British Journal of Neurosurgery
ISSN: 0268-8697 (Print) 1360-046X (Online) Journal homepage: http://www.tandfonline.com/loi/ibjn20
Brain mushroom: A case of osteolytic intraosseous meningioma with transcalvaria herniation Sheng Chiong Hong, Kelvin Woon & Benjamin O'Keeffe To cite this article: Sheng Chiong Hong, Kelvin Woon & Benjamin O'Keeffe (2015): Brain mushroom: A case of osteolytic intraosseous meningioma with transcalvaria herniation, British Journal of Neurosurgery, DOI: 10.3109/02688697.2015.1029432 To link to this article: http://dx.doi.org/10.3109/02688697.2015.1029432
Published online: 20 Apr 2015.
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Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ibjn20 Download by: [University of Wisconsin Oshkosh]
Date: 06 November 2015, At: 10:29
British Journal of Neurosurgery, 2015; Early Online: 1–3 © 2015 The Neurosurgical Foundation ISSN: 0268-8697 print / ISSN 1360-046X online DOI: 10.3109/02688697.2015.1029432
SHORT REPORT
Brain mushroom: A case of osteolytic intraosseous meningioma with transcalvaria herniation Sheng Chiong Hong, Kelvin Woon & Benjamin O’Keeffe
Downloaded by [University of Wisconsin Oshkosh] at 10:29 06 November 2015
Department of Neurosurgery, Wellington Hospital, Wellington, New Zealand
complaints which lasted for about 20–30 s. He also described intermittent headaches which got worse over time. Neurological examination was normal and there were no obvious skull defects. The patient also has a history of asthma with chronic cough. His initial computerised tomography (CT) scan of head (Fig. 1) showed an osteolytic lesion on the left fronto-parietal region of the skull with no obvious intracranial pathology. This immediately raised the suspicion of bony metastasis but further haematological investigations have only reviewed findings consistent with monoclonal gammopathy of unknown significance (MGUS). This could not explain the development of a lytic lesion in his skull. Subsequent magnetic resonance imaging (MRI) scan of brain (Fig. 1) showed the remarkable feature of normal brain tissue within the osteolytic cavity of the skull consistent with transcalvaria herniation of the brain. Contrast study did not show any enhancement of the brain tissue within the cavity so a diagnosis of idiopathic transcalvaria herniation was made. A surgical repair of skull defect and brain hernia was performed and biopsies of the bony defect were performed (Fig. 2). A craniectomy removed the entire layers of bone surrounding the brain hernia. The skull opening was then closed with dural matrix and titanium mesh. The patient recovered uneventfully from the surgery. Histological study of the bony biopsies confirmed a WHO grade-1 invasive intraosseous meningioma. The rest of the underlying meningeal tissue were calcified but showed no histological evidence of meningioma. This further consolidated that the osteolytic meningioma was ectopic in origin. At 1-month follow-up the patient was well and was planned for MRI scan of brain at regular intervals.
Abstract A 61-year-old male presented with primary intraosseous osteolytic meningioma and transcalvaria herniation. This is an extremely rare condition with only 16 case reports of osteolytic intraosseous meningioma. This case is unique because it was accompanied by a transcalvaria herniation. Keywords: intraosseous osteolytic meningioma; transcalvaria herniation
Introduction Transcalvaria herniation is defined as ‘herniation of brain tissue through a defect in the skull’. Usual causes of transcalvaria herniation include post-traumatic skull fracture, congenital skull defect and post-surgical decompression or craniotomy. To our knowledge, there has never been a case report of transcalvaria herniation into a cavity created by an osteolytic intraosseous meningioma. Meningioma is usually considered as a benign tumour that arises from the arachnoid cap cells of the arachnoid layer of the meninges. In rare instances the meningioma occurs outside this layer and is called ‘an ectopic meningioma’. Ectopic meningiomas account for less than 1% of all meningiomas. In 2007, a literature review conducted by Al-Khawaja et al. revealed that there were only 66 reported cases of ectopic calvarial meningiomas.1 In view of the rarity of this condition, we present a case of intraosseous meningioma with transcalvaria herniation.
