Diagnostic pitfall in the diagnosis of mesenchymal chondrosarcoma arising in the central nervous system

Abstract

Mesenchymal chondrosarcoma is a rare aggressive neoplasm typically affecting the bones of young adults. It may also arise in somatic soft tissue, the CNS and other organs. It has a characteristic biphasic histological pattern composed of highly undifferentiated small round cells and islands of well-differentiated hyaline cartilage. We report a case of mesenchymal chondrosarcoma arising from the right tentorium cerebelli in a 21-year-old woman with symptoms relating to mass effect. Histological examination demonstrated a purely small round cell appearance in a specimen obtained during partial resection at an outside institution, leading to an erroneous diagnosis of Ewing sarcoma/primitive neuroectodermal tumor (PNET). The diagnosis of mesenchymal chondrosarcoma was made only after tissue obtained during a definitive complete macroscopic removal involving the regional tentorium cerebelli, transverse and sigmoid dural venous sinuses which showed a prominent cartilaginous component. We discuss the features of mesenchymal chondrosarcoma arising in the CNS, the important differential diagnoses of small round-cell tumors within the CNS, and the differentiating features of mesenchymal chondrosarcoma from Ewing sarcoma/PNET, medulloblastoma, hemangiopericytoma, monophasic synovial sarcoma and atypical teratoid/rhabdoid tumour.

Primary paediatric epidural sarcomas: molecular exploration of three cases

“…Presently, its developmental mechanisms remain poorly understood. Clinical experience with CNS-related MCS is also extremely limited; nonetheless, local recurrence and distant metastasis has been reported [7]. Presently, CNS-based MCS has only been reflected in surgical case reports and small series in the literature [7–15].…”

“…Clinical experience with CNS-related MCS is also extremely limited; nonetheless, local recurrence and distant metastasis has been reported [7]. Presently, CNS-based MCS has only been reflected in surgical case reports and small series in the literature [7–15]. Recently, the HEY1 (exon 4)-NCOA2 (exon 13) gene fusion is reported as a recurrent event unique to all MCS [16, 17].…”

A rare tentorial mesenchymal chondrosarcoma in posterior cranial fossa: Case report

“…However, in mesenchymal chondrosarcoma, it is easier to find patchy-like calcifications, which are rarely seen in hemangiopericytoma [5]. PNET are most seen as extra-axial, dural-based masses with a tendency to affect a younger population, with the peak incidence in the second decade [6][7][8]. It is really challenging to distinguish extraskeletal mesenchymal chondrosarcoma from PNET based on the traditional MRI or CT.…”

Intraspinal dural‐based primary osteoblastoma with aneurysmal bone cyst‐like change

“…Osteocartilaginous tumors are exceedingly rare, are usually dural‐based, develop in the skull and only secondarily displace dura and brain . To our knowledge, extraosseous osteoma, chondroma, osteochondroma, mesenchymal chondrosarcoma, osteosarcoma and aneurysmal bone cyst have been seldom described in the CNS. A few cases of unusual dura‐based periosteal osteoblastoma have also been reported in cranial bones, such as temporal bone and frontal cranial bone .…”