Malignant spindle cell tumors of the posterior fossa in children: case series and review of management

Meningeal melanocytoma of the central nervous system in children

PURPOSE

This study aimed to summarize the existing English-language literature on central nervous system (CNS) meningeal melanocytomas in children, and additionally describe our institutional case report.

METHODS

PubMed database was screened on September 2, 2024, for English-language papers reporting on pediatric patients with CNS meningeal melanocytoma.

RESULTS

A total of 17 papers reporting on 18 patients with 19 CNS meningeal melanocytomas were found in the literature. Additionally, we reported on a 15-year-old male patient with C2-C6 meningeal melanocytoma. Pediatric cohort analysis showed nearly equal sex distribution and a mean age at diagnosis of 11.9 years. There were fifteen intracranial (75%) and five spinal tumors (25%). Four lesions (20%) were diagnosed as intermediate-grade melanocytomas, while the remaining sixteen (80%) were benign meningeal melanocytomas. Most tumors were hyperintense on T1-weighted imaging (85%) and hypointense on T2-weighted imaging (73%). All tumors showed positivity for S100 and Melan-A. Most tumors were characterized by a lack of CNS invasion (91%). Gross-total resection (GTR) was performed in 61% of tumors. Adjuvant radiotherapy (RT) was applied in 50% of patients with incomplete tumor resection. Postoperatively, 62% of patients achieved a favorable outcome. We found 1, 2, 3, and 4-year overall survival of 80%, 71%, 71%, and 50%, respectively. The recurrence rate was 15% after a mean time of 10 months.

CONCLUSIONS

Meningeal melanocytomas constitute a rare subgroup of CNS tumors. Surgical tumor removal aiming at maximally safe GTR remains a standard approach, resulting in favorable postoperative outcomes. Considering high recurrence rate, long-term follow-up is needed.

Primary Ewing's Sarcoma affecting the Central Nervous System: A single-center experience and Narrative review

BACKGROUND AND OBJECTIVES

Ewing's sarcoma (EWS) is a malignant round-cell tumor arising from the bone and soft tissue. It is a disease of children and young adults. EWS affecting the central nervous system (cranial and spinal column) is relatively rare with an annual incidence of approximately one case per million in the Western population. Due to their rarity, very few studies are available in the literature. We present our experience of managing 21 such cases, highlighting their clinical, and radiological findings, treatment strategy, and surgical outcomes in patients with primary EWS affecting the central nervous system.

MATERIALS AND METHODS

We retrospectively collected hospital records of patients with primary EWS affecting the CNS (cranial and spinal column), who had been surgically treated in our Neuroscience Center between 2015 and 2023. Patients' demographics, presentation, radiological findings, treatment strategy including surgery and biopsy followed by adjuvant therapy, and outcome at discharge, and the latest follow-up were analyzed from our database.

RESULTS

There were sixteen male and five female patients with a mean age of 18.22 ± 12.73 years (ranging from 6 months to 59 years). The commonest presentation was headache and vomiting in cranial lesions (5/13 patients, 38.46%), and back pain in spinal lesions (4/8 patients, 50%). The site of lesions was cranial in thirteen patients (61.9%) and spinal column in eight patients (38.1%). The commonest site was the frontal region in the cranial group (6 patients, 46.15%) and the lumbar region in the spinal group (4 patients, 50%). All patients underwent surgical intervention [tumor resection (18) and biopsy (3)]. Tumor resection was achieved in 18 patients (85.71%). The extent of resection was gross-total excision in 9 patients (42.86%), near-total excision in 5 patients (23.8%), and tumor decompression in 4 patients (19%). Four patients underwent spinal instrumentation. Fifteen patients (71.42%) received multiagent chemo-radiotherapy according to institute protocol. Five patients (23.8%) with poor KPS expired within 6 months of surgery and could not receive adjuvant therapy. Two patients (9.52%) improved symptomatically, and nine patients (42.86%) remained asymptomatic at a mean follow-up of 25.1 ± 29 months. One patient (4.76%) after receiving 2 cycles of adjuvant therapy had initial improvement but expired later due to disease progression. Four patients after adjuvant chemo-radiotherapy (19%) expired due to systemic spread.

CONCLUSION

Primary EWS affecting the central nervous system is a rare variety. A detailed radiological assessment can aid in adequate planning for safe maximal resection. Timely tissue diagnosis is essential for initiating early treatment. Radical excision followed by adjuvant therapy offers a favorable outcome. Postoperative adjuvant chemo-radiotherapy aids in optimal disease control and surgical outcome. With the current treatment strategy, good surgical outcomes can be achieved. However, metastasis is not uncommon and should be evaluated regularly.

Primary Intracranial Spindle Cell Sarcoma, DICER1-Mutant, with MDM2 Amplification Diagnosed on the Basis of Extensive Molecular Profiling

Primary intracranial spindle cell sarcoma is an extremely rare mesenchymal tumor, the molecular pathogenesis of which is poorly understood. Because of the lack of specific markers, diagnosis sometimes relies on ruling out all possible differential diagnoses, often making it difficult to reach a definitive diagnosis. In this case study, we report a 69 year-old female patient for whom the integration of multi-layered molecular analyses contributed to making the diagnosis. The disease exhibited aggressive clinical behavior, requiring two sequential surgeries because of rapid regrowth within a short period. Primary and recurrent tumors exhibited similar histological features, in which spindle-shaped cells arranged in interlacing fascicles without any specific architectures, implicating sarcomatous tumors. In immunohistochemistry testing, tumor cells were immunopositive for vimentin but lacked any specific findings that contribute to narrowing down the differential diagnoses. Seeking further diagnostic clues, we performed DNA methylation-based analysis. The copy number analysis revealed MDM2 gene amplification and loss of heterozygosity of 22q. Moreover, dimension reduction clustering analysis implicated a methylation pattern comparable to aggressive types of sarcomas. In addition, an in-house next-generation sequencing panel ("Todai-OncoPanel") analysis identified somatic mutations in DICER1, NF2, and ATRX genes. Taken all together, we finally made the diagnosis of primary intracranial spindle cell sarcoma, DICER1-mutant, with MDM2 gene amplification. This case report suggests that even for the tumors with insufficient morphological and immuno-histological diagnostic clues, integration of multi-layered molecular analyses can contribute to making the diagnoses as well as to understanding the rare tumors by elucidating unexpected genetic and epigenetic features.