Extra-Neural Metastases From Primary Intracranial Ependymomas: A Systematic Review

A systematic review of extraneural meningioma metastasis: timing, evolution and outlook

PURPOSE

Extraneural meningioma metastasis is a rare occurrence and may pose a clinical challenge due to its unclear prognosis. In this systematic review, we analyze patient demographics, clinical characteristics, management strategies, and outcomes.

METHODS

PubMed, EMBASE, Scopus, Cochrane, and Web of Science databases were searched from inception to February 23, 2024 for cases of metastatic meningioma according to PRISMA guidelines. Descriptive statistics, Mann-Whitney U test, Fisher's exact tests, Kaplan-Meier curves, and log-rank tests were used for selected analyses.

RESULTS

A total of 288 patients (52% male) were included with an average age of 49 years at meningioma diagnosis. Tumors were distributed across WHO grade 1 (38%), 2 (36%), and 3 (26%). Most patients experienced intracranial recurrence (79%) and mean time to first metastasis was approximately 8 years. No change in WHO grade between primary and metastasis was observed for most cases (65%). Treatment of the initial metastasis was most often with surgery (43%), chemotherapy (20%), or no treatment (14%). Half of the patients were alive (50%) with an average follow-up of 3 years following metastasis. Overall median survival was 36 months for the entire cohort. This differed significantly between WHO grade 1 versus 2/3 meningioma primaries (168 vs. 15 months, p < 0.005).

CONCLUSION

Metastatic meningioma appears to be associated with more positive prognosis than other brain tumor types with extra-neural metastasis or metastasis in general. This is particularly true for cases arising from a WHO grade 1 meningioma.

Recurrent intracranial anaplastic ependymoma with late-onset giant scalp metastasis

Key Clinical Message

Ependymomas are primary brain tumors that predominantly affect individuals between 0 and 4 years of age. Although ependymomas have a propensity for recurrence and the potential to spread within the central nervous system through cerebrospinal fluid (resulting in drop metastases), reports of extra-neural metastatic localizations are exceedingly rare in the existing literature. This case report presents a unique and rare instance of recurrent intracranial anaplastic ependymoma with a late-onset giant scalp metastasis.

Abstract

A 55-year-old male patient with a medical history of partial resection of an atypical supratentorial left temporal ependymoma presented with a recurrent anaplastic ependymoma, which had been managed with surgery and radiotherapy. After a 4-year follow-up, the patient developed a subcutaneous mass in the left parietal region of the scalp. A multidisciplinary team of neurosurgeons and plastic surgeons performed a surgical procedure, which included en bloc removal of the scalp lesion, resection of 1 cm of unaffected skin, and craniotomy to address an osteolytic area in the parietal skull bone. Skin autografts were used for reconstruction. Histological examination confirmed metastasis of anaplastic ependymoma in the scalp. After a delay in starting chemotherapy due to concerns related to the COVID-19 pandemic, the patient eventually initiated chemotherapy, leading to disease stability at a short-term follow-up. Scalp metastases from ependymoma are rarely reported in the literature. Management of such cases necessitates aggressive surgical resection, followed by adjuvant chemotherapy and radiotherapy. A multidisciplinary approach is recommended to ensure effective and targeted therapy, with a focus on preserving aesthetics, particularly in pediatric cases.

A Pediatric Case of Extraneural Subcutaneous Metastasis of Ependymoma

Ependymoma is the third most common brain tumor in children. Extracranial metastases of ependymomas are uncommon. A 21-month-old Japanese boy was diagnosed to be brain dead due to a posterior fossa (PF) brain tumor. Surgical resection of the tumor was not performed. Twenty-seven months later, he developed a truncal subcutaneous tumor, which was pathologically diagnosed as PF ependymoma group A. We observed the intracranial recurrence of the brain tumor, an invasion to the left orbit, and a neoplasm in his liver before he died. This case suggests that PF ependymoma group A can metastasize extracranially to various organs.

Acute disseminated encephalomyelitis and viral encephalitis: An unusual and misleading imaging

Acute disseminated encephalomyelitis (ADEM) is a rare illness. It is characterized by different presentations like encephalopathy, seizures, hemiplegia, and visual symptoms. We present a patient who presented seizures and encephalopathy. Brain MRI showed symmetrical white and gray matter lesions. He was treated with acyclovir for viral encephalitis and given immunotherapy for ADEM. The radiological findings may be inconclusive in some cases, hence differential diagnosis of both viral encephalitis and ADEM needs to be considered. Early immunotherapy is required in such fulminant cases.

Application of Drug Testing Platforms in Circulating Tumor Cells and Validation of a Patient-Derived Xenograft Mouse Model in Patient with Primary Intracranial Ependymomas with Extraneural Metastases

Primary intracranial ependymoma is a challenging tumor to treat despite the availability of multidisciplinary therapeutic modalities, including surgical resection, radiotherapy, and adjuvant chemotherapy. After the completion of initial treatment, when resistant tumor cells recur, salvage therapy needs to be carried out with a more precise strategy. Circulating tumor cells (CTCs) have specifically been detected and validated for patients with primary or recurrent diffused glioma. The CTC drug screening platform can be used to perform a mini-invasive liquid biopsy for potential drug selection. The validation of potential drugs in a patient-derived xenograft (PDX) mouse model based on the same patient can serve as a preclinical testing platform. Here, we present the application of a drug testing model in a six-year-old girl with primary ependymoma on the posterior fossa, type A (EPN-PFA). She suffered from tumor recurrence with intracranial and spinal seeding at 2 years after her first operation and extraneural metastases in the pleura, lung, mediastinum, and distant femoral bone at 4 years after initial treatment. The CTC screening platform results showed that everolimus and entrectinib could be used to decrease CTC viability. The therapeutic efficacy of these two therapeutic agents has also been validated in a PDX mouse model from the same patient, and the results showed that these two therapeutic agents significantly decreased tumor growth. After precise drug screening and the combination of focal radiation on the femoral bone with everolimus chemotherapy, the whole-body bone scan showed significant shrinkage of the metastatic tumor on the right femoral bone. This novel approach can combine liquid biopsy, CTC drug testing platforms, and PDX model validation to achieve precision medicine in rare and challenging tumors with extraneural metastases.