Intraosseous Hemangioma of the Skull with Dural Tail Sign: Radiologic Features with Pathologic Correlation

Correlation of T1-weighted contrast-enhanced MR image (A) with gross formalin-fixed specimen. Gross examination after formalin fixation shows a brown–red mass in the diploe, with radiated spicules and disruption of the outer and inner table (B); the bulk of the intra- and extracranial mass is missing as a result of the surgical excision technique. In the histomorphological representative section of the extraosseous fraction of the lesion (C), the fat cells (*) are seen as clear spaces without rimming; the vessels (§) are irregularly shaped dilated spaces lined by a single layer of inconspicuous endothelial cells (arrow) and often filled with erythrocytes (#) (hematoxylin and eosin, original magnification ×40). The vessels are arranged in a diffuse haphazard pattern. No signs of thrombosis or bleeding are seen. Intraosseous fraction (D) shows the hemangioma lying between plump bony trabeculae (double arrows) in irregularly shaped marrow spaces (hematoxylin and eosin, original magnification ×20). Immunohistochemically, the antibodies were directed against vimentin, which labels all mesenchymal cells (ie, all vessel walls and fat cells) (E), and CD34 (F), which labels endothelial cells (immunoperoxidase/diaminobenzidine method, original magnification ×100). In the correlation of the T1-weighted contrast-enhanced MR image with the histologic specimen at the site of dural tail sign (G), the dura is not invaded by the lesion; instead, the lesion grew along the inner surface of the skull. The van Gieson stain labels the cavernous hemangioma yellow–brown (mesenchymal component [μ]) and the collagenous fibers red (dura matter [$]). The arrow indicates the sharp delineation of the hemangioma (original magnification, ×20).