Klippel–Feil syndrome associated with a craniocervico-thoracic dermoid cyst

BACKGROUND: Uncommonly, Klippel–Feil syndrome (KFS) has been associated with intracranial or spinal tumors, most frequently dermoid or epidermoid cysts. Although the associated dermoid cyst (DC) is usually located in the posterior fossa, isolated upper cervical DC has been reported. Extension from the posterior fossa to the upper cervical spine (C2) has been reported once. We report a rare case of KFS in association with a posterior fossa DC that extended down to the upper thoracic spine and review the current literature. CASE DESCRIPTION: A 47-year-old female with presented cervical myelopathy related to a cranio-cervico-thoracic DC in association with KPS-related cervicothoracic fusion (C2-T6) and thoracic kyphosis. The patient underwent complete tumor resection following sub-occipital craniectomy and C1-C4 cervical laminectomy. The patient exhibited complete resolution of symptoms with no tumor recurrence and no deformity at 6-year follow-up. CONCLUSION: DC should be added to the list of congenital central nervous system abnormalities, which should be sought in patients with KFS. Therefore, the presence of a cystic lesion in the posterior fossa, the craniocervical junction or the anterior cervical spine should suggest the possibility of a DC in patients with KFS. In cases of cranio-cervical DC, the tumor may extend quite far down the spinal column (reaching the thoracic spine), as demonstrated in the present case.