Laser Interstitial Thermal Therapy to the Posterior Fossa: Challenges and Nuances.

BACKGROUND: Posterior fossa tumors are rare in adults and pose a challenge to treat due to the bony contour of the posterior fossa, complex anatomical structures including deep venous sinuses, and the proximity of the fourth ventricle and brain stem. We describe our experience with laser interstitial thermal therapy (LITT) for the management of brain metastases and radiation necrosis of the posterior fossa. METHODS: We retrospectively analyzed 13 patients with metastases and radiation necrosis of the posterior fossa managed with LITT. RESULTS: Thirteen patients with histopathologically confirmed radiation necrosis (n = 5) and metastases (n = 8) of the posterior fossa underwent LITT. The median preoperative tumor was 4.66 cm3, and median postoperative ablation cavity volume was 6.29 cm3. The median volume of the ablation cavity was decreased to 2.90 cm3 at a 9-month follow-up. The median volume of peritumoral edema was 12.25 cm3, which fell to a median of 5.77 cm3 at 1-month follow-up. The median progression-free survival was 7 months (range, 3-14 months) and the mean overall survival was 40 months (range, 2-49 months) after LITT. There were no intraoperative complications. One patient experienced palsy of the seventh and eighth cranial nerves on follow-up, attributable to LITT. CONCLUSIONS: Lesions of the posterior fossa are challenging to treat given their proximity to the dura and venous sinuses. Our findings demonstrate that LITT ablation may be a safe and feasible option for metastases and radiation necrosis of the posterior fossa. Larger studies are needed to confirm the efficacy of this approach.

Brain Metastasis of Pheochromocytoma: Diagnostic and Therapeutic Challenge.

BACKGROUND: Pheochromocytoma brain metastasis is extremely rare. Few cases have been reported in the literature. Therefore, diagnosis and effective treatment of these lesions are difficult. CASE DESCRIPTION: Here, we report the case of 29-year-old woman, who was operated on for a right adrenal pheochromocytoma. Fourteen months later, a posterior fossa tumor was diagnosed. Radiologic findings mimicked an extra-axial lesion. The radiologic differential diagnosis was difficult even using magnetic resonance imaging spectroscopy. The patient was operated on through a retrosigmoid approach. Local recurrence occurred 6 months after first surgery. The patient died 1 month later, despite a second operation. CONCLUSIONS: Although the occurrence of brain metastases in pheochromocytoma is not prevalent, patients presenting with suggestive features need to be carefully considered. Magnetic resonance imaging can help in differential diagnosis with a primary brain tumor. There are no established guidelines for the treatment of pheochromocytoma brain metastasis, for which the prognosis remains dismal, despite effective surgery.

Diffuse spinal spreading following previous intracranial intradural chordoma resection: A rare case report.

INTRODUCTION: Chordoma is a malignant tumor that usually involves the axial skeleton. Intradural chordomas are even rarer and 37 cases have been reported to the best of our knowledge. We present a case of a patient with an atypical metastatic diffuse intradural spinal involvement. CASE DESCRIPTION: We present a 33-year-old woman previously submitted to five brain surgeries to treat a posterior fossa intradural chordoma since December 2012. Currently, she presented almost with right and left hemiplegia (grade 2 bilaterally) and also left oculomotor, adbucent and facial nerve paresis. We performed neuroaxis magnetic resonance MR which disclosed stability of posterior fossa tumor which was previously irradiated. However, there were new intradural lesions at the level of C3, T11/T12 and L4/L5/S1 vertebrae. DISCUSSION: With the advent of contemponaeous surgery, radiotherapy options and even available chemotherapy to treat Chordomas (Imatinib), patients may experience enlarged survival and thus face complications such as drop metastases along neuroaxis. Our case illustrates a late (6 years) follow-up presentation of an initial posterior fossa intradural chordoma. It suggests that whole neuraxis involvement may be the final presentation of all patients harbouring chordomas and surviving after adequate initial treatment.

Posterior fossa recurrence of WHO grade II and III supratentorial gliomas.

