Background

Primary intraosseous cavernous hemangiomas (PICHs) are a rare and infrequent tumor representing 0.7 to 1.0% of all bone tumors [1]. PICHs are usually found in the spine and rarely appear in the vault cranial, being 0.2% of cranial bone tumors [2]. The first description of this type of tumors was in 1845 by Toynbee. A review of the literature reveals about 100 published cases and a growing trend every year (Table 1) [3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77]. These tumors are seen mostly in middle age, with a peak around the fourth decade and a male/female ratio that ranges between 3:1 and 2:1 [2].

Table 1 Review of the literature from 1845 to 2016 of the published cases of intraosseous hemangiomas
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Case report

We are dealing with a 57-year-old patient, with no history of interest, referred to our Service for surgical assessment. It had presented, for 4.5 years, a small tumor in the left front region of 1.5 cm in diameter, which had slowly increased in size (Fig. 1c, d). During the examination, a mass of solid and hard consistency, painless and adhered to deep planes, was palpated under a normal-looking skin. The plain radiograph (Fig. 1a, b) and the CT (Fig. 1d) showed a left frontal intraosseous lesion with osteolytic characteristics with moderate aggressiveness. The radiological differential diagnosis included bone metastasis or plasmacytoma. The systemic studies of tumor tracking (blood count, hematological smear, tumor markers, proteinogram, and cervical-thoraco-abdominal CT) were negative. The percutaneous puncture with fine needle of the tumor was inconclusive for the diagnosis; only blood fragments were obtained. Finally, it was decided to surgically intervene the patient based on the clinical progression of the lesion, with its esthetic implications, as well as to obtain a definitive histological diagnosis. During the surgery, a bone-dependent tumor was identified, with multiple dilated vascular channels in its center, which expanded the external table. To avoid manipulation of the lesion, it was decided to include it in a piece of craniectomy with a circumferential margin of 1 cm of the seemingly healthy bone. The resulting bone defect was reconstructed by means of a cylindrical metametacrylate plasty, which was fixed to the surrounding bone with titanium miniplates. The postoperative period was uneventful. The definitive anatomopathological diagnosis was intraosseous cavernous hemangioma.

Fig. 1
figure 1

Radiological images of a left frontal intraosseous lesion. a Simple X-ray of the skull, in the antero-posterior view and b in the lateral view of a radiolucent lesion (white arrows), rounded, with well-defined edges, located in the left frontal bone. c First CT cerebral with bone window performed on the patient 3 years ago. In localization of the left frontal region, a lytic bone lesion is observed that discreetly expands the diploe both in its internal and external table, with well-defined contours in its medullar region, being worse defined there could even be minimal solutions of continuity in the internal table. A poorly defined trabecular bone pattern was observed inside the lesion. The findings are compatible with a moderate aggressiveness. d In the last CT cerebral, it was appreciated how the lesion had increased in size. Produces a slight insufflation of the frontal calotte with loss of the cortex of the external table. Its behavior is of low radiological aggressiveness

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Discussion

The first case of cranial cavernous hemangioma was described by Toynbee in 1845 [54]. Since then, most of the publications in the scientific literature have been presented in a single clinical case format, with the exception of two reviews of extensive casuistry that constitute the main references on this entity [22]. PICHs of the skull are rare benign vascular tumors, accounting for about 0.2% of all tumors and 10% of benign tumors of the skull [59]. They occur most frequently in the spine and rarely in the skull. Of the 93 cases of cranial PICH reported in the literature from 1845 to 2015, 44.1% were located in the frontal bone, 12.9% in the temporal bone, 11.8% occurred in the occipital bone, 12, 9% in the parietal, and 5.4% in the cranial fossa; fewer cases have been reported in sphenoid, zygomatic, ethmoid, clivus, and orbital, etc. [37]. In the review carried out by Wyke, this distribution is supported [19].

They are usually unique lesions, although cases of multiple cranial cavernomas have been described [28]. They usually have a size at the time of diagnosis that ranges between 15 and 25 mm, although lesions of up to 8 cm diameter have been described [78]. Its origin is in the vessels of the diploic space, and their blood supplies are branches of the external carotid artery. The middle and superficial temporal arteries are the main sources of blood supply. Within the lesion, the capillaries are widely dilated and separated by fibrous tissue [77]. Its pathogenesis remains unknown. It was believed that it could be congenital, but this has not yet been proven. A previous trauma could also be an important etiology to consider [77]. The typical presentation is given by the presence of a hard, painless mass that slowly increases in size under an overlying intact skin. Sometimes they are associated with headache, which can be of high intensity when the hemangioma expands [79]. The most common clinical feature is a solid tumor in the skull, painful or painless.

The cranial CT with a bone window is the diagnostic modality of choice, since it surpasses the sensitivity of simple radiography and allows bone to be defined in a superior way to MRI, giving a detailed image of the cortical and trabecular bone. Although the appearance in the CT can vary, the characteristic image consists of a lytic lesion, oval or rounded, expansive, and well delimited, with trabeculae that radiate from a common center in its interior in the tangential cuts, giving sometimes an appearance of honeycombing in the axial cuts [21]. It frequently invades and expands the external table, respecting the periosteum. Usually no signs of reactive hyperostosis are identified at their margins [22]. The cortex can undergo a great expansion leaving a thin bone layer, but in almost all cases, the periosteum remains intact and usually without reactive sclerosis at the margins. The angiography of these lesions, typically the largest, demonstrates a hypervascular lesion, but without drainage veins. Preoperative embolization may be useful in some cases [80]. The differential diagnosis includes other slow-growing, expanding bone lesions, such as osteoma, aneurysmal bone cyst, giant cell tumor, and multiple myeloma [81]. The radiological characteristics that help the differential diagnosis are shown in Table 2.

Table 2 Differential diagnosis of skull vault lesions
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The natural history of these pathologies has not yet been described. Considering that osseous cavernous hemangiomas grow progressively, without spontaneous involution, their surgical treatment is usually recommended for several reasons: progression of the painful clinic, cosmetic implications, and, although with low frequency, avoidance of complications such as hemorrhages or nerve damage cranial, depending on the location of the lesion [22]. In 1923, Cushing designed the one that represents the treatment of choice of cranial cavernous hemangiomas to the present day: en bloc resection of the lesion, including a circumferential margin of the healthy bone [11]. On the other hand, the possibility of recurrence is avoided by including a margin of safety [77]. Most authors recommend total surgical excision to treat the mass effect and neurological compromise, to improve an esthetic deformity, and to obtain a definitive diagnosis [11]. The surgical approach becomes more difficult for those with extension to the base of the skull. Radiotherapy should be reserved for those lesions that are considered unresectable or in the case of recurrent tumors. This therapeutic modality stops tumor growth and reduces vascularization, but does not modify the size of the lesion and carries the risk of malignancy or the appearance of de novo malignancies [39].

Conclusions

Cranial cavernous hemangiomas are bony tumors of nature, which, in the absence of typical radiological features, are usually surgically treated under suspicion of another type of bone neoplasm. The treatment of choice is a complete resection by craniectomy, including healthy bone margins of safety, with good prognosis and little recurrence. In the presence of subtotal resections or progression, radiotherapy could be a valid option.