Case report
Discussion
A 61-year-old male presented with a 1-month history of stroke-like symptoms. He described weakness and numbness beginning in the right upper limb as his main
The majority of patients with meningioma are usually asymptomatic. Those who become symptomatic are a result
Correspondence: Dr. Sheng Chiong Hong, MB BCh BAO, PGDipOphthBS, Department of Neurosurgery, Wellington Hospital, Riddiford Street, Wellington 6021, New Zealand. E-mail: [email protected] Received for publication 15 November 2014; accepted 8 March 2015
1
Downloaded by [University of Wisconsin Oshkosh] at 10:29 06 November 2015
2 S. C. Hong et al.
Fig. 1. (A) MRI of brain T2 axial view. (B) MRI of brain T1 axial view. Both slides show normal brain tissue within the lytic cavity of the left frontoparietal region of the skull. (C) Axial CT scan of head with bone window. (D) Axial CT scan of head brain window without contrast. The CT scan revealed a lytic lesion on the left fronto-parietal region of the skull with an opening into the intracranial cavity.
Fig. 2. (A) A thin layer of discoloured skull bone overlying the lytic lesion. (B) Burr hole was created and the surrounding bone was slowly removed to expose the underlying brain tissue. (C) ‘Brain Mushroom’. The herniated brain tissue within the lytic bony cavity appears to be slightly infarcted. (D) The dural surrounding the neck of the hernia was removed to reduce the hernia.
Downloaded by [University of Wisconsin Oshkosh] at 10:29 06 November 2015
Brain mushroom 3 of mass effect caused by the tumour or the surrounding oedema causing raised intracranial pressure. As discussed before, ectopic calvarial meningiomas are rare; it is even rarer to see osteolytic intraosseous meningioma. Rosahl (2004) calculated that there were only 16 case reports.2 The aetiology of intraosseous meningioma has not been fully established, but some hypotheses have been proposed. For patients with congenital intraosseous meningioma, it is thought that part of the dura with the arachnoid cap cells might be trapped in the suture during delivery or moulding of the skull and subsequently develop into a meningioma. However, in those with history of head trauma, the arachnoid cap cells can be caught in the fracture line and when the fracture heals, these cells are trapped within the bone, thus acting as a source for future intraosseous meningioma. A patient with intraosseous meningioma unfortunately does not share the same prognosis of a patient with a common intracranial meningioma of the same WHO grade. Besides having a higher rate of atypical or malignant features, these intraosseous meningiomas tend to recur more frequently. Recurrence of atypical or malignant intraosseous meningiomas has been reported to recur up to 2 years after surgical resection, whereas histologically benign tumours have been reported to recur up to 10 years after surgery.3 It is therefore justifiable to follow up this group of patients with scans taken at regular intervals. This case also demonstrates the rare and unique presentation of a transcalvaria herniation. Transcalvaria herniations are often present iatrogenically from surgical procedures that help to decrease intracranial pressure in intracranial bleeds and/or oedema in trauma scenarios. Our patient had neither of these. The osteolytic meningioma could have created
a defect in the skull at the first place. Our patient’s chronic cough episodes could have caused intermittently increased intracranial pressure and therefore exacerbated this defect allowing herniation to occur into the lytic lesion. The fact that the diagnosis of an ectopic meningioma was not made pre-operatively was interesting. The meningioma was not visible macroscopically on radiological scans and even during surgery. One plausible explanation is that the tumour could have regressed as a consequence of cerebral herniation. Regression of meningiomas has been reported after haemorrhage, hormonal withdrawal and rarely spontaneously.4 However, there has not been a case of ectopic meningioma regression accompanied by an underlying cerebral herniation. The mechanism could possibility warrant future investigations on the subject of ‘Pressure induced meningioma regression’. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
References 1. Al-Khawaja D, Murali R, Sindler P. Primary calvarial meningioma. J Clin Neurosci 2007;14:1235–39. 2. Rosahl SK, Mirzayan MJ, Samii M. Osteolytic intra-osseous meningiomas: illustrated review. Acta Neurochir 2004;146:1245–49. 3. Lang FF, Macdonald OK, Fuller GN, DeMonte F. Primary extradural meningiomas: A report on nine cases and review of the literature from the era of computerized tomography scanning. J Neurosurg 2000;93:940–50. 4. Hirota K, Fujita T, Akagawa H, Onda H, Kasuya H. Spontaneous regression together with increased calcification of incidental meningioma. Surg Neurol Int 2014;5:73.
