Intraosseous Hemangioma
An intraosseous hemangioma is a rare benign vascular tumor occurring within bone, representing approximately 0.5-1% of all bone tumors, most commonly affecting the vertebral skeleton and skull, with a predilection for adult women in their fourth decade of life. 1, 2
Definition and Classification
Intraosseous hemangiomas are described as benign vasoformative neoplasms or hamartomatous proliferations of endothelial cells forming a vascular network with intermixed fibrous connective tissue stroma. 1 These lesions are distinct from infantile hemangiomas, which are soft tissue vascular tumors of infancy that appear in the first weeks of life and undergo characteristic proliferation and involution phases. 3
Four Histologic Variants
- Capillary type: composed of small, capillary-sized vessels 1
- Cavernous type: contains large, dilated vascular spaces 1, 2
- Mixed variant: combination of capillary and cavernous elements 1
- Scirrhous type: prominent fibrous tissue component 1
Anatomic Distribution
Most Common Sites
- Vertebral skeleton: most frequent location overall 1, 2
- Calvarium: when occurring in the skull, primarily affects frontal and parietal bones 1, 4, 2
- Facial bones: rare, with involvement of maxilla, mandible, nasal bones, and zygoma 1, 5, 6
Skull Base Involvement
- Clivus: extremely rare location, with only a few reported cases 4
- Zygoma: uncommon site with approximately 49 case reports in the literature as of 2017 1
Clinical Presentation
The typical patient is a woman in her fourth decade presenting with a firm, painless swelling. 1, 2 The mean age at presentation is 32.7 years with a female-to-male ratio of 1.4:1. 2
Common Presenting Features
- Local growth or swelling: most common initial manifestation 2
- Headache: second most common symptom 2
- Painless mass: characteristic presentation 1
- Incidental finding: increasingly discovered on imaging performed for other reasons 4
Etiology and Pathogenesis
Prior trauma to the affected area is believed to be the most common etiologic factor. 1 The exact pathogenesis remains incompletely understood, but these lesions represent true benign vascular proliferations rather than malformations. 1, 2
Radiographic Features
Characteristic Imaging Patterns
- Osteolytic, intradiploic masses: typical appearance on CT 2, 5
- Trabeculations: creating "honeycomb" or "starburst" pattern, which is highly characteristic 2, 5
- Contrast enhancement: typically enhances after contrast administration 2, 5
- MRI features: documented signal characteristics help differentiate from other lesions 5, 6
Critical Clinical Pitfall
These lesions have a tendency to bleed briskly upon removal or biopsy, making preoperative detection of their vascular nature critically important for surgical planning. 1 Failure to recognize the vascular nature preoperatively can lead to significant intraoperative hemorrhage.
Management Approach
Calvarial Lesions
- Complete surgical excision: craniectomy or en bloc resection with skull reconstruction is the treatment of choice 2
- Preoperative embolization: recommended for large tumors to minimize intraoperative blood loss 2
Skull Base Lesions
- Transsphenoidal approach: used for clival/sellar lesions 2
- Partial resection: may be acceptable given benign nature 2
Prognosis
No tumor recurrence has been reported at mean follow-up of 39 months, even after subtotal resection, reflecting the benign nature of these lesions. 2 Maximal safe resection is recommended as the treatment of choice. 2
Key Distinguishing Features from Infantile Hemangiomas
Intraosseous hemangiomas should not be confused with infantile hemangiomas (IHs), which are entirely different entities. 3 IHs are soft tissue vascular tumors that: