Thoracolumbar Arachnoid Cyst with Horner Syndrome: A Case Report and Review of the Literature.

Horner syndrome (HS) results from the interruption of sympathic pathway, and the patients have a group of signs including miosis, ptosis, enophthalmos, and anhydrosis. While HS is mainly caused by cervical sympathetic nerve injury such as sympathetic chain tumor, we report here a HS case caused by a thoracolumbar arachnoid cyst. Imageological examination showed the cyst existed in spinal canal from the T11 to L3 level, which was further confirmed by operation. The tumor attacked the lateral margin of intervertebral foramen at certain stages. In MRI scan, no abnormality was found in the patient's crania, cervical vertebra, thoracic vertebra, or the other parts. After removal of the cyst with operation, the patient's HS symptoms and weakness of lower limbs were relieved apparently. Although the sympathetic center origins from the cornu laterale medullae spinalis of T1 to L3, there are many reports about HS caused by lumbar anesthesia and epidural anesthesia according to our literature review, and there is no report about HS results from intraspinal space-occupying lesion below T11 level. Our finding suggests that when the sympathetic center below the level of T11 emits nerve to dominate abdominal viscera, it can also control the sweat glands from face to feet, including pupils and eyelids. When physicians encounter patients with HS and one side of the body and abdominal viscera sympathetic syndromes, the pathological changes in lower thoracic vertebra or lumbar vertebra should be taken in consideration.