ISSN: 0268-8697 (Print) 1360-046X (Online) Journal homepage: http://www.tandfonline.com/loi/ibjn20
Brain mushroom: A case of osteolytic intraosseous meningioma with transcalvaria herniation Sheng Chiong Hong, Kelvin Woon & Benjamin O'Keeffe To cite this article: Sheng Chiong Hong, Kelvin Woon & Benjamin O'Keeffe (2015): Brain mushroom: A case of osteolytic intraosseous meningioma with transcalvaria herniation, British Journal of Neurosurgery, DOI: 10.3109/02688697.2015.1029432 To link to this article: http://dx.doi.org/10.3109/02688697.2015.1029432
Published online: 20 Apr 2015.
Submit your article to this journal
Article views: 29
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ibjn20 Download by: [University of Wisconsin Oshkosh]
Date: 06 November 2015, At: 10:29
British Journal of Neurosurgery, 2015; Early Online: 1–3 © 2015 The Neurosurgical Foundation ISSN: 0268-8697 print / ISSN 1360-046X online DOI: 10.3109/02688697.2015.1029432
SHORT REPORT
Brain mushroom: A case of osteolytic intraosseous meningioma with transcalvaria herniation Sheng Chiong Hong, Kelvin Woon & Benjamin O’Keeffe
Downloaded by [University of Wisconsin Oshkosh] at 10:29 06 November 2015
Department of Neurosurgery, Wellington Hospital, Wellington, New Zealand
complaints which lasted for about 20–30 s. He also described intermittent headaches which got worse over time. Neurological examination was normal and there were no obvious skull defects. The patient also has a history of asthma with chronic cough. His initial computerised tomography (CT) scan of head (Fig. 1) showed an osteolytic lesion on the left fronto-parietal region of the skull with no obvious intracranial pathology. This immediately raised the suspicion of bony metastasis but further haematological investigations have only reviewed findings consistent with monoclonal gammopathy of unknown significance (MGUS). This could not explain the development of a lytic lesion in his skull. Subsequent magnetic resonance imaging (MRI) scan of brain (Fig. 1) showed the remarkable feature of normal brain tissue within the osteolytic cavity of the skull consistent with transcalvaria herniation of the brain. Contrast study did not show any enhancement of the brain tissue within the cavity so a diagnosis of idiopathic transcalvaria herniation was made. A surgical repair of skull defect and brain hernia was performed and biopsies of the bony defect were performed (Fig. 2). A craniectomy removed the entire layers of bone surrounding the brain hernia. The skull opening was then closed with dural matrix and titanium mesh. The patient recovered uneventfully from the surgery. Histological study of the bony biopsies confirmed a WHO grade-1 invasive intraosseous meningioma. The rest of the underlying meningeal tissue were calcified but showed no histological evidence of meningioma. This further consolidated that the osteolytic meningioma was ectopic in origin. At 1-month follow-up the patient was well and was planned for MRI scan of brain at regular intervals.
Abstract A 61-year-old male presented with primary intraosseous osteolytic meningioma and transcalvaria herniation. This is an extremely rare condition with only 16 case reports of osteolytic intraosseous meningioma. This case is unique because it was accompanied by a transcalvaria herniation. Keywords: intraosseous osteolytic meningioma; transcalvaria herniation
Introduction Transcalvaria herniation is defined as ‘herniation of brain tissue through a defect in the skull’. Usual causes of transcalvaria herniation include post-traumatic skull fracture, congenital skull defect and post-surgical decompression or craniotomy. To our knowledge, there has never been a case report of transcalvaria herniation into a cavity created by an osteolytic intraosseous meningioma. Meningioma is usually considered as a benign tumour that arises from the arachnoid cap cells of the arachnoid layer of the meninges. In rare instances the meningioma occurs outside this layer and is called ‘an ectopic meningioma’. Ectopic meningiomas account for less than 1% of all meningiomas. In 2007, a literature review conducted by Al-Khawaja et al. revealed that there were only 66 reported cases of ectopic calvarial meningiomas.1 In view of the rarity of this condition, we present a case of intraosseous meningioma with transcalvaria herniation.
