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

Abstract

OBJECTIVE The WHO Classification of Tumours of the Central Nervous System (2016) classifies nonmeningothelial malignant spindle cell tumors involving the extraaxial tissues of the posterior fossa as melanocytic tumors and malignant mesenchymal tumors (sarcomas). The objective of this study was to conduct a review of the literature pertaining to the management strategies of posterior fossa malignant spindle cell tumors in the pediatric population. METHODS The authors performed an institutional search of their pathology database for patients younger than 18 years of age who presented with posterior fossa malignant spindle cell tumors. A literature review was also performed using the PubMed database, with “posterior fossa” or “spindle cell tumors” or “Ewing sarcoma” or “high-grade” or “spindle cell sarcoma” or “leptomeningeal melanocytoma” as keywords. The database search was restricted to pediatric patients (age ≤ 18 years). Parameters reported from the literature review included patient age, tumor location, presenting symptoms, treatment modalities (resection, chemotherapy, and/or radiotherapy), leptomeningeal spread at or after the time of treatment, and follow-up length and resulting outcome. RESULTS The authors report 3 rare cases of posterior fossa malignant spindle cell tumors, including Ewing sarcoma in a 13-year-old male; high-grade spindle cell sarcoma, not otherwise specified in a 10-year-old male; and primary leptomeningeal melanocytoma in a 16-year-old female. All 3 patients underwent resection and radiotherapy and either chemotherapy or targeted immunotherapy. At the last follow-up, all patients were alive with either resolution or stable disease. CONCLUSIONS A review of these 3 cases and the existing literature support managing patients with intracranial malignant spindle cell tumors with multimodal therapy that can include a combination of resection, radiotherapy, and chemotherapy or immunotherapy to prolong progression-free and overall survival.

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

“…Primary intracranial spindle cell sarcoma (IC-SCS) is an extremely rare mesenchymal tumor; only a limited number of cases have been reported in the literature to date. 1 - 4 The tumor is considered to originate from fibroblastic elements within the brain parenchyma or its meningeal coverings. 3 Because of its rarity, its molecular pathogenesis remains poorly understood.…”

“… 1 - 4 The tumor is considered to originate from fibroblastic elements within the brain parenchyma or its meningeal coverings. 3 Because of its rarity, its molecular pathogenesis remains poorly understood. Patients with IC-SCS are treated on a case-by-case basis.…”

“…5 Therefore, the prognosis of patients with the disease is generally poor. 3 Recently, next-generation sequencing techniques have been incorporated in clinical practice. 6,7 At our institution, a platform for DNA and RNA targeted panel sequencing, named as "Todai-OncoPanel" (TOP), has also been launched and prospectively tested to improve our understanding of the molecular background of diseases and identify therapeutic targets.…”