Novel Insights from Clinical Practice Pediatr Neurosurg 2016;51:83–86 DOI: 10.1159/000441008 Received: July 29, 2015 Accepted: September 10, 2015 Published online: November 3, 2015 Pediatric Intraparenchymal Meningioma: Case Report and Comparative Review Thomas Larrew Ramin Eskandari Department of Neurosurgery, Medical University of South Carolina, Charleston, S.C., USA Established Facts • Pediatric meningiomas are considerably rarer than their adult counterparts. • Despite atypical imaging or gross findings of an intracranial tumor, a definitive diagnosis is made with histological examination. Novel Insights • This report describes some of the unusual features pediatric meningiomas can have, such as an intraparenchymal nature and a tissue composition with two distinct qualities. • The lack of dural adherence does not completely rule out a meningioma and should be considered on the differential with cystic, calcified tumors. Abstract Intra-axial (intraparenchymal) meningiomas are an extremely rare pathology with only dozens of cases reported. In children, the unusual characteristics of intraparenchymal meningiomas can easily create an atypical preoperative differential. The authors present the case of an otherwise healthy 14-year-old girl presenting with new-onset seizures and an intracranial lesion upon investigation. CT and MRI revealed a lesion both cystic and calcified in nature, residing completely within the brain parenchyma. Upon operative examination, the mass was found to be completely surrounded by © 2015 S. Karger AG, Basel 1016–2291/15/0512–0083$39.50/0 E-Mail karger@karger.com www.karger.com/pne cortex and to be of two disparate consistencies. Pathological analysis revealed the mass to be a meningioma. Despite the rarity in children, meningiomas must be kept on the differential for cystic, calcified lesions. The differential diagnosis based on imaging as well as the operative strategy taken are further discussed. In addition, the authors review the current understanding of pediatric meningiomas as compared with adult meningiomas. © 2015 S. Karger AG, Basel Introduction Meningiomas represent a significant burden of disease among neurosurgical tumors, comprising approximately one third of all central nervous system (CNS) tumors in Ramin Eskandari Department of Neurosurgery, Medical University of South Carolina 96 Jonathan Lucas St., Ste. 301CSB Charleston, SC 29425 (USA) E-Mail eskandar @ musc.edu Downloaded by: University of Illinois at Chicago 128.248.155.225 - 11/7/2016 7:06:05 AM Key Words Meningioma · Intra-axial meningioma · Intraparenchymal meningioma · Oncology the general population [1, 2]. In the pediatric age group, this type of tumor is considerably rarer, making up roughly 2% of all pediatric CNS tumors [1, 3]. A variant of the pediatric meningioma that is even more uncommon is that found to be completely intra-axial (intraparenchymal) and to arise without dural attachments. Here, we highlight the case of a young girl with an intraparenchymal meningioma along with the operative challenges of this type of tumor. We present information from a review of the literature demonstrating the rarity of not only the tumor location, but also the demographic age of the patient in which it presented. Also highlighted is a systemic distinction of pediatric meningiomas from their adult counterparts. a c b d Case Report Imaging Head computer tomography (CT) revealed a left frontal mass with surrounding vasogenic edema, brain compression and calcifications (fig. 1b). Further magnetic resonance imaging (MRI) demonstrated an intra-axial lesion 4.1 × 3.7 × 5.3 cm in size (anteroposterior by lateral by craniocaudal) in close proximity to Broca’s area without a clear dural tail (fig. 1a). The intratumoral pockets of hypointensity suggested cystic degeneration changes. Significant vasogenic edema caused a mass effect and a 10-mm rightward subfalcine shift as well as compression of the frontal horn of the left lateral ventricle. Treatment and Postoperative Course The primary goal of treatment in this case was surgical resection and tissue diagnosis. The patient was taken for MRI-guided stereotactic left frontal craniotomy. Dexamethasone was given perioperatively to decrease cerebral edema. A curvilinear pterional incision was made short of the zygomatic arch, and a myocutaneous flap was reflected. Using MRI-guided navigation, a 84 Pediatr Neurosurg 2016;51:83–86 DOI: 