Clival Chordoma, Arising in Pre-existing Benign Notochordal Cell Tumor, Case Report

Abstract

Lesions of notochordal origin are unusual surgical cases that have a broad spectrum of differentiation, from remnants to benign tumors -namely “benign notochordal cell tumor BNCT”- to malignant chordoma. These lesions arise within the vertebral bodies at the ends of axial skeleton, clivus and lumbar areas. Chordoma, is a malignant destructive lesion extending from bone to surrounding soft tissue. It is hypothesized to arise from its rare benign counterpart, BNCT as evidenced by their co-existence in rare case reports, in lumbar area, an even more rare in clival region. These benign forms are even scarce to see in surgical pathology specimen and carry a histological resemblance in morphology to malignant chordoma if not recognized. Here, we report a case of chordoma arising from a benign notochordal cell tumor (BNCT), which was discovered in a 35 years old male who presented with diplopia, diagnosed as 6^th nerve palsy. MRI imaging showed an expansile clival lesion with sclerotic borders invading the cavernous sinus and encasing the carotid. Histopathology showed features of chordoma within BNCT. This case highlights the rarity of the entity especially in the clival region, the wide differential diagnosis of clear cell tumor arising in the clival region and the importance of radio-pathological correlation.