Herein, the unique case of a patient with brain metastases of the same pathology and similar size in two different brain locations at two different times is described. The patient underwent surgery with preoperative SRS for the first lesion and surgery with postoperative SRS for the second lesion. Although both treatments resulted in successful local control, the location that received postoperative SRS developed symptomatic and rapidly progressive radiation necrosis (RN) requiring a third craniotomy.

LESSONS

Large randomized controlled trials are ongoing to compare pre- versus postoperative SRS for the treatment of symptomatic brain metastases (e.g., study NRG-BN012). Recent interest in preoperative SRS has emerged from its theoretical potential to decrease rates of postoperative RN and leptomeningeal disease. This valuable case in which both therapies were applied in a single patient with a single pathology and similar lesions provides evidence supportive of preoperative SRS.

Open access

Rubrospinal activation during asleep subthalamic nucleus deep brain stimulation: a false localizing sign. Illustrative case

Devon L. Mitchell, John Pearce, Patrick King, and Sepehr Sani

BACKGROUND

Deep brain stimulation (DBS) can be a life-changing intervention for patients with Parkinson’s disease (PD), but its success is largely dependent on precise lead placement. The subthalamic nucleus (STN) is one of the most common surgical targets of DBS, but the close anatomical and physiological resemblance of the STN to the mediocaudal red nucleus renders these landmarks difficult to distinguish.

OBSERVATIONS

We present an atypical case in which targeted localization of the STN resulted in symptoms pathognomonic of rubrospinal tract (RST) stimulation. A 79-year-old female with a 12-year history of right-hand resting tremor due to medically refractory PD presented for asleep bilateral STN-DBS surgery. Right STN intraoperative testing revealed left hand and elbow flexion contractures, initially suggestive of corticospinal tract activation, despite imaging studies demonstrating reasonable lead placement in the central dorsolateral STN. The lead was moved anteromedially near the medial border of the STN, but stimulation at this location revealed similar but more robust flexor hand and arm contractures, without any extraocular muscle involvement. Thus, activation of the RST was suspected.

LESSONS

Isolated activation of the RST is possible during STN-DBS surgery. Its identification can help avoid false localization and suboptimal lead placement.

Open access

Rare clival localization of an eosinophilic granuloma: illustrative case

Martin E. Weidemeier, Steffen Fleck, Werner Hosemann, Silke Vogelgesang, Karoline Ehlert, Holger N. Lode, and Henry W. S. Schroeder

BACKGROUND

Eosinophilic granuloma (EG) belongs to the family of Langerhans cell histiocytosis (LCH) and is considered to be a benign disease typically found in children younger than 15 years of age. Here, the authors describe an EG of unusual localization and clinical presentation.

OBSERVATIONS

The authors report a 9-year-old girl with an EG presenting as an osteolytic lesion of the clivus. After transsphenoidal resection and histological confirmation, adjuvant chemotherapy was initiated. Presenting signs and symptoms were weight loss, episodic grimacing, and moderate ballism-like movements. After a follow-up-period of 32 months, the patient presented with a total resolution of initial symptoms and no further tumor growth.

LESSONS

Although these lesions are rare, one should consider EG as a differential diagnosis when confronted with osteolytic lesions of the clivus.

Open access

White epidermoid cyst transformation after stereotactic radiosurgery: illustrative case

Hideki Matsumoto, Yuki Shinya, Satoru Miyawaki, Masahiro Shin, Satoshi Koizumi, Daisuke Sato, Munetoshi Hinata, Masako Ikemura, Satoshi Kiyofuji, Taich Kin, Mototaro Iwanaga, Masahiro Shimizu, Hirofumi Nakatomi, and Nobuhito Saito

BACKGROUND

White epidermoid cysts (WECs) are a rare type of epidermoid cyst with atypical radiological features. The epidemiological aspects and mechanisms of their onset remain unknown. Herein, the authors report a unique case of WEC transformation from a typical epidermoid cyst after stereotactic radiosurgery (SRS), confirmed by radiological and pathological findings.

OBSERVATIONS

The case involved a 78-year-old man with a history of 2 surgeries for a left cerebellopontine angle typical epidermoid cyst 23 years earlier and SRS using the CyberKnife for recurrent trigeminal neuralgia (TN) 14 years earlier. The tumor with high intensity on T1-weighted imaging, low intensity on T2-weighted imaging, without restriction on diffusion-weighted imaging had gradually enlarged after SRS. Therefore, a salvage surgery was performed via a left suboccipital craniotomy, and the intraoperative findings showed a cyst with a brown, viscous liquid component, consistent with those of WECs. Histopathologically, keratin calcification and hemorrhage were identified, leading to a diagnosis of WEC. The postoperative course was uneventful, and the TN resolved. No tumor recurrence was recorded at 2 years postoperatively.

LESSONS

To the best of the authors’ knowledge, this is the first world case of WEC transformation from a typical epidermoid cyst after SRS, confirmed by radiological and pathological findings. Radiation effects could have been involved in this transformation.

