Calcaneal cysts and lipomas are relatively rare, benign bone lesions. They are similar in many ways, including in their location and radiological appearance, but their content differs. Cysts contain fluid whereas lipomas contain fat, although some lesions may exhibit a mixed content. The pathogenesis of the two entities is the subject of controversy. The theory that calcaneal cysts may result from lipomatous necrosis has been widely suggested in the literature, but no such progression has eve...

This case reports a 25-year-old woman initially diagnosed with adjacent benign notochordal cell tumors (BNCTs) of L3 and L4 based on needle biopsy of L3 and stable imaging over a 3-year period who was ultimately found to have a chordoma arising from a BNCT at L3. It illustrates the potential relationship between benign and malignant notochordal tumors and the difficulty in distinguishing them by clinical, radiological, and even histopathological means.