10.1159/000441008 Fig. 1. Preoperative imaging. a Axial T2-weighted FLAIR. b Axial CT without contrast demonstrating calcified left frontal mass. c Sagittal T1-weighted postgadolinium image demonstrating a 4.1 × 3.7 × 5.3 cm frontal mass. d Axial T1-weighted image with contrast. craniotomy flap was lifted and the dura incised in a cruciate fashion. Under the neurosurgical microscope, the overlying cortex immediately below the dura was grossly abnormal. There were no dural attachments upon reflecting the dura outward. The abnormal cortex was approximately 5 mm thick and covering the surface of the hard calcified tumor. This cortical layer was resected and sent as a separate pathology specimen. An intraoperative frozen section revealed abnormal tissue; however, final pathology of this region revealed gliosis and reactive cortex without evidence of tumor pathology. The large, superior and more superficial calcified mass was adherent to the surrounding brain. The surrounding cortex was retracted from the tumor circumferentially with coagulation and division of direct feeding pial vasculature, which the tumor had parasitized from the surrounding brain. The tumor was resected in two stages with the superficial fully calcified portion, which could not be debulked or incised, being taken first. Next, the deeper portion of the tumor was removed in piecemeal fashion. This was of different characteristic, not as calcified, but extremely hard, rubbery and fibrous. Postoperatively, the patient had no evidence of expressive aphasia, deficits in speech, detectable personality changes or motor/sensory deficits. Postoperative imaging showed no evidence of residual tumor, hemorrhage or infarction. She was discharged on postoperative day 2. Larrew/Eskandari Downloaded by: University of Illinois at Chicago 128.248.155.225 - 11/7/2016 7:06:05 AM History and Physical Examination We describe a previously healthy 14-year-old female who presented to an emergency department with a new-onset generalized tonic-clonic seizure. At the time of presentation, she was not symptomatic. Review of systems was not suggestive of any recent changes within the past couple of months, including headaches, fatigue or changes in behavior. She was afebrile and without any aberrations in her vital signs. Her birth history was notable for uterine rupture in her mother at approximately 35 weeks gestational age followed by a 4-day neonatal intensive care stay without any subsequent complications. She did not have any medical conditions and prior to her presentation had been otherwise healthy. On physical examination, she was alert and oriented with bilateral and symmetric pupillary response and intact extraocular muscle movements. Cranial nerves were otherwise intact. Examination of her motor, sensory and cerebellar function was nonrevealing with benign findings. Laboratory workup revealed a normal basic metabolic panel and complete blood count except for a mild leukocytosis with 90% neutrophil predominance. b Fig. 2. Postoperative imaging. a Axial T2-weighted FLAIR. b Sagittal T1-weighted postgadolinium image. Pathology Fresh samples representative of the various components of the tumor were sent for pathological examination. The biopsy of the abnormal cortex beneath the dura, described as red and black in appearance, was given a final diagnosis of gliotic tissue. Biopsies from the two other sections of the tumor, the calcified portion and the very firm, deep component, were both found to be consistent with a World Health Organization (WHO) grade I meningioma. Follow-Up At the patient’s 3-month follow-up visit, she had a normal neurological examination, without any deficits or reemergence of her prior seizure. She was not taking any medications. MRI at this time revealed no evidence of residual tumor and demonstrated near complete resolution of edema (fig. 2). The patient will continue to have clinic visits with MRI starting at postoperative month 9 and thereafter on an annual basis. Discussion In the adult population, meningiomas make up a considerable proportion of CNS tumors at approximately 35% [1]. Meningiomas in the pediatric population differ in this regard, making up only 2.5% of all pediatric CNS tumors with an annual incidence of 0.13 per 100,000 in the USA [1]. These infrequent pediatric tumors have tissue characteristics and histological findings very distinct from their adult counterparts. There are