Cerebellar pilocytic astrocytoma with leptomeningeal dissemination: case report

Intramedullary spinal cord tumors in pediatric patients presenting later with brain lesions: case series and systematic review of the literature

PURPOSE

Intramedullary spinal cord tumors are an uncommon pathology in adults and children. Most descriptive studies of intramedullary spinal cord tumors have not focused on a possible association with future brain lesions. To the best of our knowledge, few reports describe this potential relationship. This is one of the most extensive case series of secondary brain lesions of intramedullary spinal cord tumors in the pediatric population.

METHODS

Retrospective chart review was performed on pediatric patients (21 years old and younger) who underwent resection of an intramedullary spinal cord tumor at two tertiary care hospitals from 2001 to 2020. Patients previously treated or diagnosed with spinal cord tumor, and subsequent development of intracranial manifestation of the same or different tumor, were included. Data regarding epidemiology, surgical intervention, and clinical and follow-up course were gathered. Data analysis was performed according to a standardized clinical protocol with a literature review.

RESULT

More than 500 patients underwent intradural spinal tumor resection surgeries at participating hospitals from 2001 to 2020. After excluding adult patients (older than 21 years old) and those with extramedullary lesions, 103 pediatric patients were identified who underwent resection of an intramedullary spinal cord tumor. Four underwent resection of an intermedullary tumor and later in their follow-up course developed a secondary intracranial neoplasm. In every case, the secondary neoplasm had the same pathology as the intramedullary tumor. Three of the patients had tumors at the cervico-thoracic junction, and one patient had a high cervical tumor. These patients had a negative primary workup for any metastatic disease at the time of the presentation or diagnosis. Complete and near complete resection was performed in three patients and subtotal in one patient.

CONCLUSION

Secondary brain tumors disseminated after initial spinal cord tumor are extremely rare. This study aims to allow specialists to better understand these pathologies and treat these rare tumors with more certainty and better expectations of unusual associated lesions and conditions.

Multifocal Infratentorial Pilocytic Astrocytoma in an Adult Patient

BACKGROUND

Pilocytic astrocytoma is a benign glial tumor typically presenting in children. It is rare for adults to present with pilocytic astrocytoma and even less likely to manifest with multiple foci of lesions especially in nonoptic or hypothalamic locations.

CASE DESCRIPTION

Our patient was a 37-year old man presenting with varied cranial neuropathies, cerebellar dysfunction, and long tract signs, with imaging demonstrating 3 discrete ill-defined contrast-enhancing lesions affecting the cerebellar peduncles, brainstem, and cervicomedullary junction. Neuronavigation-guided biopsy confirmed World Health Organization grade 1 pilocytic astrocytoma; the patient was treated with radiotherapy.

CONCLUSIONS

To our knowledge, we believe this is the first reported case with multifocal infratentorial pilocytic astrocytoma on presentation in an adult patient in the absence of a prior history of associated risk factors such as neurofibromatosis 1 or chemoradiotherapeutic intervention.

Metastatic Low-Grade Gliomas in Children: 20 Years' Experience at St. Jude Children's Research Hospital

BACKGROUND

Patients with low-grade gliomas (LGG), which are the most common childhood brain tumors, have excellent long-term survival. Dissemination of LGG is rare. Robust data on the incidence, presentation, patterns of dissemination, disease behavior, outcome, and best-management approaches do not exist. We describe 20 years of follow-up of children with metastatic LGG.

PROCEDURE

Data collected during the period 1990-2010 were retrospectively reviewed for the following inclusion criteria: diagnosis of metastatic LGG, age younger than 21 years at initial diagnosis, and magnetic resonance imaging of the brain and/or spine at diagnosis and/or follow-up. Patient demographics, pathology, treatment modalities, and outcome were reviewed.

RESULTS

Of 599 patients with LGG, 38 (6%) had metastatic disease at either diagnosis or follow-up. Most tumors (87%) were located in the brain, and half of the patients had metastatic disease at presentation. The most common diagnosis was pilocytic astrocytoma (55%). Chemotherapy was the most common initial treatment modality. Median survival of the group was 6.2 years (range, 0.1-16.9 years). Fifteen (40%) patients died at a median of 6 years from diagnosis (range, 0.8-15 years). Overall survival at 5, 10, and 15 years was 80.7 ± 6.6%, 63.0 ± 10.2%, and 50.9 ± 16.0%, respectively.

