True anaplastic oligoastrocytoma with dual genotype: illustrative case.

BACKGROUND: The revised fourth edition of the World Health Organization classification of central nervous system tumors was published in 2016. Based on this classification, one of the infiltrating glioma entities named "oligoastrocytoma/anaplastic oligoastrocytoma" is discouraged. It is proposed that these mixed gliomas should be classified as diffuse astrocytoma/anaplastic astrocytoma or oligodendroglioma/anaplastic oligodendroglioma when analyzing their genetic alteration. OBSERVATIONS: A 78-year-old female underwent brain computed tomography (CT) because of a traffic accident. Cranial CT revealed a brain tumor in the left temporoparietal lobe; therefore, she was hospitalized. She underwent awake craniotomy. After the operation, she was treated with only local radiotherapy; the authors could not prescribe temozolomide, because she had had levetiracetam-induced pancytopenia. The remaining tumor neuroradiologically disappeared, and she was alive 40 months after the operation without tumor recurrence. LESSONS: Histopathologically, this tumor was diagnosed as an anaplastic oligoastrocytoma with a distinct dual phenotype of astrocytoma and oligodendroglioma components. Genetically, these two components revealed astrocytoma and oligodendroglioma genotypes, respectively. Therefore, the authors considered the integrated diagnosis of the temporal tumor as a true anaplastic oligoastrocytoma with a dual genotype. Interestingly, this case also included an area composed of spindle to oval neoplastic cells that revealed intermediate genetic alterations between astrocytomas and oligodendrogliomas.

Pilocytic astrocytoma of the optic nerve with intracystic hemorrhage in an adult: illustrative case.

BACKGROUND: Optic pathway gliomas are uncommon, accounting for 3-5% of childhood brain tumors, and are mostly classified as pilocytic astrocytomas (PAs). PAs of the optic nerve are particularly rare in adults. OBSERVATIONS: The authors presented the case of PA of the left optic nerve in a 49-year-old woman along with detailed pathological and molecular analyses and sequential magnetic resonance imaging. The tumor had progressed during 5 years of follow-up along with cyst formation and intracystic hemorrhage; it had a thick capsule and contained xanthochromic fluid. The boundary between tumor and optic nerve was unclear. B-type Raf kinase (BRAF) V600E point mutations or translocations, IDH1-R132H mutations, loss of alpha-thalassemia/mental retardation X-linked, and 1p/19q codeletion were negative. LESSONS: BRAF alterations in pediatric PAs of the optic nerve are less frequent than those observed in PAs in other lesions; the same molecular pattern was observed in the adult case, without changes in BRAF. Surgical management should be indicated only in cases with severely impaired vision or disfigurement because there is no clear border between the tumor and optic nerve. Further discussion is needed to optimize the treatment for adult optic pathway gliomas, including radiotherapy, chemotherapy, and molecular-targeted therapies, in addition to surgical intervention.

Intracranial tuberculoma: a rare complication of extrapulmonary tuberculosis. Illustrative case.

BACKGROUND: Intracranial tuberculomas are rare entities commonly seen only in low- to middle-income countries where tuberculosis remains endemic. Furthermore, following adequate treatment, the development of intracranial spread is uncommon in the absence of immunosuppression. OBSERVATIONS: A 22-year-old man with no history of immunosuppression presented with new-onset seizures in the setting of miliary tuberculosis status post 9 months of antitubercular therapy. Following a 2-month period of remission, he presented with new-onset tonic-clonic seizures. Magnetic resonance imaging demonstrated interval development of a mass concerning for an intracranial tuberculoma. After resection, pathological analysis of the mass revealed caseating granulomas within the multinodular lesion, consistent with intracranial tuberculoma. The patient was discharged after the reinitiation of antitubercular medications along with a steroid taper. LESSONS: To the best of the authors' knowledge, this case represents the first instance of intracranial tuberculoma occurring after the initial resolution of a systemic tuberculosis infection. The importance of retaining a high level of suspicion when evaluating these patients for seizure etiology is crucial because symptoms are rapidly responsive to resection of intracranial tuberculoma masses. Furthermore, it is imperative for surgeons to recognize the isolation steps necessary when managing these patients within the operating theater and inpatient settings.