also disparate epidemiological qualities between the two groups with less significant female preponderance within the pediatric population [1, 4]. Some studies attribute a similar incidence to both sexes, while others suggest a higher incidence among male children [1, 3, 5, 6]. The reason for this variation of incidence between pediatric and adult meningiomas is unknown but is perhaps suggestive of different pathophysiologies. Pediatric Intraparenchymal Meningioma Meningiomas, by definition, arise from meningothelial cells and so are primarily dura based [7]. However, there has been a small number of cases reported of meningiomas that were distinct from the dura [8–14]. These tumors create an unusual diagnostic picture, often appearing similar to other CNS tumors given their location and imaging characteristics. These highly vascular tumors can appear as heterogeneous masses, due to the potential presence of cystic changes and calcifications. In addition, they can invade pial boundaries and can cause significant cerebral edema appearing very aggressive on imaging. Moreover, in the pediatric population, these particular features are often suggestive of other, more common pediatric CNS tumors such as oligodendroglioma and ependymomas [15, 16]. Case reports have demonstrated such circumstances, with intra-axial meningiomas imitating pathologies like cavernous malformations and malignant gliomas [9, 13]. Tumor morphology significantly differs between pediatric and adult meningiomas. Cystic lesions have been described more commonly in children, with one study reporting cystic lesions in up to 15% of pediatric meningiomas compared to the <4% of adults [4, 17, 18]. While meningiomas in children are rare, it appears that they may be more commonly intraparenchymal than in adults, with more than half of reported cases of intraparenchymal meningiomas being pediatric [8, 17]. Definitive rates are difficult to determine based purely on case studies and secondary to an extremely low incidence. In adults, the two primary prognostic factors dictating progression-free survival for meningiomas are extent of tumor resection and histological grading [19, 20]. Data suggests that in the pediatric population the correlation between histological WHO grade and recurrence-free and overall survival is not as strong as in adults [21]. Meningioma subtypes differ substantially between the two age groups, with high-grade tumors more prevalent in the pediatric age group [22]. A single institution review of 51 cases found approximately 10% of pediatric meningiomas were histologically consistent with the papillary subtype, WHO grade III, compared with less than 1% among adult meningiomas [6]. A majority of the literature regarding pediatric meningiomas recapitulates information from case reports and small case series, which may contribute to often dissimilar conclusions in texts. Given the age of the patient in this case, MRI detection of heterogeneous enhancement, calcification, cystic lesions and presentation with new-onset seizure, a differential diagnosis of CNS lesions was oligodendroglioma, mixed oligoastrocytoma and ependymoma. Non-CNS lePediatr Neurosurg 2016;51:83–86 DOI: 10.1159/000441008 85 Downloaded by: University of Illinois at Chicago 128.248.155.225 - 11/7/2016 7:06:05 AM a sions were far less likely; however, a metastasis should always be considered with isolated lesions in a patient old enough to have other primary cancers. Although characteristics such as extremely large size, extensive calcifications and paucity of signs or symptoms in the patient were indicative of a low-grade, slowly growing lesion, the significant perilesional edema and mixed intensity/enhancement argued for possible malignant transformation. Intraoperative challenges for intraparenchymal meningiomas include the fibrous nature of most tumors making debulking arduous and dangerous. In this case, the tumor had two components, one dense and entirely calcified, which was superficial overlying the second more rubbery and less calcified portion deep within the parenchyma. Debulking of the superficial calcified component and collapsing the walls inward was not possible. Therefore, dissection of the cortex from around the tumor was required, ultimately having to roll the tumor within its cavity in order to completely free all parasitized vascular pedicles from the pia/parenchyma surrounding it. Ulti- mately, once the