Open Access

Solitary intracranial osteoma with attachment to the falx: a case report

  • Shu-Mei Chen1, 2,
  • Chi-Cheng Chuang3,
  • Cheng-Hong Toh4,
  • Shih-Ming Jung5 and
  • Tai-Ngar Lui1Email author
World Journal of Surgical Oncology201311:221

https://doi.org/10.1186/1477-7819-11-221

Received: 17 October 2012

Accepted: 28 August 2013

Published: 8 September 2013

Abstract

Background

Intracranial osteomas are uncommon lesions that usually arise from the inner table of the cranium. There are few reports in the literature of intracranial osteomas with meninges attachment and without direct relation with the skull bone; these osteomas were mostly attached with dura. We report a rare osteoma with falx attachment.

Case

A 64-year-old woman presented with a 3-month history of intermittent tinnitus and dizziness. The scout film of petrous bone computed tomography scan revealed a high-density lesion in the frontal area. Magnetic resonance imaging showed a 2.5-cm mass attached to the surface of the falx in the right frontal parasagittal area. The patient underwent right frontal craniotomy, and a bony hard mass was found located in the right frontal parasagittal region extra-axially, with its medial surface attached to the falx. It could not be broken down by the cavitron ultrasonic surgical aspirator or even the cutting loop and was detached from the falx and removed in one piece. Histopathological examination showed a nodule with bony trabeculae and bone marrow tissue, compatible with osteoma. The postoperative course was uneventful, and the patient was discharged from the hospital with no neurological deficits one week after operation.

Conclusions

This is the first case report in the English literature of an intracranial osteoma arising from the falx. Because of their slow growth and their locations in silent brain areas, intracranial osteomas are usually diagnosed incidentally. Surgical resection is the primary treatment choice.

Keywords

FalxIntracranialOsteoma

Background

Osteomas are benign neoplasms consisting of mature normal osseous tissue. They commonly arise from the long bones of the extremities. In the head and neck region, they are usually found in the sinuses, facial bones, skull, and mandible [19]. Intracranial osteomas are rarely located intradurally without the involvement of bony structure [10]. The mechanism that triggers the formation of intracranial intradural osteomas without bony structure involvement remains unclear. We report the clinical presentation, pathologic picture, and intra-operative findings of an intradural osteoma with attachment to the falx.

Case presentation

A 64-year-old woman presented with a 3-month history of intermittent bilateral tinnitus, occasionally accompanied by dizziness. She had no history of major head injury or systemic infection. She visited an otology clinic where a temporal bone computed tomography (CT) scan of the petrous bone, semicircular canal, and hearing apparatus showed neither temporal bone lesions nor associated lesions in the ear; however, the scout film of the CT scan incidentally revealed a radiopaque nodule in the frontal area (Figure 1). Magnetic resonance imaging (MRI) revealed a 2.5-cm mass with minimal marginal enhancement in the right parasagittal region in axial and coronal contrast-enhanced T1-weighted images. The mass was hyperintense with a hypointense rim in T2-weighted images (Figure 2). The provisional diagnosis was a calcified meningioma originating from the falx. The patient was then referred to our neurosurgical department for surgical removal of the tumor. On admission, the physical and neurological findings were unremarkable. Her cognitive function was intact, and she had no sensorimotor deficit. Right frontal craniotomy was performed. After opening of the dura and retraction of the parasagittal gyri, a tumor was found attached to the falx in the mesial frontal lobe extra-axially. The tumor was as hard as bone and could not be broken by bipolar forceps, Cavitron ultrasonic surgical aspirators, or even cutting loops. The tumor had to be dissected apart from the falx surface in one piece (Figure 3).
Figure 1

Scout film of the petrous bone computed tomography (CT) scan. It showed a dense radiopaque mass in the frontal area.

Figure 2

Magnetic resonance imaging (MRI). Axial and coronal contrast-enhanced T1-weighted images with fat saturation show a 2.5-cm falx-based mass with minimal marginal enhancement in the right parasagittal region. The mass is hyperintense with a hypointense rim on T2-weighted images.

Figure 3

Gross appearance of the osteoma. The medial surface (arrow) was attached on the falx.

Pathologic examination revealed lamellated bony trabeculae lined by osteoblasts, and the intertrabecular marrow spaces were occupied by loose fibrovascular tissue (Figure 4).
Figure 4

Histopathology of the resected specimen. Lamellated bony trabeculae and the intertrabecular space occupied by loose fibrovascular tissue as observed during pathological examination (original magnification × 20).

The postoperative course was uneventful. The patient was discharged from the hospital with no neurological deficits after suture removal. During six months of post-operative follow-up, the frequency and degree of dizziness and tinnitus decreased progressively.

