YO7 - Intracranial Extra-skeletal Myxoid Chondrosarcoma with EWSR1 gene fusion

Case summary

BACKGROUND:

Intracranial extra skeletal myxoid chondrosarcoma is an extremely rare entity and are thought to arise from the choroid plexus, dura or in rare instances from the pineal region.They constitute a distinct genomic entity characterized by reciprocal translocation of fusion genes, most commonly EWSR1 in 22q12 with NR4A3 in 9q2-q31.1.They are considered to have a high risk of local recurrence and potential for metastasis. Here we report a case of intraventricular myxoid chondrosarcoma in a young male, who underwent surgery and adjuvant radiation.

CASE SUMMARY:

A 27 year old male, evaluated for complaints of headache, seizures and pain in the neck, MRI whole spine was normal. MRI Brain showed a lesion in right lateral ventricle. He underwent right parieto occipital craniotomy with subtotal excision. Postop HPE was Ependymoma, WHO grade II. Referred to our institute for further management. Systemic examination was unremarkable. Postop MRI Brain showed no evidence of focal enhancing areas with post operative gliosis in right parietal lobe communicating with right lateral ventricle with dilated temporal and occipital horns.

Blocks and slides review along with IHC revealed vimentin and CD99 positive while GFAP, pancytokeratin, CD 34, S100 negative, Ki 67 low. FISH for EWSR1 gene positive. Final possibilities were Myxoid Chondrosarcoma or Primary Intracerebral myxoid neoplasm with EWSR1 fusion.

Discussed in multidisciplinary board and planned for adjuvant radiation. A total dose of 5400cGy in 30 fractions at 180cGy per fraction was delivered using 6MV photons with IGRT technique. Patient tolerated treatment well with grade 1 skin reactions and alopecia. At 9 months post radiotherapy, patient is asymptomatic and MRI Brain appears normal.

DISCUSSION:

Based on literature review, 13 cases of intra cranial extraskeletal myxoid chondrosarcoma has been reported till date since its first description in 1972. This would be the 14th case overall and second case of intraventricular origin to be reported till date. Owing to its rarity and limited literature, there is no standard treatment guidelines available. Combined modality approach with surgery followed by radiotherapy provides good local control with low morbidity.

Clinical trial identification

Editorial acknowledgement