tumor was removed, an osteotome was required to split this component of the tumor into multiple parts. Although rare, meningiomas in children must be kept on the differential with cystic, calcified lesions. Without pathological examination, intra-axial meningiomas would undoubtedly be mistaken for other tumor types. This case reinforces that although imaging and physical appearance can be suggestive of a pathology, only a tissue biopsy can establish a diagnosis. Moreover, the lack of dural adherence does not completely rule out a meningioma. Although other, more common diagnoses should appear higher on the differential, intraparenchymal meningioma should remain on the list to allow for appropriate preparation for surgical resection. Disclosure Statement There was no funding for this project. There were no conflicts of interest involved. References 86 8 Karadereler S, Aker F, Berkman Z: Intraparenchymal meningioma in a child. Case report and review of the literature. J Neurosurg 2004;101:112–115. 9 Jadik S, Stan AC, Dietrich U, Pietilä TA, Elsharkawy AE: Intraparenchymal meningioma mimicking cavernous malformation: a case report and review of the literature. J Med Case Rep 2014;8:467. 10 Miranda P, Simal JA, Vila M, Hernández M, Menor F, Álvarez-Garijo JA: Posterior fossa clear cell meningioma without dural attachment in a child. Childs Nerv Syst 2009; 25: 389–392. 11 Mamourian C, Lewandowski E, Towfighi J: Cystic intraparenchymal meningioma in a child: case report. Am J Neuroradiol 1991;12: 366–367. 12 Chiocca EA, Boviatsis EJ, Westmark RM, Short MP, Richardson EP, Zervas NT: Deep Sylvian fissure meningioma without dural attachment in an adult: case report. Neurosurgery 1994;35:944–946; discussion 946. 13 Yamada SM, Fujimoto Y, Kawanishi Y, Shimizu K: A cystic meningioma misdiagnosed as malignant glioma by radiologic and intraoperative histological examinations. Brain Tumor Pathol 2010;27:111–115. 14 Shimbo D, Kato T, Takeda M, Ikeda H: Intraparenchymal meningioma in a child. Neurol Med Chir (Tokyo) 2011;51:793–797. Pediatr Neurosurg 2016;51:83–86 DOI: 10.1159/000441008 15 Tortori-Donati P, Rossi A, Biancheri R, Garré ML, Cama A: Brain tumors; in Tortori-Donati P, Rossi A (eds): Pediatric Neuroradiology. Berlin, Springer, 2005, pp 329–426. 16 Starshak RJ: Cystic meningiomas in children: a diagnostic challenge. Pediatr Radiol 1996; 26:711–714. 17 Caroli E, Russillo M, Ferrante L: Intracranial meningiomas in children: report of 27 new cases and critical analysis of 440 cases reported in the literature. J Child Neurol 2006; 21: 31–36. 18 Dell S, Ganti SR, Steinberger A, McMurtry J: Cystic meningiomas: a clinicoradiological study. J Neurosurg 1982;57:8–13. 19 Sekhar LN, Levine ZT, Sarma S: Grading of meningiomas. J Clin Neurosci 2001; 8(suppl 1):1–7. 20 Prayson RA: Pathology of meningiomas; in Lee JH (ed): Meningiomas: Diagnosis, Treatment, and Outcome. Berlin, Springer, 2009, pp 31–43. 21 Perry A, Dehner LP: Meningeal tumors of childhood and infancy. An update and literature review. Brain Pathol 2003;13:386–408. 22 Pejavar S, Daphne H-K: Rare tumors; in Gupta N, Banerjee A, Haas-Kogan D (eds): Pediatric CNS Tumors. Berlin, Springer, 2010, pp 205–222. Larrew/Eskandari Downloaded by: University of Illinois at Chicago 128.248.155.225 - 11/7/2016 7:06:05 AM 1 Ostrom QT, Gittleman H, Farah P, Ondracek A, Chen Y, Wolinsky Y, et al: CBTRUS statistical report: primary brain and central nervous system tumors diagnosed in the United States in 2006–2010. Neuro Oncol 2013; 15 (suppl 2):ii1–ii56. 2 Wiemels J, Wrensch M, Claus EB: Epidemiology and etiology of meningioma. J Neurooncol 2010;99:307–314. 3 Arivazhagan A, Devi BI, Kolluri SVR, Abraham RG, Sampath S, Chandramouli BA: Pediatric intracranial meningiomas – do they differ from their counterparts in adults? Pediatr Neurosurg 2008;44:43–48. 4 Ferrante L, Acqui M, Artico M, Mastronardi L, Rocchi G, Fortuna A: Cerebral meningiomas in children. Childs Nerv Syst 1989;5:83– 86. 5 Liu Y, Li F, Zhu S, Liu M, Wu C: Clinical features and treatment of meningiomas in children: report of 12 cases and literature review. Pediatr Neurosurg 2008;44:112–117. 6 Deen HG, Scheithauer BW, Ebersold MJ: Clinical and pathological study of meningiomas of the first two decades of life. J Neurosurg 1982;56:317–322. 7 Riemenschneider MJ, Perry A, Reifenberger G: Histological classification and molecular genetics of meningiomas. Lancet Neurol 2006;5:1045–1054.