[Mesenchymal chondrosarcoma in central nervous system: a clinicopathological analysis]

Area of Science:

• Neuro-oncology
• Surgical pathology
• Molecular diagnostics

Background:

• Mesenchymal chondrosarcoma (MCS) is an exceptionally rare and aggressive tumor of the central nervous system (CNS).
• These tumors often involve the dura and can be mistaken for meningiomas on preoperative imaging, leading to diagnostic challenges.

Purpose of the Study:

• To investigate the clinicopathological features of central nervous system (CNS) mesenchymal chondrosarcoma (MCS).
• To evaluate the utility of NCOA2 gene rearrangement detection in diagnosing CNS MCS.

Main Methods:

• Retrospective review of nine CNS MCS cases, including clinical, imaging, histopathological, and immunohistochemical data.
• Fluorescence in situ hybridization (FISH) was used to detect NCOA2 gene rearrangement.
• Immunohistochemistry for SOX9, CD99, BRG1, INI1, and S-100 protein was performed.

Main Results:

• Six intracranial and three intraspinal tumors were identified, all with dural attachment.
• Histopathology revealed a biphasic pattern with small undifferentiated cells and hyaline cartilage.
• NCOA2 gene rearrangement was detected in 5/5 cases, and immunohistochemistry showed characteristic markers (SOX9, CD99, S-100).
• Three out of eight patients experienced recurrence within a year, and two died from the tumor.

Conclusions:

• Central nervous system mesenchymal chondrosarcoma is a rare, highly malignant neoplasm with a tendency for dural involvement.
• Preoperative imaging has limited accuracy in diagnosing CNS MCS, necessitating differentiation from other small round cell tumors and chondrosarcomas.
• FISH analysis for NCOA2 gene rearrangement is a valuable tool for the diagnosis of CNS MCS.