Discussion

Osteomas are recognized as benign bone neoplasms of uncertain etiology. In the head, osteomas often arise from the periosteum of the frontal or ethmoid sinuses and the mandible [19]. Less often, osteomas may originate from the cranial bone in the convexity or the inner layer of the dura mater [1114]. Osteomas attached to the meninges without relationship with the bone are even rarer. We reviewed related literature and summarized the data (Table 1). Fallon et al. [15] found intracranial meningeal osteomas in 5% of 200 adult autopsies. The tumors were usually located at the convexity dura and falx junction around the superior sagittal sinus. Solitary intracranial osteomas arising from the inner layer of the dura mater with no involvement of the cranium have been reported [11, 12, 14, 1618]. The tumors usually establish themselves with a wide base and grow inward as an expanding mass with a well-defined border [12]. The osteoma we report on here was a fungating nodule with a narrow neck attached to the falx.
Table 1

Patients with intracranial osteoma attached to the meninges without relationship with the bone reported in the literature

No.

Age/Sex

Preoperative symptom

Location

Size

Surgery

Operative finding

Postoperative outcome

(ref.)

1

20/F

Headache over right fronto-temporal area

Right frontal convexity

1.0 x 1.0 x 1.0 cm3

Right fronto-temporal craniotomy

Arose from the inner surface of dura

Asymptomatic

[12]

2

51/F

Headache

Right frontal convexity

1.1 x 1.5 x 0.7 cm3

Right frontal craniotomy

Partially adherent to the inner dural surface

No post-operative problem

[16]

3

28/F

Headache at left frontal area

Left frontal convexity

4.0 x 2.5 x 0.5 cm3

Left frontal craniotomy

Covered with arachnoid membrane

Relief of headache

[10]

4

35/M

Vertigo

Right frontal convexity

5.0 x 5.0 x 2.0 cm3

Right frontal craniotomy

Attached to the dura

Not available

[14]

5

24/M

Headache

Right frontal convexity

Not available*

Right frontal craniotomy

Covered with arachnoid membrane

Venous congestion post-operative 3 days

[18]

No sign of recurrence 2 years after the surgery

6

60/M

Headache

Right frontal convexity

Not available

Right frontal craniotomy

Attached to the dura

No neurologic deficits

[17]

7

43/F

Headache in left frontal area

Left frontal convexity

1.2 x 2.0 x 0.7 cm3

Left frontal craniotomy

Attached to the dura

Asymptomatic

[11]

8

64/M

Tinnitus with dizziness

Right mesial frontal lobe extra-axially

2.5 x 2.0 x 2.0 cm3

Right frontal craniotomy

Attached to the falx

The frequency and degree of dizziness and tinnitus decreased

Present case

* multiple.

On the basis of their natural history, intracranial osteomas are more benign than osteomas of the frontal sinuses [19]. The tumor may cause pressure-related symptoms by compressing or displacing the underlying brain, and this depends on the location of the mass. When it appears in a silent area, it rarely causes sensorimotor deficit. Most commonly, such tumors are detected in patients presenting with headache or other non-specific complaints. The high frequency of head trauma history has been noted, and the possible importance of head trauma as a causative factor in cranial osteomas has been proposed [17, 20]. In our case, there was no history of major head trauma. This intracranial osteoma was found incidentally on the scout image during a temporal bone CT scan.

The pathogenesis of osteomas without bone involvement is still unknown. A dural osteoma can be confused with “meningeal ossification or meningeal calcification” originating from the dura or the falx because of the similarities in CT and MRI examinations and microscopic appearance [15]. This new bone might not represent a true neoplasm but possibly an osteogenic change in the cerebral meningeal tissue. However, meningeal ossifications are commonly multicentric and located on the dural-falx junction along the both sides of the superior sagittal sinus [21].

The factors leading to the genesis of intracranial meningeal osteomas are as yet unknown. New bone formation from the dura or falx has been postulated as one of the causes because the meninges may function as the periosteum of the inner table of the skull [10, 12, 15].

Conclusions

In our patient, the operative findings confirmed an intracranial bony hard mass arising from the falx. This intradural osteoma might have been the result of a focal falx osteogenic activity. To the best of our knowledge, this is the first report of an intracranial osteoma that originated from the falx in an otherwise normal patient.

Consent

The patient consented to the study and publication of this case report and images. A written consent is available for review.

Abbreviations

CT: 

Computed tomography

MRI: 

Magnetic resonance imaging.