CONCLUSION

This study describes the longest follow-up of children with metastatic LGG. LGG is underestimated and entails major morbidity and mortality. Prospective studies are needed to learn the true incidence, study the biology, and determine the best approaches to diagnosis, treatment, and follow-up.

Pilocytic astrocytoma with leptomeningeal dissemination

PURPOSE

Pilocytic astrocytoma (PA) is a common pediatric glioma that is generally characterized by indolent growth. However, there are reports of PA disseminating throughout the central nervous system. Given the rarity of dissemination, the appropriate treatment for these patients is poorly defined. In this case series, we describe the clinical characteristics and treatment outcomes of six children treated for disseminated PA at our institution and review the current published literature.

METHODS

Six cases of disseminated PA treated at the University of Texas MD Anderson Cancer Center were identified. Demographics, disease characteristics, and follow-up data were compiled. Fifty-three reported cases were identified in the published literature.

RESULTS

Our cohort's mean age at presentation was 7 years, and the mean time to identification of disseminated disease was 12 months after initial diagnosis. Two patients underwent chemotherapy, and all underwent proton beam radiation therapy to all or part of the craniospinal axis. With a median follow-up of 24 months after radiation therapy, five of six patients were alive, four with stable disease and one with progressive disease.

CONCLUSIONS

Treatment of disseminated PA is frequently multi-modal, including surgical resection, chemotherapy, and radiation therapy. On the basis of early clinical data, extended-field radiation therapy is a viable option for treating disseminated PA.

Radiographically distinct variant of pilocytic astrocytoma: a case series

The imaging findings of pilocytic astrocytomas are classically described as a cyst with an enhancing mural nodule. We report 2 unusual cases of multicystic cerebellar midline masses that were proven to be pilocytic astrocytomas. The uniqueness of the imaging features in these cases may represent an important variant of pilocytic astrocytomas. Recognition of this variant may prevent an unnecessary workup to exclude other etiologies such as parasitic infection (ie, cysticercosis) or cystic metastatic disease.

Use of T2 signal intensity of cerebellar neoplasms in pediatric patients to guide preoperative staging of the neuraxis

OBJECT

The question of whether to obtain routine or selective preoperative imaging of the neuraxis in pediatric patients with cerebellar neoplasms remains a controversial topic. Staging of the neuraxis is generally considered beneficial in patients with neoplasms associated with an elevated risk of leptomeningeal dissemination (LD). When these studies are obtained preoperatively, there is a decrease in the number of false-positive images related to debris in the immediate postoperative period. Additionally, knowledge of the extent of spread has the potential to affect the risk/benefit analysis of aggressive resection. Although the majority of pediatric neurosurgeons surveyed choose to obtain selective preoperative imaging of the neuraxis in cases of cerebellar neoplasms "with findings suggestive of high-grade pathology," an evidence-based protocol in the literature is lacking. The goal of this study was to assess radiological characteristics of tumors with an elevated risk of LD and identify a method to help guide preoperative imaging of the neuraxis.

METHODS

The authors first reviewed the literature to gain an appreciation of the risk of LD of pediatric cerebellar neoplasms based on underlying histopathology and/or grade. Available evidence indicates preoperative imaging of the neuraxis in patients with Grade I tumors to be of questionable utility. In contrast, evidence suggested that preoperative imaging of the neuraxis in patients with Grades II-IV neoplasms was clinically warranted. The authors then evaluated an extensive base of neuroradiological literature to identify possible MR imaging and/or CT findings with the potential to differentiate Grade I from higher-grade neoplasms in pediatric patients. They analyzed the preoperative radiological findings in 50 pediatric patients who had undergone craniotomy for resection of cerebellar neoplasms at Vanderbilt Children's Hospital since 2003 with reference to 7 chosen radiological criteria. Logistic regression models were fit using radiological features to determine the best predictors of Grades II-IV tumors. Receiver operating characteristic methods were used to identify diagnostic properties of the best predictors.

RESULTS

The relative T2 signal intensity (RT2SI), an indirect measure of the water content of the solid component of the tumor, was best able to identify neoplasms with an elevated risk of LD. An RT2SI value of 0.71 was selected by the authors as the best operating point on the curve. Of the 31 neoplasms retrospectively designated as hypointense T2-weighted lesions (RT2SI ≤ 0.71), 30 (97%) were Grade II or higher. All medulloblastomas, ependymomas, and high-grade (Grades III and IV) neoplasms were hypointense T2-weighted lesions. Of the 19 T2-weighted hyperintense neoplasms (RT2SI > 0.71), 16 (84%) were Grade I and 3 were Grade II.

