[Extraskeletal mesenchymal chondrosarcoma in central nerve system: a clinicopathological analysis]

Area of Science:

• Oncology
• Neuropathology
• Molecular Genetics

Background:

• Extraskeletal mesenchymal chondrosarcoma is a rare tumor affecting the central nervous system (CNS).
• Limited data exists on its clinicopathological, immunophenotypic, and molecular characteristics.
• Understanding these features is crucial for accurate diagnosis and prognosis.

Purpose of the Study:

• To investigate the clinicopathological features, immunophenotype, molecular genetics, and prognosis of CNS extraskeletal mesenchymal chondrosarcoma.
• To identify potential diagnostic markers for this rare CNS tumor.

Main Methods:

• Retrospective review of four CNS extraskeletal mesenchymal chondrosarcoma cases.
• Analysis included histopathology, immunohistochemistry, and molecular genetic analysis (HEY1-NCOA2 fusion).
• Clinical data and follow-up information were collected.

Main Results:

• Patients aged 20-35 years, with three intracranial and one intradural lesion.
• Histology showed small undifferentiated cells with hyaline cartilage islands, hemangiopericytoma-like pattern, calcification, and ossification.
• Immunohistochemistry revealed VIM+, SOX9+, CD99+, NSE+, NKX3.1+, S-100+, and negative for CKpan, EMA, desmin.
• HEY1-NCOA2 fusion transcripts were identified in three cases.
• Two patients showed no recurrence or metastasis at 8 and 20 months post-follow-up.

Conclusions:

• Extraskeletal mesenchymal chondrosarcoma is a rare CNS disease with a generally poor prognosis.
• NKX3.1 may serve as a useful diagnostic marker alongside SOX9.
• Accurate diagnosis relies on integrating pathological, immunophenotypic, and genetic findings.