Case report
Discussion
A 61-year-old male presented with a 1-month history of stroke-like symptoms. He described weakness and numbness beginning in the right upper limb as his main
The majority of patients with meningioma are usually asymptomatic. Those who become symptomatic are a result
Correspondence: Dr. Sheng Chiong Hong, MB BCh BAO, PGDipOphthBS, Department of Neurosurgery, Wellington Hospital, Riddiford Street, Wellington 6021, New Zealand. E-mail: [email protected] Received for publication 15 November 2014; accepted 8 March 2015
1
Downloaded by [University of Wisconsin Oshkosh] at 10:29 06 November 2015
2 S. C. Hong et al.
Fig. 1. (A) MRI of brain T2 axial view. (B) MRI of brain T1 axial view. Both slides show normal brain tissue within the lytic cavity of the left frontoparietal region of the skull. (C) Axial CT scan of head with bone window. (D) Axial CT scan of head brain window without contrast. The CT scan revealed a lytic lesion on the left fronto-parietal region of the skull with an opening into the intracranial cavity.
Fig. 2. (A) A thin layer of discoloured skull bone overlying the lytic lesion. (B) Burr hole was created and the surrounding bone was slowly removed to expose the underlying brain tissue. (C) ‘Brain Mushroom’. The herniated brain tissue within the lytic bony cavity appears to be slightly infarcted. (D) The dural surrounding the neck of the hernia was removed to reduce the hernia.
Downloaded by [University of Wisconsin Oshkosh] at 10:29 06 November 2015
Brain mushroom 3 of mass effect caused by the tumour or the surrounding oedema causing raised intracranial pressure. As discussed before, ectopic calvarial meningiomas are rare; it is even rarer to see osteolytic intraosseous meningioma. Rosahl (2004) calculated that there were only 16 case reports.2 The aetiology of intraosseous meningioma has not been fully established, but some hypotheses have been proposed. For patients with congenital intraosseous meningioma, it is thought that part of the dura with the arachnoid cap cells might be trapped in the suture during delivery or moulding of the skull and subsequently develop into a meningioma. However, in those with history of head trauma, the arachnoid cap cells can be caught in the fracture line and when the fracture heals, these cells are trapped within the bone, thus acting as a source for future intraosseous meningioma. A patient with intraosseous meningioma unfortunately does not share the same prognosis of a patient with a common intracranial meningioma of the same WHO grade. Besides having a higher rate of atypical or malignant features, these intraosseous meningiomas tend to recur more frequently. Recurrence of atypical or malignant intraosseous meningiomas has been reported to recur up to 2 years after surgical resection, whereas histologically benign tumours have been reported to recur up to 10 years after surgery.3 It is therefore justifiable to follow up this group of patients with scans taken at regular intervals. This case also demonstrates the rare and unique presentation of a transcalvaria herniation. Transcalvaria herniations are often present iatrogenically from surgical procedures that help to decrease intracranial pressure in intracranial bleeds and/or oedema in trauma scenarios. Our patient had neither of these. The osteolytic meningioma could have created
a defect in the skull at the first place. Our patient’s chronic cough episodes could have caused intermittently increased intracranial pressure and therefore exacerbated this defect allowing herniation to occur into the lytic lesion. The fact that the diagnosis of an ectopic meningioma was not made pre-operatively was interesting. The meningioma was not visible macroscopically on radiological scans and even during surgery. One plausible explanation is that the tumour could have regressed as a consequence of cerebral herniation. Regression of meningiomas has been reported after haemorrhage, hormonal withdrawal and rarely spontaneously.4 However, there has not been a case of ectopic meningioma regression accompanied by an underlying cerebral herniation. The mechanism could possibility warrant future investigations on the subject of ‘Pressure induced meningioma regression’. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
References 1. Al-Khawaja D, Murali R, Sindler P. Primary calvarial meningioma. J Clin Neurosci 2007;14:1235–39. 2. Rosahl SK, Mirzayan MJ, Samii M. Osteolytic intra-osseous meningiomas: illustrated review. Acta Neurochir 2004;146:1245–49. 3. Lang FF, Macdonald OK, Fuller GN, DeMonte F. Primary extradural meningiomas: A report on nine cases and review of the literature from the era of computerized tomography scanning. J Neurosurg 2000;93:940–50. 4. Hirota K, Fujita T, Akagawa H, Onda H, Kasuya H. Spontaneous regression together with increased calcification of incidental meningioma. Surg Neurol Int 2014;5:73.
![[Primary osteolytic intraosseous meningioma of the occipital bone].](/assets/img/hold.png)