CONCLUSIONS

Measurement of the RT2SI can help predict Grade II-IV tumors at an elevated risk of leptomeningeal spread and guide staging of the neuraxis. Pediatric patients with cerebellar neoplasms found to have an RT2SI of less than or equal to 0.71 are recommended for neuraxis imaging prior to surgery.

Dissemination patterns of pilocytic astrocytoma

Two patients with multifocal pilocytic astrocytoma diagnosed by magnetic resonance imaging (MRI) and confirmed by histopathological examination are reported. They presented distinct sites and mechanisms of metastasis: to distant ventricles through the cerebral spinal fluid (CSF) in patient 1 and to contralateral parenchyma, possibly through white matter tracts, in patient 2, a pathway not so far reported in pilocytic astrocytoma. Early detection of multifocal pilocytic astrocytoma by MRI may change treatment strategies and improve prognosis.

Spinal seeding of a pilocytic astrocytoma following multiple subtotal resections

We report the case of a 4-year-old girl presenting with spinal and leptomeningeal dissemination following several subtotal resections of cerebellar pilocytic astrocytomas.

Management of pilocytic astrocytoma with diffuse leptomeningeal spread: two cases and review of the literature

INTRODUCTION

Leptomeningeal dissemination of juvenile pilocytic astrocytoma (JPA) is a rare event. We report two children with disseminated JPAs treated with a chemotherapeutic agent, temozolomide, after progression of the disease despite surgery, traditional chemotherapy, and/or radiation therapy.

CASE REPORTS

Patient 1 presented with hydrocephalus and progressive lower extremity weakness, and was found to have a suprasellar mass as well as extensive spinal disease. Ventriculoperitoneal shunting, decompressive laminectomy with spinal tumor debulking, and chemotherapy with carboplatin and vincristine were initially employed. However, disease progressed and craniospinal irradiation and temozolomide were used. Patient 1 remains in a fair condition today, 2 years later. Patient 2 presented at 8 months of age with failure to thrive. Imaging revealed a cystic lesion in the hypothalamic region with extensive subarachnoid metastatic disease to the spine. Biopsy was performed followed by chemotherapy with vincristine, cyclohexylchloroethylnitrosourea (CCNU), 6-TG, and procarbazine. Due to the continued progression of the disease, cytoreductive surgery was performed and her chemotherapeutic regimen was switched to temozolomide. Two years after initial presentation patient 2 is clinically much improved with stable residual disease.

DISCUSSION

We review the literature and discuss treatment strategies for this challenging disease.

Leptomeningeal metastasis of primary central nervous system (CNS) neoplasms

Leptomeningeal dissemination of primary CNS tumors varies widely by histologic subtype. In certain tumors including medulloblastoma, ependymoma, germ cell tumors, and primary CNS lymphoma, seeding of the cerebrospinal fluid space is a critical factor in determining stage, prognosis and appropriate therapy. Other tumor types, such as glioma, may have radiographic evidence of leptomeningeal metastases without clear impact on prognosis or therapy.

Leptomeningeal dissemination of pilocytic astrocytoma at diagnosis in childhood: two cases report

Pilocytic astrocytoma (PA) is a benign tumor that rarely spread along the neuraxis. At the moment there are no more than five cases of leptomeningeal dissemination (LD) from PA at diagnosis described in the literature. Different patterns of presentation or recurrence may be noted: local recurrence, malignant transformation, multicentric disease or metastatic disease. LD and multicentric disease can be distinct pathological entities. We report two cases and analyse literature, emphasizing leptomeningeal spread at presentation. Hydrocephalus, biopsy and parcial ressection are likely to be favorable factors to the occurrence of LD. Otherwise, LD may be part of natural history of PA, as evidenced by its ocurrence in non-treated cases.

