A 50-year-old man presenting with a pelvic mass extending into the inferior vena cava (SUVmax 13.97) was diagnosed with mesenchymal chondrosarcoma confirmed by a HEY1::NCOA2 fusion.
Case Report (n=1)
A rare case of mesenchymal chondrosarcoma presenting as a calcified mass extending into the inferior vena cava, confirmed by HEY1::NCOA2 fusion.
A 50-year-old man presented with lower abdominal pain. Imaging revealed a pelvic mass extending from the right internal iliac vein into the inferior vena cava. Fluorodeoxyglucose-positron emission tomography revealed intense uptake (SUVmax 13.97) without metastasis. Biopsy revealed a biphasic tumor with cartilaginous matrix and staghorn vasculature. Immunohistochemistry indicated positive for SMA, desmin, MyoD1, and NKX3.1. Moreover, genomic analysis identified a HEY1::NCOA2 fusion, confirming mesenchymal chondrosarcoma (MCS). Given the extent of the tumor, chemoradiotherapy was initiated. MCS is a rare, high-grade sarcoma with limited treatment options. Targeted therapies against HEY1::NCOA2-associated pathways are promising and are currently under investigation.
Ichikawa et al. (2026) conducted a case report in Mesenchymal chondrosarcoma (n=1). Chemoradiotherapy was evaluated. A 50-year-old man presenting with a pelvic mass extending into the inferior vena cava (SUVmax 13.97) was diagnosed with mesenchymal chondrosarcoma confirmed by a HEY1::NCOA2 fusion.