Intracranial extracerebral neuroglial heterotopia with parapharyngeal extension: pre-natal and post-natal imaging findings

Abstract

ABSTRACT. We report an unusual case of intracranial extracerebral neuroglial heterotopia (IENH) presenting with parapharyngeal extension. Neuroglial heterotopias are rarely reported pre-natally and, to our knowledge, there are no reported cases presenting pre-natal imaging findings of IENH with parapharyngeal extension. Because pre-and post-natal imaging studies are essential to diagnose IENH and plan surgical treatment, radiologists should be familiar with this rare condition. Neuroglial heterotopias (NHs) are rare congenital lesions characterised by the presence of differentiated neuroectodermal tissue in locations where neuronal and glial cells do not typically occur [1]. These lesions usually involve the head and neck regions and are more commonly described in extracranial locations such as the nose and nasopharynx, oral cavity, oropharynx, palate, tongue, lips, scalp and orbit. Although intracranial extracerebral NH has been described more frequently with the increased availability of MRI, it remains a very rare condition [2].Intracranial extracerebral neuroglial heterotopias (IENHs) with parapharyngeal or oropharyngeal extension have been presented in a limited number of reports [2,3]. To our knowledge, pre-natal imaging findings of this uncommon combination have not been reported before. We report a case of IENH with parapharyngeal extension and describe its antenatal and post-natal imaging features. Case reportA 28-year-old pregnant female (gravida 3, para 2) was referred to our institution after an obstetric ultrasound examination at 25 weeks' gestation identified a foetal intracranial mass with extension to the left side of the neck. A repeat obstetric ultrasound performed in our department showed an osseous malformation in the left frontotemporal area of the cephalic pole resulting from a solid, round, predominantly hypoechoic intracranial mass (4.864.2 cm) with an anechoic area inside. This mass appeared to be contiguous with a predominantly cystic mass (6.765.9 cm) on the left side of the neck (Figure 1). A foetal MRI was performed at 27 weeks gestation; this showed a solid cystic mass lesion in the left anterolateral portion of the craniofacial region (Figure 2). Subsequent ultrasound evaluations showed that the mass had remained stable during pregnancy.The female infant was delivered pre-term by the ex utero intrapartum treatment procedure (EXIT) at 36 weeks gestation because of the risk of airway compression. Apgar scores at 1 min and 5 min were 9 and 10, respectively. The patient, who weighed 3045 g at birth, was admitted into the neonatal intensive care unit on mechanical ventilation. On clinical examination, the neonate had a large, soft, compressible cervical mass involving the frontotemporal region of the head.An MRI scan performed at the age of 1 day showed a large heterogeneous lesion with solid and cystic components. The solid component was an intracranial extracerebral lesion located in the left middle cranial fossa that presented a signal intensity similar to that of cerebral parenchyma...

Intracranial Extracerebral Glioneuronal Heterotopia with Adipose Tissue and a Glioependymal Cyst: A Case Report and Review of the Literature

“…Variably sized cysts in IEGH are not a rare finding, since they have been reported in 6 (31.6%) of the 19 cases ( Table 1 ). 1 , 2 , 4 , 5 , 8 , 9 Notably, 2 cysts were present in our case: one occupying the MCF and the other presenting around the tumor. Since, in our case, the glioependymal cyst was located inside the IEGH and some part of this cyst was surrounded by atrophic cerebellar tissue, the glioependymal cyst itself was thought be a main manifestation of the IEGH.…”

“…GH has been referred to as glioneuronal choristoma, glioneuronal hamartoma, brain heterotopia, and neuroglial heterotopia 1,4,5. It is a rare malformative lesion, and its precise incidence is unknown.…”

“…Although IEGH is a clinically and pathologically benign lesion, if it extends to extracranial areas or herniates into the skull base it can be harmful. IEGH can distort the anatomy of the skull base, and if it extends inferiorly into the infratemporal fossa, it can displace the upper airway and cause orbital dysplasia 5. In any case, surgical removal is the treatment of choice.…”

“…GH has been referred to as glioneuronal choristoma, glioneuronal hamartoma, brain heterotopia, and neuroglial heterotopia. 1 , 4 , 5 It is a rare malformative lesion, and its precise incidence is unknown. Gyure et al 6 classified GH according to location and putative pathogenic mechanism as follows: intraparenchymal GH, dural and leptomeningeal GH, IEGH, distal GH of the lung and uterus, and midline nasal glioma.…”

“…IEGH can distort the anatomy of the skull base, and if it extends inferiorly into the infratemporal fossa, it can displace the upper airway and cause orbital dysplasia. 5 In any case, surgical removal is the treatment of choice.…”