Presenter

Shervin Pejhan

Authors

Shervin Pejhan1, Jeff Terry2, Jon Bush2, Tony Ng3, Christopher Dunham2

1University of Western Ontario

2University of British Columbia, Division of Anatomic Pathology, BC Children’s Hospital (BCCH)

3University of British Columbia, Division of Anatomic Pathology, Vancouver General Hospital (VGH)

Conflict of Interest

I do not have a relationship with a for-profit and/or a not-for-profit organization to disclose.

Clinical Summary

A previously well, 11-year-old boy, began developing back pain and tripping while playing basketball 3 weeks prior to surgery. Back pain and left leg weakness led to visits with a chiropractor and physiotherapy. This weakness subsequently progressed to involve both legs after 2 weeks and became so severe he required crutches and could not stand without assistance. Urinary incontinence prompted presentation to the emergency department at an outside hospital. Abdominal ultrasound, x-rays of the pelvis and abdomen, and urine studies were performed, and the patient was diagnosed with “slipped capital femoral epiphysis”. An MRI was scheduled, but worsening symptoms including progressive weakness and sensory loss in both legs, as well as urinary incontinence, prompted early re-presentation to the same emergency department. An MRI at that time revealed a well circumscribed 9 x 6 x 6 mm intradural extramedullary mass anterior to the thoracic spinal cord. There was no involvement of the neural exit foramina. The mass was T1 and T2 isointense and demonstrated intense homogenous enhancement. Despite significant compression, only minimal T2 hyperintensity was detected in the adjacent spinal cord.

The patient was transferred to BCCH and underwent surgery involving a T4 laminectomy and decompression. The left T4 pedicle was resected in order to access the tumor. T3-5 posterior instrumentation and fusion was performed to stabilize the spine and a gross total resection was thought to be achieved.

Discussion points

  1. Diagnosis?
  2. Molecular alteration?
  3. Any additional therapy required?
Reveal Diagnosis

Mesenchymal chondrosarcoma, HEY1(exon4)::NCOA2(exon13)

Additional relevant investigations and comment.
Nanostring sarcoma panel (Dr. Tony Ng) uncovered a diagnostic HEY1(exon4)::NCOA2(exon13) fusion

References
1. Arora K, Riddle ND. Extraskeletal Mesenchymal Chondrosarcoma. Arch Pathol Lab Med 2018;142:1421-4.
2. Chatterjee D, Radotra BD, Madan R, et al. Extraskeletal Mesenchymal Chondrosarcoma of Central Nervous System – A Rare
but Aggressive Tumor: Analysis of Five Cases. Neurol India 2022;70:285-8.
3. Derenda M, Borof D, Kowalina I, et al. Primary Spinal Intradural Mesenchymal Chondrosarcoma with Several Local
Regrowths Treated with Osteoplastic Laminotomies: A Case Report. Surg J (N Y) 2017;3:e117-e23.
4. Xu B, Rooper LM, Dermawan JK, et al. Mesenchymal chondrosarcoma of the head and neck with HEY1::NCOA2 fusion: A
clinicopathologic and molecular study of 13 cases with emphasis on diagnostic pitfalls. Genes Chromosomes Cancer
2022;61:670-7.
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