Open access

Stereotactic radiosurgery for recurrent skull base polymorphous adenocarcinoma invading the cavernous sinus: illustrative case

Yurie Rai, Motoyuki Umekawa, Yuki Shinya, Hirotaka Hasegawa, Atsuto Katano, Kenji Kondo, Aya Shinozaki-Ushiku, and Nobuhito Saito

BAKGROUND

Polymorphous adenocarcinomas (PACs) are rare tumors arising from the salivary glands. Radical resection and postoperative radiotherapy are the mainstays of treatment. However, complete tumor resection is not always achievable when the tumor invades the skull base. Stereotactic radiosurgery (SRS) could be a less invasive alternative for treating skull base PACs.

OBSERVATIONS

A 70-year-old male with a history of surgery for a right palatine PAC presented with right visual impairment, diplopia, and ptosis. Imaging studies revealed tumor recurrence invading the right cavernous sinus (CS). SRS using a gamma knife was performed for this recurrence, prescribing a marginal dose of 18 Gy at a 50% isodose line. Five months after SRS, his symptoms were relieved, and the tumor was well-controlled for 55 months without any adverse events.

LESSONS

To the best of the authors’ knowledge, this is the world’s first case of recurrent skull base PAC invading the CS that was successfully treated with salvage SRS. Thus, SRS may be an applicable treatment option for skull base PACs.

Open access

Dorsal medullary cavernous hemangioma presenting as obstinate hiccups and its surgical treatment: illustrative case

Sumirini Puppala, Abhijit Acharya, Atmaranjan Dash, and Surjyaprakash S. Choudhury

BACKGROUND

Hiccups are characterized by involuntary, intermittent, repetitive, myoclonic, and spasmodic contractions of the diaphragm. Hiccups are termed “intractable” when they last for over 1 month.

OBSERVATIONS

A rare case of intractable hiccups due to an uncommon location of cavernous hemangioma in the dorsal medulla is illustrated. With respect to the management, surgical excision was performed, and postsurgical complete recovery was witnessed, which has been reported only in six cases worldwide to date.

LESSONS

A mechanism of the hiccups reflex arc is discussed in detail with special reference to the need for equal emphasis on evaluating central nervous system causes and peripheral etiologies for pertinent hiccups.

Open access

Treatment of adverse radiation effects with Boswellia serrata after failure of pentoxifylline and vitamin E: illustrative cases

Ronald E. Warnick

BACKGROUND

Adverse radiation effects (AREs) can occur after stereotactic radiosurgery (SRS), and symptomatic cases are often treated with corticosteroids, pentoxifylline, and vitamin E. The supplement 5-Loxin (Boswellia serrata) is an extract of Indian frankincense that inhibits vascular endothelial growth factor expression and has been shown to reduce perilesional edema in brain tumor patients undergoing fractionated radiation.

OBSERVATIONS

Three patients underwent SRS for meningioma or metastasis and developed symptomatic AREs at 4 to 8 months. They were initially treated with corticosteroids, pentoxifylline, and vitamin E with transient improvement followed by recurrent neurological symptoms and imaging findings as steroids were tapered off. All patients were rescued by the administration of 5-Loxin with resolution of neurological symptoms and imaging changes, discontinuation of steroids, and no medication side effects.

LESSONS

The author’s early experience with 5-Loxin has been encouraging, and this supplement has become the author’s first-line treatment for acute radiation effects after SRS. The author reserves bevacizumab for significant mass effect or failure of oral therapy. 5-Loxin has many advantages including low cost, ease of use, and patient tolerability. More experience is needed to confirm the role of 5-Loxin in the upfront treatment of AREs.

Open access

Dural arteriovenous fistulas misdiagnosed as intracranial neoplasms: illustrative case

Tobias Rossmann, Michael Veldeman, Ville Nurminen, Rahul Raj, and Mika Niemelä

BACKGROUND

Dural arteriovenous fistulas (dAVF) may induce imaging findings attributable to various disease entities including malignant neoplasms. In these cases, diagnosis and adequate treatment are often delayed and patients may be exposed to spurious treatments in addition to the risks inherent to an untreated dAVF with cortical venous drainage.

OBSERVATIONS

The authors report a case of a patient referred for surgical treatment of a supratentorial high-grade glioma. Thorough review of imaging data challenged the initial radiological diagnosis and led to proper angiographic workup. As a result, a high-grade dAVF was confirmed and successfully embolized. In addition to this case, we provide an extensive literature review on dAVF initially diagnosed as cerebral neoplasms, including clinical, imaging and follow-up data.

LESSONS

The literature provides diagnostic criteria for dAVF on magnetic resonance imaging; however, those criteria may be only partly applicable in many cases. Misdiagnosis of a neoplasm due to dAVF has been reported but remains rare, especially in supratentorial lesions. Digital subtraction angiography should be pursued to rule out an underlying vascular pathology if any doubt. This may prevent unnecessary interventions such as biopsies, pharmacological treatment and a delay in dAVF treatment, given its associated risk of hemorrhage and nonhemorrhagic neurological deficits.