Primary germinoma of the medulla oblongata: illustrative case.

BACKGROUND: Primary central nervous system germinomas of the medulla oblongata are extremely rare and usually have been found in young female Asian patients. The authors present an illustrative case of a patient who presented with severe medullary and posterior cord syndrome, the first South American case published to date, to the authors' knowledge. OBSERVATIONS: Initially, the radiological differential diagnosis did not include this entity. The lesion was located at the obex and exhibited a well-delineated contrast enhancement without hydrocephalus. An emergency decompressive partial resection following functional limits was performed. After histological confirmation, radiotherapy was indicated, with complete remission achieved at a 6-month follow-up. The patient, however, continued to have a severe proprioceptive disorder. The literature review identified 21 other such patients. The mean age for this location was 23 years, with a strong female and Asian origin predilection. All tumors exhibited contrast enhancement, and only one presented with hydrocephalus. LESSONS: In the absence of elevated tumor markers, radiological clues such as a well-delineated, contrast-enhanced lesion arising from the obex, without hydrocephalus, associated with demographic features such as young age, female sex, and Asian heritage, should evoke a high level of suspicion for this diagnosis. Gross total resection must not be attempted, because this tumor is potentially curable with high-dose radiotherapy.

Minimally invasive endoscopic fenestration of a spinal arachnoid cyst in a child with tetrasomy 18p: illustrative case.

BACKGROUND: Spinal arachnoid cysts (SAC) are rare, especially in children. Patients can be asymptomatic or present symptoms of spinal cord compression. In this latter case, surgery is indicated to relieve the compression. Different surgical techniques have been described to treat these cysts, endoscopic or endoscopy-assisted fenestration being the least invasive. Tetrasomy 18p describes the condition in which two copies of the short arms of chromosome 18 are present. It is an extremely rare pathology with a variable phenotype, including 100% of cases cognitive impairment and developmental delay. Different central nervous system (CNS) abnormalities have been found in these patients. OBSERVATIONS: The authors describe the case of a 3-year-old boy with a tetrasomy 18p and a wide spinal arachnoid cyst that received an endoscope-assisted treatment with a significantly improved motor outcome. LESSONS: Tetrasomy 18p is an extremely rare pathology and different CNS abnormalities have been described in association with, but to date spinal arachnoid cyst has never been reported. These children typically show global hypotonia and cognitive impairment. The authors recommend a thorough neurological assessment with cranio-spinal magnetic resonance imaging to rule out any possible malformation that could be improved by surgery.

Simultaneous intracranial and testicular germ cell tumors: illustrative case.

BACKGROUND: Simultaneous intracranial and testicular germ cell tumors (GCTs) are extremely rare, leading to a lack of adequate experience in their treatment. Therefore, the authors report a case of this kind of GCT. OBSERVATIONS: A 5-year-old boy was admitted to the hospital with headache and vomiting. Computed tomography and magnetic resonance imaging suggested the possibility of a GCT in the pineal region. The value of the serum tumor marker alpha-fetoprotein (AFP) was 5,396.1 µg/L, and ß-human chorionic gonadotropin levels were within the normal range. Subsequently, the tumor was removed, and the final pathological result was a mixed GCT. Therefore, chemotherapy and radiation were added. However, the authors found a testicular tumor on ultrasound at the same time, and pathology after surgery suggested a mature cystic teratoma. Following treatment, the patient recovered well, and AFP levels dropped to normal values. LESSONS: To the authors' knowledge, this report is the fourth case of simultaneous intracranial and testicular GCTs and the first case of a simultaneous mixed GCT in the pineal region and mature teratoma of the testis. A combination of surgery, chemotherapy, and radiation therapy for mixed GCTs in the pineal region and surgical excision for testicular reproductive cell tumors are effective in these patients, but long-term monitoring is required.

Intradural plasmacytoma originating from the filum terminale in the setting of multiple myeloma: illustrative case.

