Syrinx refers to a fluid (cerebrospinal fluid) filled cavity in the spinal cord. A small syrinx either may not cause any symptoms or cause only minor symptoms, and therefore, they remain undiagnosed for long. They get detected when MRI spine is done for evaluation of neck pain, or other symptoms.
In the MRI of cervical spine above, you can see hyperintense CSF-filled cavity extending from C6 to D1, which is suggestive of a syrinx. She had no specific symptoms or signs of syrinx.
Common symptoms of cervical cord syrinx/syringomyelia: 1. Dissociated sensory loss- loss of pain and temperature sensations, with preserved touch sensation, 2. Suspended sensory loss in a cape like distribution, 3. Trophic changes over hands, 4. Wasting of small muscles of hands, 5. Bowel and bladder dysfunction. Surgery is needed, if these symptoms are present.
In this case, syrinx was idiopathic and was not causing any symptoms, so no surgery was advised.