OBJECTIVE/BACKGROUND: Posterior fossa (PF) recurrences of supratentorial (ST) World Health Organization (WHO) grade II and III gliomas are thought to be rare and to have grim prognoses. METHODS: This study entailed searching through our database and reviewing the records of patients with grade II and III ST gliomas who developed PF recurrence with no overt secondary gliomatosis or leptomeningeal spread. RESULTS: Of 2266 grade II and III gliomas, 14 fulfilled the inclusion criteria: 5 oligodendrogliomas (O; 1 OII, 4 OIII); 7 astrocytomas (A; 4 AII, 3 AIII); and 2 oligoastrocytomas (OA; both OAIII). The male/female gender ratio was 10/4, and median age at recurrence was 43 years. Two groups were identified. In one group (n=8; 1 AII, 3 AIII, 2 OAIII, 2 OIII), a rapidly growing contrast-enhancing PF mass (6/8) was associated with ST progression, and median survival time after detection was only 6.5 months despite radiotherapy and/or chemotherapy. In the second group (n=6; 3 AII, 1 OII, and 2 OIII), a non-contrast-enhancing (5/6), asymptomatic (5/6), slow-growing PF mass remained isolated, and treatment with radio- or chemotherapy produced objective responses in three patients and durable stabilization in the remaining three. After a median follow-up of 63months, only one patient died due to delayed recurrence of the ST lesion, while the remaining five patients are still alive. CONCLUSION: Non-contiguous PF relapses of ST grade II and III gliomas are rare. A high-grade ST tumor that is concomitantly progressing appears to be a predictor of poor survival. Conversely, the tumor course may be indolent if the ST lesion is low-grade and non-progressive at the time of PF involvement. The possible mechanism(s) behind this tropism are also discussed.

Posterior Fossa Metastasis-Associated Obstructive Hydrocephalus in Adult Patients: Literature Review and Practical Considerations from the Neuro-Oncology Club of the French Society of Neurosurgery.

BACKGROUND: There is no consensus concerning the management of adult patients with posterior fossa metastasis-associated obstructive hydrocephalus, especially regarding surgical procedures. A literature review was performed to assess the surgical strategy in the management of patients with metastatic brain tumor. METHODS: A literature search was conducted of PubMed in November 2017 to identify all studies concerning brain metastases and obstructive hydrocephalus in English. All studies (except case reports and pediatric studies) between December 1953 and November 2017 that were about posterior fossa metastasis-associated obstructive hydrocephalus in adult patients were eligible. Eligible studies were classified by level of evidence. We assessed epidemiology, clinical and imaging findings, neurosurgical management, and prognosis of adult patients with posterior fossa metastasis-associated obstructive hydrocephalus. We suggest some practical considerations and a management decision tree on behalf of the Neuro-oncology Club of the French Society of Neurosurgery, with evidence-based analysis. RESULTS: Direct surgical resection could be considered for patients with asymptomatic obstructive hydrocephalus, and endoscopic third ventriculostomy seems to be a reasonable procedure for patients with symptomatic obstructive hydrocephalus. A ventriculoperitoneal or atrial shunt seems to be a valid alternative when patients have a history of central nervous system infection or ventricular hemorrhage, leptomeningeal carcinomatosis, or unfavorable anatomy for an endoscopic third ventriculostomy to be performed. CONCLUSIONS: The Neuro-oncology Club of the French Society of Neurosurgery suggests a prospective assessment of these neurosurgical procedures to compare their safety and efficacy.

PHOX2B is a reliable immunomarker in distinguishing peripheral neuroblastic tumours from CNS embryonal tumours.