BACKGROUND: Multiple myeloma (MM) has the propensity to spread to vertebral bodies; however, extramedullary plasmacytomas involving the central nervous system are extremely rare. OBSERVATIONS: The authors report the first intradural extramedullary plasmacytoma in the lumbar region of the spine in a patient with preexisting MM. They present a 50-year-old female with severe back and radicular pain and progressive neurological deficit. LESSONS: MM is typically treated with chemotherapy and radiation therapy. However, in this unique case, resection proved to be a key part of treatment.

Herpes simplex meningitis after vestibular schwannoma surgery: illustrative case.

BACKGROUND: Herpes is the most common cause of viral encephalitis in the young population. Herpes meningitis following brain surgery is very rare, however. Only a few cases are reported in the literature, and only one concerned an infection after vestibular schwannoma surgery. OBSERVATIONS: The authors report a case of a 44-year-old patient who developed severe herpes meningitis a few days after removal of a large cystic vestibular schwannoma. LESSONS: Herpes simplex virus meningitis following a posterior fossa surgery must be considered when patients develop atypical symptoms a few days after surgery.

Intraoperative contrast-enhanced ultrasound for intramedullary spinal neoplasms: patient series.

BACKGROUND: Primary intramedullary spinal tumors cause significant morbidity and death. Intraoperative ultrasound as an adjunct for localization and monitoring the extent of resection has not been systematically evaluated in these patients; the effectiveness of intraoperative contrast-enhanced ultrasound (CEUS) remains almost completely unexplored. OBSERVATIONS: A retrospective case series of patients at a single institution who had consented to the off-label use of intraoperative CEUS was identified. Seven patients with a mean age of 52.8 ± 15.8 years underwent resection of intramedullary tumors assisted by CEUS performed by a single attending neurosurgeon. Histopathological evaluation revealed 3 cases of hemangioblastoma, 1 case of pilocytic astrocytoma, 2 cases of ependymoma, and 1 case of subependymoma. Contrast enhancement correlated with gadolinium enhancement on preoperative magnetic resonance imaging. Intraoperative CEUS facilitated precise lesion localization and myelotomy planning. Dynamic CEUS studies were useful in demonstrating the blood supply to lesions with a dominant vascular pedicle. Regardless of contrast uptake, the differential enhancement between spinal cord tissue and neoplasm assisted in determining interface boundaries. LESSONS: Intraoperative CEUS constitutes a useful adjunct for the intraoperative delineation of contrast-enhancing intramedullary tumors and in vivo confirmation of gross-total resection. Systematic investigation is needed to establish the role of CEUS for resection of intramedullary spinal tumors of various pathologies.

Primary meningeal melanoma masquerading as neurofibromatosis type 2: illustrative case.

BACKGROUND: Primary meningeal melanocytic neoplasms are exceedingly rare tumors, representing only 0.06% to 0.1% of all primary brain tumors and ranging in spectrum from benign localized tumors to highly aggressive malignant lesions. The diagnosis of these tumors is often challenging from clinical, radiological, and pathologic standpoints. Equally challenging is the distinction between primary meningeal melanocytic neoplasm and metastatic melanoma. OBSERVATIONS: The authors reported the case of a 41-year-old man with imaging findings diagnostic of neurofibromatosis type 2: bilateral internal auditory canal lesions (most consistent with bilateral vestibular schwannomas), two dura-based lesions presumed to be meningiomas, multiple spinal lesions consistent with peripheral nerve sheath tumors, and one intramedullary spinal lesion consistent with an ependymoma. Biopsy of these lesions revealed melanocytic neoplasms with mild to moderate atypia and a mildly elevated proliferation index, which made the distinction between benign and malignant challenging. In addition, the disseminated nature of these tumors made it difficult to determinate whether they arose from the meninges or represented metastases from an occult primary melanoma. LESSONS: This case illustrated the challenges presented by the diagnosis of meningeal melanocytic neoplasms and highlighted the importance of integrating the clinical and radiographic findings with histologic appearance and molecular studies.

Primary spinal melanoma: illustrative case.

