Sacral Chordoma: Multimodality Imaging and Radiologic-Pathologic Correlation of a Rare Malignant Sacral Tumor.

Chordoma is a rare malignant tumor arising from embryonic notochordal remnants and most commonly involves the sacrococcygeal region. Because of its slow-growing nature and nonspecific clinical presentation, diagnosis is often delayed until significant local extension occurs. Imaging plays a crucial role in lesion detection, characterization, and surgical planning. We report a case of sacral chordoma in a 63-year-old woman presenting with chronic sacral pain and constipation. Initial radiographs were subtle, demonstrating non-visualization of the distal sacral segments and ill-defined sacral soft tissue fullness. CT revealed a large destructive lytic lesion involving the sacrum from S2 to the distal sacrococcygeal segments with internal chunky calcifications, sacral canal involvement, and bulky presacral extension. MRI demonstrated a lobulated mass with iso- to hypointense T1 signal, heterogeneous T2/short TI inversion recovery (STIR) hyperintensity, diffusion restriction, and avid heterogeneous enhancement with central non-enhancing areas. Histopathology confirmed chordoma with characteristic physaliphorous cells embedded in a myxoid stroma. This case highlights the characteristic multimodality imaging appearance of sacral chordoma and emphasizes the importance of radiologic-pathologic correlation in establishing diagnosis and narrowing the differential considerations.