Declarations

Authors’ Affiliations

(1)
Department of Neurosurgery, Taipei Medical University-Wan Fang Hospital, Taipei Medical University
(2)
Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University
(3)
Department of Neurosurgery, Chang Gung Memorial Hospital at Linkou, Chang Gung University
(4)
Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital at Linkou, Chang Gung University
(5)
Department of Pathology, Chang Gung Memorial Hospital at Linkou, Chang Gung University

References

  1. Armitage G: Osteoma of the frontal sinus: with particular reference to its intracranial complications and with report of a case. Br J Surg. 1931, 18: 565-580. 10.1002/bjs.1800187205.View ArticleGoogle Scholar
  2. Bingas B: Tumours of the base of the skull. Handbook of Clinical Neurology. Edited by: Vinken PJ, Bruyn GW. 1974, New York, Amsterdam: Elsevier Publishing Co., Inc, 136-233.Google Scholar
  3. Campbell EH, Gottschalk RB, Albany AB: Osteoma of frontal sinus and penetration of lateral ventricle with intermittent pneumocephalus. JAMA. 1938, 111: 239-241. 10.1001/jama.1938.72790290001007.View ArticleGoogle Scholar
  4. Diaz F, Latchow R, Duvall AJ, Quick CA, Erickson DL: Mucoceles with intracranial and extracranial extensions. J Neurosurg. 1978, 48: 284-288. 10.3171/jns.1978.48.2.0284.View ArticlePubMedGoogle Scholar
  5. Suen JY, Meyers EH: Cancer of the Head and Neck. 1981, New York: Churchill, LivingstoneGoogle Scholar
  6. Lunardi P, Missori P, Di Lorenzo N, Fortuna A: Giant intracranial mucocele secondary to osteoma of the frontal sinuses: report of two cases and review of the literature. Surg Neurol. 1993, 39: 46-48. 10.1016/0090-3019(93)90109-E.View ArticlePubMedGoogle Scholar
  7. Pool JL, Potanos JN, Keueger EG: Osteomas and mucocele of the frontal paranasal sinuses. J Neurosurg. 1962, 19: 130-135. 10.3171/jns.1962.19.2.0130.View ArticlePubMedGoogle Scholar
  8. Russell DS, Rubinstein LJ: Pathology of Tumours of the Nervous System. 1989, London: Edward ArnoldGoogle Scholar
  9. Spjut HJ, Dorfman HD, Fechner RE, Ackerman LV: Tumours of Bone and Cartilage. 1971, Washington DC: Armed Forces Institute of PathologyGoogle Scholar
  10. Lee ST, Lui TN: Intracerebral osteoma: case report. Br J Neurosurg. 1997, 11: 250-252. 10.1080/02688699746357.View ArticlePubMedGoogle Scholar
  11. Cheon JE, Kim JE, Yang HJ: CT and pathologic findings of a case of subdural osteoma. Korean J Radiol. 2002, 3: 211-223. 10.3348/kjr.2002.3.3.211.PubMed CentralView ArticlePubMedGoogle Scholar
  12. Choudhury AR, Haleem A, Jjan GT: Solitary intradural intracranial osteoma. Brit J Neurosurg. 1995, 9: 557-559. 10.1080/02688699550041232.View ArticleGoogle Scholar
  13. Rand CW: Osteoma of the skull. Report of two cases, one being associated with a large intracranial endothelioma. Arch Surg Chicago. 1923, 6: 573-586. 10.1001/archsurg.1923.01110180146005.View ArticleGoogle Scholar
  14. Sugimoto K, Nakahara I, Nishikawa M, Tanaka M, Terashima T, Yanagihara H, Hayashi J: Osteoma originating in the dura: a case report. No Shinkei Geka. 2001, 29: 993-996. [In Japanese]PubMedGoogle Scholar
  15. Fallon MD, Ellerbrake D, Teitelbaum SL: Meningeal osteomas and chronic renal failure. Hum Pathol. 1982, 13: 449-453. 10.1016/S0046-8177(82)80027-0.View ArticlePubMedGoogle Scholar
  16. Aoki H, Nakase H, Sakaki T: Subdural osteoma. Acta Neurochir. 1998, 140: 727-728. 10.1007/s007010050171.View ArticlePubMedGoogle Scholar
  17. Dukes HT, Odom GL: Discrete intradural osteoma. Report of a case. J Neurosurg. 1962, 19: 251-253. 10.3171/jns.1962.19.3.0251.View ArticlePubMedGoogle Scholar
  18. Akiyama M, Tanaka T, Hasegawa Y, Chiba S, Abe T: Multiple intracranial subarachnoid osteomas. Acta Neurochir. 2005, 147: 1085-1089. 10.1007/s00701-005-0588-1.View ArticlePubMedGoogle Scholar
  19. Vaket A, Reuck JD, Thiery E, Eecken HV: Intracerebral osteoma: a clinicopathologic and neuropsychologic case study. Childs Brain. 1983, 10: 281-285.Google Scholar
  20. Cushing H: Experiences with orbito-ethmoidal osteomata having intracranial complications. With the report of four cases. Surg Gynecol Obstet. 1927, 44: 721-742.Google Scholar
  21. Jung TY, Jung S, Jin SG, Jin YH, Kim IY, Kang SS: Solitary intracranial subdural osteoma: intraoperative findings and primary anastomosis of an involved cortical vein. J Clin Neurosci. 2007, 14: 468-470. 10.1016/j.jocn.2005.11.021.View ArticlePubMedGoogle Scholar

Copyright

© Chen et al.; licensee BioMed Central Ltd. 2013

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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