Objective: Most vertebral hemangiomas contain high signal intensity on T1-weighted MRI images. Atypical vertebral hemangiomas, which are defined as showing low-signal intensity on T1-weighted images, have been described as lesions which are prone to aggressive behavior. This study was performed to assess behavior of atypical hemangiomas.
Materials and methods: Thoracic and lumbar spine MRI reports for the year 2012 were reviewed for diagnosis of atypical hemangioma. Images were reviewed by two independent observers, and cases which showed atypical vertebral hemangioma, and had imaging or clinical follow-up, were included in our study.
Results: Thirty atypical hemangiomas which had follow-up data were identified out of 2784 thoracic and lumbar MR examinations performed during 2012 at a single institution. Imaging follow-up was available for 23 lesions (mean follow-up 32 months), while there was clinical follow-up for the remaining seven lesions (mean 43.6 months). Twenty-two lesions were stable on imaging, while one demonstrated significant growth over approximately 6 years, developing MRI signal characteristics of a typical hemangioma. Eleven lesions had CT scans showing typical features of hemangioma. Two of the index lesions could not be identified on follow-up CT examinations, which showed normal-appearing spines. The remaining seven lesions were followed clinically; none of the patients reported symptoms in the region of the index lesions.
Conclusions: Atypical hemangiomas are uncommon lesions. The cases in our population did not show aggressive behavior. A more appropriate designation for these lesions may be lipid-poor hemangioma, to distinguish them from aggressive hemangiomas.
Keywords: Aggressive hemangioma; Atypical hemangioma; Vertebral hemangioma.