AIMS: The PHOX2B gene regulates neuronal maturation in the brain stem nuclei associated with cardiorespiratory function and in the autonomic sympathetic and enteric nervous system. PHOX2B expression is a reliable immunomarker for peripheral neuroblastic tumours; however, no systematic evaluation of central nervous system (CNS) embryonal tumours was included in the studies. We encountered two cases in which the differential diagnosis included neuroblastoma and CNS embryonal tumour, and we hypothesised that PHOX2B immunostain would be helpful in establishing the diagnosis. METHODS AND RESULTS: PHOX2B immunostain was performed on 29 paediatric cases, with adequate controls: one retroperitoneal embryonal tumour in a child with retinoblastoma (index 1), one posterior fossa embryonal tumour in a child with a neuroblastoma (index 2), seven medulloblastomas, four atypical teratoid/rhabdoid tumours (ATRT), four retinoblastomas, six pineoblastomas, four embryonal tumours with multilayered rosettes (ETMR) and two CNS embryonal tumours, not elsewhere classified. Cell lineage immunomarkers (GFAP, OLIG2, synaptophysin, NeuN, CRX, PGP 9.5), immunosurrogates for molecular alterations (beta-catenin, INI1, Lin-28), array CGH and OncoPanel were performed as needed. Medulloblastomas, ATRTs, ETMRs, retinoblastomas and CNS embryonal tumours not elsewhere classified were essentially negative for PHOX2B. Two of six pineoblastomas had significant PHOX2B expression, while the rest were negative. Index 1 was negative for PHOX2B and PGP 9.5 and positive for CRX, consistent with retinoblastoma. Index 2 had diffuse PHOX2B expression, MYCN amplification and no copy number changes of medulloblastoma, in keeping with neuroblastoma. CONCLUSION: PHOX2B antibody is helpful in distinguishing between peripheral neuroblastic and CNS embryonal tumours, which are immunonegative, with the caveat that a subset of pineoblastomas has significant expression.

Surgical management of posterior fossa metastases.

The diagnosis of brain metastases is associated with a poor prognosis reflecting uncontrolled primary disease that has spread to the relative sanctuary of the central nervous system. 20 % of brain metastases occur in the posterior fossa and are associated with significant morbidity. The risk of acute hydrocephalus and potential for sudden death means these metastases are often dealt with as emergency cases. This approach means a full pre-operative assessment and staging of underlying disease may be neglected and a proportion of patients undergo comparatively high risk surgery with little or no survival benefit. This study aimed to assess outcomes in patients to identify factors that may assist in case selection. We report a retrospective case series of 92 consecutive patients operated for posterior fossa metastases between 2007 and 2012. Routine demographic data was collected plus data on performance status, primary cancer site, details of surgery, adjuvant treatment and survival. The only independent positive prognostic factors identified on multivariate analysis were good performance status (if Karnofsky performance score >70, hazard ratio (HR) for death 0.36, 95 % confidence interval (CI) 0.18-0.69), adjuvant whole brain radiotherapy (HR 0.37, 95 % CI 0.21-0.65) and adjuvant chemotherapy where there was extracranial disease and non-synchronous presentation (HR 0.51, 95 % CI 0.31-0.82). Patients presenting with posterior fossa metastases may not be investigated as thoroughly as those with supratentorial tumours. Staging and assessment is essential however, and in the meantime emergencies related to tumour mass effect should be managed with steroids and cerebrospinal fluid diversion as required.

Significance of Primary Tumor Location and Histology for Brain Metastasis Development and Peritumoral Brain Edema in Lung Cancer.

BACKGROUND: Brain metastasis of lung cancer adversely affects overall survival (OS) and quality of life, while peritumoral brain edema is responsible for life-threatening complications. METHODS: We retrospectively analyzed the clinicopathological and cerebral radiological data of 575 consecutive lung cancer patients with brain metastases. RESULTS: In adenocarcinoma and squamous cell carcinoma, peritumoral brain edema was more pronounced than in small-cell lung cancer (p < 0.001 and p < 0.001, respectively). There was a positive correlation between the size of metastasis and the thickness of peritumoral brain edema (p < 0.001). It was thicker in supratentorial tumors (p = 0.019), in younger patients (≤50 years) (p = 0.042), and in females (p = 0.016). The time to development of brain metastasis was shorter in central than in peripheral lung cancer (5.3 vs. 9.0 months, p = 0.035). Early brain metastasis was characteristic for adenocarcinomas. A total of 135 patients had brain only metastases (N0 disease) characterized by peripheral lung cancer predominance (p < 0.001) and a longer time to development of brain metastasis (9.2 vs. 4.4 months, p < 0.001). OS was longer in the brain only subgroup than in patients with N1-3 diseases (p < 0.001). CONCLUSIONS: The clinicopathological characteristics of lung cancer are related to the development and radiographic features of brain metastases. Our results might be helpful in selecting patients who might benefit from prophylactic cranial irradiation.

Metastatic Thymic Carcinoma Presenting as a Posterior Fossa Mass: Case Report and Review of the Literature.