BACKGROUND: Primary spinal melanoma is extremely rare, accounting for ∼1% of all primary melanomas. Typically presenting insidiously in the thoracic spinal cord, primary spinal melanomas can have an acute presentation due to their propensity to hemorrhage. OBSERVATIONS: Despite its rarity, primary spinal melanoma should be included in the differential diagnosis when a hemorrhagic pattern of T1 and T2 intensities is seen on magnetic resonance imaging. Furthermore, the complete diagnosis is crucial because the prognosis of a primary spinal melanoma is considerably more favorable than that of a primary cutaneous melanoma with metastatic spread. LESSONS: Resection is the treatment of choice, with some authors advocating for postoperative chemotherapy, immunotherapy, and/or radiation. We describe a case of acute quadriplegia from hemorrhagic primary spinal melanoma requiring resection.

Presentation, diagnosis, and treatment of a cerebellar tuberculoma: illustrative case.

BACKGROUND: Central nervous system (CNS) tuberculomas are a feared complication of tuberculosis (TB) infection. These lesions can present in varying manners and are associated with significant morbidity and mortality. Prompt diagnosis and treatment of the lesion and the underlying infection are critical in the care of these patients. The authors presented a case of a 45-year-old Yemeni immigrant presenting with a 3-month history of severe right temporo-occipital headaches with photophobia and night sweats. Imaging showed a rim-enhancing lesion in the right cerebellar hemisphere. OBSERVATIONS: Laboratory tests were unremarkable and within normal limits. QuantiFERON testing was negative, ruling out latent TB infection. The patient received a suboccipital craniotomy, and resection of the cerebellar lesion showed caseating granuloma formation, which was positive for acid-fast bacilli and Fite stain. LESSONS: CNS tuberculomas are an important differential to consider in patients with a history of primary TB, regardless of active disease or immunocompetent status. Resection of these lesions remains a viable treatment option that is safe and effective.

Three decades of progress from surgery to medical therapy for isolated neuroaxis BRAF V600E-positive Langerhans cell histiocytosis management: illustrative case.

BACKGROUND: "Langerhans cell histiocytosis" (LCH) is a term that encompasses single-system or multisystem disorders traditionally characterized by a proliferation of clonal CD1a+/CD207+ myeloid-derived histiocytes. In most cases of LCH, mitogen-activated protein kinase (MAPK) pathway somatic mutations lead to near universal upregulation of phosphorylated extracellular signal-regulated kinase expression. The clinical manifestations of LCH are numerous, but bone involvement is common. Intracranial lesions, especially as isolated manifestations, are rare. OBSERVATIONS: The authors presented the case of a long-term survivor of exclusive intracranial LCH that manifested with isolated craniofacial bone and intraparenchymal central nervous system recurrences, which were managed with 3 decades of multimodal therapy. The patient was initially diagnosed with LCH at age 2 years, and the authors documented the manifestations of disease and treatment for 36 years. Most of the patient's treatment course occurred before the discovery of BRAF V600E. Treatments initially consisted of chemotherapy, radiosurgery, and open resections for granulomatous LCH lesions. Into young adulthood, the patient had a minimal disease burden but still required additional radiosurgical procedures and open resections. LESSONS: Surgical treatments alleviated the patient's immediate symptoms and allowed for tumor burden control. However, surgical interventions did not cure the underlying, aggressive disease. In the current era, access to systemic MAPK inhibitor therapy for histiocytic lesions may offer improved outcomes.

Adamantinomatous craniopharyngioma associated with a compromised blood-brain barrier: patient series.

