Axial melorheostosis: A rare presentation.

Melorheostosis is a rare sclerosing bone dysplasia that most commonly affects the lower extremity long bones in a sclerotomal distribution. Melorheostosis of the spine is a particularly rare manifestation of this disease. In the appendicular skeleton, melorheostosis has a pathognomonic imaging appearance of flowing hyperostosis resembling melted candle wax flowing down the margins of a candlestick. In the spine, it can have a variety of imaging manifestations from unilateral focal sclerotic lesions resembling enostoses, to more bulky and deformative hyperostosis that span and fuse multiple adjacent spinal segments. This combination of nonaggressive radiologic features makes melorheostosis a particularly important diagnosis for radiologists to understand so that they may spare their patients unnecessary biopsy. Here we present the clinical features and computed tomography findings in a 33-year-old male with spinal melorheostosis involving the first and second cervical vertebrae.