BACKGROUND: Thymic epithelial tumors (TETs) are uncommon lesions, and cerebral metastases from these tumors are even rarer. We report a case of a posterior fossa metastasis in a patient with a known history of thymic carcinoma. CASE DESCRIPTION: A 47-year-old man with a history of Hodgkin lymphoma and thymic carcinoma presented with headache, nausea, and ataxia. Imaging revealed a large posterior fossa mass. This lesion was completely resected without complications. Pathologic examination was consistent with metastatic thymic carcinoma. The patient's symptoms were relieved postoperatively. We reviewed the literature and identified an additional 44 cases of TETs with metastases to the brain. Although brain metastases are generally associated with a poor prognosis in patients with TETs, survival of more than 1 year may be accomplished with surgical resection and multimodality treatment. CONCLUSIONS: Metastasis should be considered in the differential of a patient with a TET and an intracranial mass lesion.

Primary Cerebellar Gliosarcoma with Extracranial Metastases: An Orphan Differential Diagnosis.

BACKGROUND: Gliosarcomas are rare, malignant primary brain tumors, most commonly located in the temporal lobe, that contain both glial and mesenchymal elements. Gliosarcomas located within the cerebellum are exceedingly rare. The previously unreported finding of a cerebellar gliosarcoma concurrently with an extracranial metastasis to the lungs is discussed here. CASE DESCRIPTION: A 57-year-old man presented with a 3-month history of chest pain, weight loss, headaches, and vomiting. Physical examination revealed a left cerebellar dysfunction, and the radiological work-up revealed a 6 × 6-cm right apical pulmonary tumor and a 4 × 3.5 × 3.8-cm peripherally enhancing left cerebellar mass. On the basis of a smoking history in the setting of a lung lesion and cerebellar mass, the presumptive diagnosis was primary lung cancer with metastasis to the cerebellum. Gross total resection of a firm pseudo-encapsulated cerebellar mass was performed. The microscopic features and the immunohistochemical profile confirmed the diagnosis of Gliosarcoma. The thoracic lesion was removed subsequently, and pathology confirmed it as an extracranial metastasis from the cerebellar gliosarcoma. Adjuvant radiation and chemotherapy were then administered. No clinical or radiographic evidence of recurrence was observed during one year of follow-up monitoring. CONCLUSIONS: To the best of our knowledge, a primary infratentorial gliosarcoma with extracranial metastases has not been previously described.

Renal cell carcinoma metastasis to the cerebellopontine cistern: intraoperative Onyx embolization via direct needle puncture.

We report a rare case of a renal cell carcinoma (RCC) metastasis occupying the cerebellopontine and cerebellomedullary cisterns, and describe an alternative strategy for embolizing hypervascular intracranial tumors. A middle aged patient with a distant history of RCC presented with headaches, nausea, and vomiting, and was found to have an enhancing mass in the left cerebellopontine and cerebellopontine cisterns. The initial surgical resection was aborted due to excessive bleeding. After an unsuccessful attempt at intra-arterial embolization, the patient returned to the operating room and the tumor was devascularized by direct needle puncture Onyx embolization under biplane fluoroscopy. The devascularized tumor was then successfully dissected from the brainstem and adherent lower cranial nerves. In properly selected cases, open surgical direct needle puncture embolization of intracranial vascular tumors under biplane fluoroscopy is a viable alternative devascularization method.

Metastasis of soft-tissue myoepithelial carcinoma to clivus.

The differential diagnosis for masses involving the clivus is broad. The authors present a case of myoepithelial carcinoma metastatic to the clivus, a lesion that has not been reported to their knowledge. This 14-year-old girl with a history of myoepithelial carcinoma originating in the soft tissues of the left hip and metastatic to the lung presented with left lateral gaze palsy. Imaging demonstrated a 3 × 3-cm osteolytic mass in the clivus. Microscopic transsphenoidal resection with endoscopic assistance was performed. Pathological findings were consistent with the previously diagnosed myoepithelial carcinoma. Within 4 weeks postoperatively and 2 weeks into a chemotherapeutic regimen, the tumor exhibited progression. Radiation therapy was started and growth of the tumor was halted. Myoepithelial carcinoma should be included in the differential diagnosis for clival masses, especially in patients with previously diagnosed myoepithelial carcinoma. The primary management of this tumor should be with chemotherapy and radiation, with surgery serving only for decompression.