BACKGROUND: Adamantinomatous craniopharyngioma (ACP) is a highly morbid adult and pediatric brain tumor derived from epithelial remnants of the craniopharyngeal canal (Rathke's pouch), which gives rise to the anterior pituitary gland. Standard therapy includes maximal safe resection with or without radiation therapy. Systemic antitumor therapy remains elusive. Immune-related paracrine signaling involving the interleukin-6 receptor (IL-6R) may contribute to ACP pathogenesis. Tocilizumab, a recombinant humanized monoclonal antibody against IL-6R, is approved by the US Food and Drug Administration but does not cross an intact blood-brain barrier. OBSERVATIONS: In a phase 0 trial design, a single dose of tocilizumab was delivered intravenously before clinically indicated surgical intervention in 3 children with ACP. The presence of tocilizumab was assayed in plasma, tumor tissue, tumor cyst fluid, and cerebrospinal fluid (n = 1) using a novel enzyme-linked immunosorbent assay. Tocilizumab reached ACP tumor tissue and/or cyst fluid after one systemic dose in every patient. LESSONS: This finding helps explain extant data that indicate tocilizumab may contribute to ACP therapy. It further indicates that ACP does not reside behind an intact blood-brain barrier, dramatically broadening the range of potential antitumor therapies against this tumor. This has substantial implications for the design of future clinical trials for novel therapies against ACP in both children and adults.

Malignant intracerebral nerve sheath tumor in a patient with Noonan syndrome: illustrative case.

BACKGROUND: Malignant peripheral nerve sheath tumors (MPNSTs) within the neuroaxis are rare, usually arising from peripheral and cranial nerves. Even more scarce are cranial subclassifications of MPNSTs termed "malignant intracerebral nerve sheath tumors" (MINSTs). These tumors are aggressive, with a strong tendency for metastasis. With this presentation, alongside resistance to adjunctive therapy, complete excision is the mainstay of treatment, although it is often insufficient, resulting in a high rate of mortality. OBSERVATIONS: The authors report the case of an adult patient with a history of Noonan syndrome (NS) presenting with slowly progressive right-sided hemiparesis and right-sided focal motor seizures. Despite initial imaging and histology suggesting a left frontal lobe high-grade intrinsic tumor typical of a glioblastoma, subsequent molecular analysis confirmed a diagnosis of MINST. The patient's neurological condition improved after gross-total resection and adjuvant chemo-radiation; he remains on follow-up. LESSONS: MINSTs are rare neoplasms with a poor prognosis; management options are limited, with surgery being the cornerstone of treatment. Reports on rare tumors such as this will increase awareness of this particular pathology and disclose clinical experience. In this case, the authors were unable to establish a definite cause-and-effect relation between NS and MINST. Nevertheless, it remains the first reported case in the literature.

Pseudo-insular glioma syndrome: illustrative cases.

BACKGROUND: Lower-grade insular gliomas often appear as expansile and infiltrative masses on magnetic resonance imaging (MRI). However, there are nonneoplastic lesions of the insula, such as demyelinating disease and vasculopathies, that can mimic insular gliomas. OBSERVATIONS: The authors report two patients who presented with headaches and were found to have mass lesions concerning for lower-grade insular glioma based on MRI obtained at initial presentation. However, on the immediate preoperative MRI obtained a few weeks later, both patients had spontaneous and complete resolution of the insular lesions. LESSONS: Tumor mimics should always be in the differential diagnosis of brain masses, including those involving the insula. The immediate preoperative MRI (within 24-48 hours of surgery) must be compared carefully with the initial presentation MRI to assess interval change that suggests tumor mimics to avoid unnecessary surgical intervention.

Coccidioidal meningitis with multiple aneurysms presenting with pseudo-subarachnoid hemorrhage: illustrative case.

BACKGROUND: Coccidioidomycosis is a primarily self-limiting fungal disease endemic to the western United States and South America. However, severe disseminated infection can occur. The authors report a severe case of coccidioidal meningitis that appeared to be a subarachnoid hemorrhage (SAH) on initial inspection. OBSERVATIONS: A man in his early 40s was diagnosed with coccidioidal pneumonia after presenting with pulmonary symptoms. After meningeal spread characterized by declining mental status and hydrocephalus, coccidioidal meningitis was diagnosed. The uniquely difficult aspect of this case was the deceptive appearance of SAH due to the presence of multiple aneurysms and blood draining from the patient's external ventricular drain. LESSONS: Coccidioidal infection likely led to the formation of multiple intracranial aneurysms in this patient. Although few reports exist of coccidioidal meningitis progressing to aneurysm formation, patients should be closely monitored for this complication because outcomes are poor. The presence of basal cistern hyperdensities from a coccidioidal infection mimicking SAH makes interpreting imaging difficult. Surgical management of SAH can be considered safe and viable, especially when the index of suspicion is high, such as in the presence of multiple aneurysms. Even if it is unclear whether aneurysmal rupture has occurred, prompt treatment is advisable.