Leptomeningeal metastases

LM is an increasingly common neurologic complication of cancer with variable clinical manifestations. Although there are no curative treatments, currently available therapies can preserve neurologic function and potentially improve quality of life. Further research into the mechanisms of leptomeningeal metastasis will elucidate molecular and cellular pathways that may allow identification of potential targets to interrupt this process early or to prevent this complication. Animal models are needed to further define the pathophysiology of LM and to provide an experimental system to test novel treatments [242-245]. There is an urgent need to develop new drug-based or radiation-based treatments for patients with LM. Randomized clinical trials are the appropriate study design to determine the efficacy of new treatments for LM. However, surrogate markers for response must be developed to facilitate the identification of effective regimens. Survival is not the optimal end point for such studies as most patients who develop this complication already have advanced, incurable cancer. Prevention of or delay in neurologic progression is one objective that has been utilized in recent randomized trials in patients with LM, and this end point deserves further attention. Although the development of LM represents a poor prognostic marker in patients with cancer it is important for physicians to recognize the symptoms and signs of the disease and establish the diagnosis as early in the disease course as possible. This may provide an opportunity for effective intervention that can improve quality of life, prevent further neurologic deterioration and, for a subset of patients, improve survival.

Long-term outcome after resection of benign cerebellar astrocytomas in children and young adults (0-19 years): report of 110 consecutive cases

The objective of this retrospective study was to present long-term follow-up data for 110 consecutive children and young adults treated for a benign cerebellar astrocytoma at our institution between 1960 and 2001. Mean age at presentation was 8.9 years. The total surgical mortality was 9%, but declined from 16% in 1960-1977 to 0% in 1988-2001. At the close of the study 97/110 patients were still alive. Nine deaths were surgery related, 2 patients died of shunt-related causes and 2 patients died due to tumor recurrence. Five-, 10- and 25-year survival were 90, 89 and 85%, respectively. Multiple Cox regression analysis showed that tumor infiltration of the brain stem and the time period of surgery were the only explanatory variables significantly associated with survival. Five-year survival improved from 79% in the time period of 1960-1977 to 100% in the time period of 1988-2001. Tumor recurrence after total tumor resection was observed in 5 of 76 (7%) evaluable patients. Growth of residual tumor after subtotal tumor resection was observed in 7 of 26 (27%) evaluable patients. Recent followup MR revealed regression of residual tumor in 14 of 16 patients. Only 5 of these patients had received radiotherapy. Thus, spontaneous regression of residual tumor is a more frequent event than growth of residual tumor. The functional outcome was favorable in 82% of the patients [Karnofsky performance index (KPI) > or = 90]. Eighteen percent of the patients had moderate to severe disabilities (KPI 50-80).

CONCLUSIONS

Benign cerebellar astrocytoma is a surgical disease where the prognosis with respect to both survival and functional outcome is favorable. Spontaneous regression of residual tumor is frequently encountered, allowing for observation of residual tumors instead of performing a second resection in cases where a second resection carries a high risk of neurological sequelae.

Leptomeningeal dissemination of pilocytic astrocytoma via hematoma in a child

A case of recurrent pilocytic astrocytoma with leptomeningeal dissemination (LMD) is described. A cerebellar tumor was diagnosed in a 3-year-old boy, in whom resection was performed. When the boy was 6 years of age, recurrence was treated with surgery and local radiotherapy. At age 13 years, scoliosis was present, but the patient was asymptomatic. Twelve years after initial surgery LMD was demonstrated in the lumbar spinal region without recurrence of the original tumor. This tumor also was subtotally removed. During the procedure, a hematoma was observed adjacent to the tumor, but the border was clear. Histological examination of the spinal cord tumor showed features similar to those of the original tumor. There were no tumor cells in the hematoma. The MIB-1 labeling index indicated no malignant change compared with the previous samples. Radiotherapy was performed after the surgery. The importance of early diagnosis and management of scoliosis is emphasized, and the peculiar pattern of dissemination of the pilo-cytic astrocytoma and its treatment are reviewed.

Spinal cord pilocytic astrocytoma with cranial meningeal metastases

Dissemination of tumour cells along the cerebrospinal fluid (CSF) pathway has been reported mostly in medulloblastomas, germ cell tumours or high grade gliomas. Juvenile pilocytic astrocytoma (JPA) is usually a benign astrocytoma. However, drop metastases of indolent nature from intracranial tumours to the spinal cord are documented. All of the previously reported cases represent metastases of cerebellar or hypothalamic tumours spreading to the spinal cord. We document in this paper the first report of a spinal cord pilocytic astrocytoma spreading via the CSF to the cerebral meninges. A 9 year old girl had a JPA of C5 to C7 subtotally resected. Two and a half years later she presented with hydrocephalus with radiologically meningeal enhancement. The meninges were biopsied which showed metastatic JPA. The girl was relatively well 4 years after initial surgery with residual tumour. Spinal cord JPA can rarely metastasize to the cranial meninges. Similar to intracranial tumours which spread to the spinal cord, such metastatic lesions are indolent.