Teaching Neuro <i>Images</i> : Chordoma

Abstract

A 30-year-old man presented with recurrent headaches. CT head revealed a clival chordoma (figure 1A). Chordomas originate from the embryonic remnants of the notochord and account for 2%–4% of all malignant bone tumors. They have a predilection for the axial skeleton, with 35% affecting the spheno-occipital region. The incidence peaks at ages 20–40 years. Male patients are affected twice as commonly as female patients.1 Clinical symptoms often result from local mass effect. On imaging, the tumor appears as a midline lesion and can contain heterogeneous calcifications. MRI demonstrates high signal on T2-weighted sequences and heterogeneous enhancement with a honeycomb appearance (figure 1).2 Indenting of the pons results in the characteristic thumb sign (figure 2). Differential diagnosis based on imaging appearance includes chondrosarcoma and metastasis.