Parietal intradiploic encephalocele: Report of a case and review of the literature

Abstract

Encephaloceles consist of brain tissue and meninges that has herniated through a skull defect, usually located in the midline. They are seen more commonly in children and very rarely in adults. We present a case of an 84-year-old patient who was incidentally diagnosed with a lytic bone lesion in the right parietal intradiploic space, after computed tomography of the head was performed. A magnetic resonance imaging scan of the brain showed herniation of brain tissue through the defect. Magnetic resonance imaging was crucial in demonstrating the presence of parenchyma and its continuity with the rest of the brain, consequently distinguishing it from other entities. We report the imaging findings of a parietal indradiploic encephalocele with its differential diagnosis and a review of the relevant literature.

Symptomatic Parietal Intradiploic Encephalocele—A Case Report and Literature Review

“…Of the case reports, the most common symptoms are hemiparesis/weakness 11,12,17 (four patients including the present study), seizures 5,17 (two patients), palpable mass 9,10 (two patients); one was incidentally found. 18 Surgical repair with or without excision of the herniated brain parenchyma is generally performed in symptomatic patients. Clinical response is generally favorable with minor improvement in symptoms to completely asymptomatic on follow-up.…”

“…Of the case reports, the most common symptoms are hemiparesis/weakness 11 12 17 (four patients including the present study), seizures 5 17 (two patients), palpable mass 9 10 (two patients); one was incidentally found. 18 …”

“…Differential diagnosis includes epidermoid or dermoid cyst, cavernous hemangioma, eosinophilic granuloma, plasmacytoma, metastasis, and osteosarcoma. 18 MRI is necessary to establish a diagnosis. Herniation of brain parenchyma through a dural defect into intradiploic space is what separates this lesion from the rest on the differential, as is seen in our case.…”

Intradiploic Encephalocele at the Parietal Bone: A Case Report and Literature Review

“…Encephaloceles are protrusions of the brain parenchyma through osseous defects of the skull base or cranial vault [ 1 ]. It may develop congenitally (similar to the neural tube defect) or may occur after acquired events, such as infection, trauma, neoplasms, and iatrogenic causes [ 2 3 ]. The incidence of the congenital form has been estimated at 1 in every 3,000–10,000 live births [ 4 ].…”

“…In cases where the defect occupies only the dura and inner table with an intact outer table of the skull, parenchymal herniation occurs in the intradiploic space and are called intradiploic encephaloceles [ 7 ]. Especially, off the midline parietal encephaloceles are rare, comprising only 1% of all cerebrospinal malformations and 10% of encephaloceles [ 2 8 ]. Here, we report a case of parietal intradiploic encephalocele during a 2-year follow-up with CT and MR images.…”