Hematoma in the cervical ligamentum flavum. Report of a case and review of the literature.

Hematoma of the cervical ligamentum flavum is very rare, and its pathogenesis is unknown. We describe a case of ligamentum flavum hematoma in the cervical spine causing severe myelopathy. Postoperative histological examination suggested it was the result of the rupture of a hemangioma or of an arteriovenous malformation in the ligamentum flavum. After removal of the lesion, the patient's condition immediately improved. Review of all three reported cases, including this one, showed that complete resection of the mass resulted in immediate relief of symptoms of incomplete paraplegia. The findings of magnetic resonance imaging (MRI) of the hematoma may vary with time, and they may show no characteristic intensity. However, MRI of this case revealed that the tissues surrounding the mass were enhanced with gadolinium diethylene triamine penta-acetic acid, and an area of homogeneous iso-intensity was clearly surrounded by a low-intensity area (flavum) on T2-weighed short-tau inversion recovery images. These findings could be characteristic of the ligamentum flavum hematoma and might help in the differentiation from a cervical epidural hematoma.