Clinical diagnostic and radiographic features of a primary intradural spinal chondrosarcoma in a young adult: illustrative case

Abstract

Background: Mesenchymal chondrosarcoma (MCS) is an aggressive subtype of chondrosarcoma that occurs extremely rarely in the central nervous system. Patients often present with pain or sensorimotor deficits, and resection is considered the gold standard. The role of adjuvant radiation and/or chemotherapy is largely unknown.

Observations: A 22-year-old male presented with a 4-month history of progressive back and bilateral leg pain. He underwent imaging workup with magnetic resonance imaging of the lumbar spine and was found to have an intradural, extramedullary, heterogeneously enhancing mass spanning the L4-5 vertebral levels. Intraoperatively, a lobular, partially calcified mass with a ventral dural attachment displacing the nerve roots laterally was observed. The mass was removed en bloc, and the patient later underwent adjuvant radiotherapy, with no evidence of recurrence 2 years following surgery.

Lessons: Spinal MCS is extremely rare and often presents with a more aggressive course than conventional chondrosarcoma. Radiological diagnosis is challenging, as the tumor mimics different pathologies. The presence of calcifications, heterogeneous enhancement, and a more rapid clinical course as well as the presence of HEY1::NCOA2 gene fusion, which can be detected by surrogate immunohistochemistry, aids in diagnosis. Resection is the standard of care, and adjuvant radiation may be considered to reduce local recurrence, although further studies are warranted.

Keywords: intradural extramedullary; mesenchymal chondrosarcoma; primary spinal tumors.

FIG. 1.

Preoperative sagittal T2-weighted (A), sagittal T1-weighted pre–gadolinium contrast (B), and sagittal T1-weighted postcontrast (C) magnetic resonance imaging (MRI) of the lumbar spine demonstrating a heterogeneously enhancing, T1-weighted isointense, T2-weighted hypointense lesion at L4–5 with a fatty cap at its superior aspect (white arrow).

FIG. 2.

Intraoperative photographs (A and B) of the reddish, calcified tumor within the dura displacing the nerve roots laterally. Gross view of the tumor after en bloc removal demonstrating the reddish-tan, variegated appearance (C). The ventral dura opening was closed in a watertight, running fashion (D), and the resection cavity demonstrated no apparent residual mass (E).

FIG. 3.

Hematoxylin-and-eosin staining showing sheets of poorly differentiated, small- to medium-sized tumor cells with high nuclear to cytoplasmic ratio and scant cytoplasm (A, original magnification ×200); islands of well-differentiated hyaline cartilage within a background of poorly differentiated tumor cells with a round to spindled morphology (B, original magnification ×100); and tumor cells arranged around vessels with a pericytoid vascular pattern (arrowheads, C, original magnification ×400). The neoplastic cells showed diffuse nuclear positivity for HEY1, confirming the presence of a HEY1::NCOA2 gene fusion (D, HEY1 immunohistochemical stain, original magnification ×400).

FIG. 4.

Postoperative MRI of the lumbar spine: Sagittal T2-weighted (A), sagittal T1-weighted pre–gadolinium contrast (B), and sagittal T1-weighted postcontrast (C) demonstrating no obvious residual mass and mild postsurgical enhancement of the resection bed.