Phalanx-like osseous structure posterior to the cervical vertebrae: a hitherto unreported location for a rare anomaly

Several types of abnormalities of the vertebral column have been reported. Pelvic rib or pelvic digit is a rare congenital anomaly of the spine. A 58-year-old male patient presented with a complaint of a firm mass in the neck. He had no history of trauma and had been aware of the mass for years. Physical examination showed a painless and immobile mass in the neck, measuring 4x1 cm. About 10 to 15 degrees of restriction was noted in neck movements, with slight pain. A plain radiograph of the cervical region showed two bony formations resembling a coccygeal segment or a phalanx, posterior to the spinous process of the C6 vertebra. They had well-defined cortices and medullae and pseudo-articulation between each other and with the spinous process. These findings were confirmed by three-dimensional computed tomography and magnetic resonance images. The patient did not accept surgery for the lesions were not associated with a significant discomfort. To our knowledge, such a digit has hitherto not been reported in the cervical region.