Isolated recurrence of acute myeloid leukemia in the cerebellum: illustrative case.

BACKGROUND: Myeloid sarcoma is a rare malignant hematopoietic neoplasm that arises at extramedullary sites. Although myeloid sarcoma may involve any organ, central nervous system (CNS) involvement is exceptionally rare. To date, few case reports and case series have described CNS myeloid sarcoma, the majority of which include peripheral disease. OBSERVATIONS: The authors present an illustrative case of an adult male with acute myeloid leukemia (AML) in remission relapsing with an isolated, diffuse myeloid sarcoma of the cerebellum. Magnetic resonance imaging showed posterior fossa crowding and diffuse enhancement within the cerebellar white matter without an apparent mass lesion. The patient required ventriculostomy due to obstructive hydrocephalus and ultimately suboccipital craniectomy with duraplasty due to posterior fossa compression. An open cerebellar biopsy revealed myeloid sarcoma. Peripheral studies did not meet the criteria for recurrent AML. The patient subsequently received high-dose systemic chemotherapy and has responded well to treatment. LESSONS: Myeloid sarcoma may be a neurosurgical lesion because it has the potential to cause mass effect with obstructive hydrocephalus requiring emergent cerebrospinal fluid diversion and possible decompression. The authors report a rare case of isolated recurrence of AML in the form of diffuse CNS myeloid sarcoma and describe the role of neurosurgery in its diagnosis and treatment.

Rosai-Dorfman-Destombes disease: isolated intracranial without nodal involvement presentation. Illustrative case.

BACKGROUND: Rosai-Dorfman-Destombes disease is a rare and heterogeneous entity that has been associated with autoimmune, hereditary, and malignant diseases. There is controversy about its etiopathogenesis, clinical course, and therapeutic management. OBSERVATIONS: The authors report a case of a 61-year-old man with a history of progressive headache without any other symptoms. Magnetic resonance imaging of the brain revealed multiple irregular lesions with an initial diagnostic impression of meningiomatosis. An excisional biopsy was performed, and the pathology report stated the finding was Rosai-Dorfman-Destombes disease. LESSONS: The uniqueness of this case is its rarity. The isolated intracranial location presents many diagnostic and therapeutic challenges, with radiological and clinical characteristics similar to those of other central nervous system tumors. There is currently no clear evidence of the pathogenesis and therapeutic management of this condition. Follow-up of these patients will help elucidate the natural history of this condition and the benefits of various treatment modalities.

Endoscopic endonasal surgery for massive subarachnoid neurocysticercosis: illustrative case.

BACKGROUND: Subarachnoid neurocysticercosis (NCC) is associated with high morbidity and mortality rates. Conventional transcranial approaches and transventricular endoscopy have been previously reported for extraparenchymal NCC and ventricular NCC, respectively. By October 2019, endonasal endoscopic approaches had not been used for the treatment of NCC. OBSERVATIONS: A 54-year-old-woman with NCC was admitted with acute neurological deterioration due to severe intracranial hypertension caused by massive subarachnoid NCC cysts, as evidenced on magnetic resonance imaging (MRI) with great brainstem compression. The case was discussed, and an endoscopic endonasal resection of the NCC cysts was scheduled. The diagnosis was confirmed by pathological anatomy. There were no complications in the surgery, with marked neurological improvement. Control MRIs demonstrated a significant reduction of NCC cysts. LESSONS: Minimally invasive approaches are an excellent alternative for skull-base tumoral and infectious pathology. Prior knowledge of the pathophysiology and the authors' experience in the management of patients with NCC allowed them to propose this approach, with optimal results.