Capillary hemangioma is a benign vascular neoplasm commonly involving the skin, soft tissue and mucosal membranes of the head and neck region (4). Central nervous system (CNS) involvement is relatively uncommon, but is a recognized occurrence. Spinal intradural extramedullary capillary hemangiomas are extremely rare (3), Complete resection is the treatment of choice and follow-up of 10 patients demonstrated no clinical recurrence in the neuraxis (1). However, amongst the additional nine cases reported since 2005 (2, 4) is the recent case of recurrent capillary hemangioma of the spinal cord in a 48 year old man that developed 6 months after the first operation.
Spinal level capillary hemangiomas have been reported in adults and adolescents. These tumors can occur in the thoracic area or in close relation to the conus medullaris and nerve roots of the cauda equina. Clinical presentation and radiologic appearance of spinal intradural extramedullary capillary hemangiomas are similar to those of more common intradural lesions of the same location (2). These lesions are usually encapsulated and well demarcated from the surrounding parenchyma of the spinal cord and affected nerve roots (4). Although the presence of enlarged vasculature may be a useful clue, the magnetic resonance imaging appearance is often nonspecific (2). Therefore, capillary hemangioma should be included in the differential diagnosis of any enhancing intradural extramedullary mass.
Several pathogenic mechanisms have been proposed for capillary hemangiomas of the CNS: a) Impaired movement and differentiation of primitive mesoderm from the embryonic mesodermal plate during the early somitic differentiation (days 21-24 of embryogenesis); b) Vascular tumors of the conus-cauda region have been defined as hamartomas, implying their congenital origin; c) Abnormal development of vascular structures within the epineurium of the nerve roots may be affected (4).
Histological and immunohistochemical features of CNS capillary hemangiomas have been reported to be similar to those arising in the skin. The CNS lesions showed a lobular architecture with fibrous tissue septa and highly cellular areas in six cases, whereas a blood-filled cavernous space and fibroendothelial papillae mimicking papillary endothelial hyperplasia were seen in four cases. Immunohistochemistry demonstrated expression of vascular endothelial growth factor and glucocorticoid receptor (1). Our case showed the typical histologic features of a capillary hemangioma and the immunophenotype was characteristic for a vascular-derived tumor.
The Ki-67 proliferative index of CNS capillary hemangiomas has been reported to range from 2.2 to 12% (mean 5.6%) (1), while the recently reported case of recurrent capillary hemangioma had a proliferative index of 10%. Although the prognostic significance of the high proliferative index of 34% in our case is unclear, this finding indicates that close follow-up of the patient may be warranted.
Contributed by Gulisa Turashvili, MD, PhD, Sonal Varma, MD, Sandip SenGupta, MD, John P. Rossiter, MB, BCh, PhD