Man with posterior fossa tumors 15 years apart.

A 48-year-old man with a history of hypertension, peripheral vascular disease and a 50-pack-year history of smoking presented with new onset vertigo, tinnitus, diplopia and ataxia in January 1978. CT scan showed a radiolucent defect in the left cerebellar hemisphere with a possible mural nodule. In ensuing months, he experienced worsening symptoms with a corresponding increase in lesion size on re-imaging. Months later, a left posterior fossa craniotomy was performed and revealed a single cystic lesion containing copious amounts of straw-colored fluid and a single mural nodule in the inferior portion of the cyst. Following resection, he was followed clinically until 1985 at which time follow-up was discontinued. He did well until January 1993 when he presented with progressively worsening episodic headaches and retro-orbital pressure. Subsequent MRIs of the brain and spine (February 1993, March 1993) showed multiple lesions along the neuraxis involving the superficial brain parenchyma, leptomeninges, and dura. Despite therapy, his condition progressively declined until he succumbed. A brain-only autopsy revealed numerous small tumor nodules involving the base of the brain over both frontal and temporal lobes, midbrain, pons, right optic nerve, pituitary fossa, and the base of the skull. Pathologic evaluation revealed metastatic hemangioblastoma. Metastatic hemangioblastoma is a rare entity, with only a few reported cases in the literature to date.

Metastatic brain tumors: a retrospective review in East Azarbyjan (Tabriz).

A set of one hundred and twenty nine patients with known primary malignancy and suspected brain metastasis was reviewed in present study. The patients were selected among patients presented to the MRI section of Imam Khomeini Hospital or a private MRI center in Tabriz (Iran). Primary tumor site, clinical manifestations, number and site of lesions were identified in this patient population. The primary tumor site was breast in 55 patients (42.6%), followed by lung (40.3%), kidney (7.7%), colorectal (4.6%), lymphoma (3.1%) and melanoma (1.5%). Most patients were presented with features of increased intracranial pressure (headaches and vomiting), seizures and focal neurologic signs. Single brain metastasis occurred in 16.3% of patients, while multiple lesions accounted for 83.7% of patients. Ninety seven patients had supratentorial metastases (75.2%). Twenty cases (15.5%) had metastases in both compartments. Infratentorial lesions were observed only in twelve patients (9.3%).

Infratentorial brain metastases of pediatric non-epithelial malignant tumors: three case reports.

Three pediatric patients with infratentorial metastatic non-epithelial malignant brain tumors were successfully treated by radical surgical resection followed by aggressive radiochemotherapy. One patient with neuroblastoma and two with rhabdomyosarcoma were successfully treated by first line multimodal treatments, but developed infratentorial metastasis after several months of remission. All patients revealed intracranial metastases manifesting as rapidly progressing neurological symptoms caused by mass effect in the posterior fossa. Radical surgical resection was performed without morbidity. The patients were then treated by adjuvant radiochemotherapy with or without autologous peripheral blood stem cell transplantation, resulting in complete remission. Two patients developed extracranial recurrences 4 months after the treatments for intracranial metastases. One patient was treated by second high-dose chemotherapy with allogeneic cord blood transplantation, again resulting in complete remission. Another patient was treated by second chemotherapy and maintaining stable disease. The other patient maintained complete remission. All three patients were alive without neurological deficit for 8, 11, and 12 months after diagnosis of brain metastasis. Patients with infratentorial brain metastases of highly malignant pediatric non-epithelial tumors are in a severe clinical state, but still can have longer and useful lives with aggressive multimodal treatments combined with radical surgical resection.

Brain metastases in patients with pelvic or abdominal malignancy do not prevail in the posterior fossa: a retrospective study.

Pelvic and gastrointestinal tumors are generally considered to have a predilection to metastasize to the posterior fossa rather than to the supratentorial brain. Review of imaging of 100 patients with brain metastases from pelvic and gastrointestinal primary tumors and of 100 patients with brain metastases from other primary tumors did not reveal a difference in distribution of brain metastases between the two groups of patients. So, there is no evidence that pelvic and gastrointestinal tumors metastasize preferentially to the posterior fossa.