Fig. 1T2-weighted fluid-attenuated inversion recovery (A) and T2-weighted turbo-spin echo (B) brain magnetic resonance imaging showing a 5-cm mass with a cystic portion and a fatty component in the left frontotemporal and suprasellar areas. (C) Computed tomography of the ostiomeatal unit (non-contrast). A large cyst is present in the left middle cranial fossa. Left paramedian herniation of a solid cystic mass with a focal fat component into the left nasal cavity, ethmoid sinus, and left medial extraconal orbital space through the anterior skull base defect.
Fig. 2Sections of the frontotemporal mass (A-D) and the cysts (E-H). (A) The mass is composed of well-formed and disorganized cerebellar tissue. (B) Cerebellar tissue shows a Purkinje cell layer, a molecular layer, and external and inner granule cell layers. (C) Neocortical tissue has a focal cortical dysplasia-like appearance, with regard to subpial gliosis, a persistent granule cell layer, and dyslamination. (D) Adipose tissue is mixed with heterotopic brain tissue. (E) The glioependymal cyst is composed of ependymal cells lining variably thickened glial and fibrovascular tissues. (F) Glial tissue is positive for glial fibrillary acidic protein. (G) The arachnoid cyst, present alongside the glioependymal cyst, is lined with a cuboidal layer of meningothelial cells and fibrous tissue. (H) The meningothelial cells are positive for epithelial membrane antigen.
Table 1.Summary of reported cases of intracranial extracerebral glioneuronal heterotopia
|
Previously reported cases (19 cases in 18 journals) |
Present case |
Age |
25 wk (embryo)-56 yr |
4 mo |
Sex |
14:3 (female:male) |
Female |
Location |
MCF, Lt. (n = 5), Rt. (n = 2), ACF, Lt. (n = 3), sphenoid wing, Lt. (n = 2), suprasellar region (n = 2), retrosellarl region (n = 1), subfrontal region (n = 1), occipital region (n = 1), frontotemporal region, Rt. (n = 1), cerebellomedullary cistern (n = 1) |
Frontotemporal and suprasellar region, Lt. |
Histologic composition (other than glioneuronal tissue) |
Ependymal cell (n = 7), choroid plexus (n = 7), cyst(s) (n = 6), adipose tissue (n=5), microcalcification (n=4), cerebellar tissue (n = 2), dilated vessels (n = 2), other components: fibrous tissue, muscle fascicle, peripheral nerve, ocular pigmented epithelium, dyslaminated gray matter, etc. |
Cerebellar tissue, disorganized, large cyst, adipose tissue, Dilated vessels |
Accompanying congenital anomalies |
Cleft palate (n = 2), cleft lip (n = 1), hemifacial hypoplasia with anophthalmia of orbit, Rt. (n = 1), other: low-set ear and microgenia (n = 1) |
Atrial septal defect |