CASE 15672 Published on 15.04.2018

Atretic parietal cephalocele



Case Type

Clinical Cases


Klemen Mihelcic, Alja Longo

University Medical Centre Ljubljana
Zaloska cesta 2
1000 Ljubljana, Slovenia

1 years, male

Area of Interest Neuroradiology brain ; Imaging Technique MR, Ultrasound
Clinical History
1-year-old boy presented with a soft, non-painful midline parietal lump of the scalp, which was present since birth.
Imaging Findings
Head US revealed a sharply demarcated hypoechoic lesion in the subcutaneous tissue of the parietal region with a thin tubular connecting structure towards the sagittal suture. Doppler study showed no flow within the lesion. (Fig.1)
Head MRI showed a T1 hypointense, T2 hyperintense triangular lesion in the soft tissue of the central parietal scalp, which showed thin peripheral enhancement after gadolinium contrast agent administration. (Fig. 2, 3) A connecting narrow fibrous strip passed through a small osseous defect in the sagittal suture beneath the lesion. (Fig. 4) Intracranially a vertical falcine vein with a cerebrospinal fluid tractus were seen leading towards the defect in the calvaria. The findings were consistent with atretic parietal cephalocele.
Additionally, multiple confluent nodular lesions of grey matter intensity were seen bilaterally in periventricular regions of the lateral ventricles, distorting the outlines of the ventricles. The findings were consistent with subependymal grey matter heterotopia. (Fig. 5)
Cephaloceles are congenital herniations of intracranial structures (dura, fibrous tissue and dysplastic brain tissue) through a skull defect. They have an incidence of 1 in 3500 - 5000 live births. Atretic cephaloceles (AC) represent 37.5 - 50% of all types of cephaloceles. [1, 2]
Approximately half of the reported cases are located parietally. [3]
Prevalence of associated intracranial anomalies is higher when AC is located in the parietal region. These include grey matter heterotopia, Walker–Warburg syndrome (lissencephaly, hypoplasia of the metencephalon and moderate to marked ventricular enlargement), lobar holoprosencephaly, Dandy–Walker syndrome, hypogenesis of the corpus callosum, extra-axial cysts, microphthalmia, and retro-ocular cysts. [3, 4]
Diagnosis is generally established by characteristic imaging findings. Although cephaloceles can be detected by prenatal ultrasound, due to low incidence and small size the prenatal diagnosis is uncommon. US and MRI are the imaging modalities of choice especially in children. [1, 2] Other imaging techniques that can be used to visualise the defect include skull radiograph and head CT. [2]
Common findings include subgaleal soft tissue mass with an intracranial extension via a sharply demarcated calvarial defect (cranium bifidum), CSF tract and vertical falcine vein point to the subcutaneous scalp mass, vertically oriented primitive falcine vein, fibrous stalk connecting the cephalocele, focal fenestration of superior sagittal sinus at the atretic parietal cephalocele, prominence of the superior cerebellar cistern and suprapineal recess, superior peaking of the posterior tentorium, and spinning top configuration of the tentorial incisura. [5]
Major differential diagnosis include encephalocele, sinus pericranii and dermoid cyst. Encephaloceles differ from AC in that they contain CNS tissue. Sinus pericranii presents as a subscalp soft tumour filled with venous blood that empties when the patient is standing and refills when the patient is lying. Dermoid cysts tend to present at the occipital midline. Calvarial defects seen with dermoid cysts are rounded and narrow from the outside inward, the opposite of that seen with AC. [1, 2]
With no other CNS abnormalities, the majority of patients with parietal AC have a good prognosis. [4]
Most cases of AC are treated surgically with excision of the cystic lesion and oversewing of the tract formed by the dura. [2, 4]
Differential Diagnosis List
Atretic parietal cephalocele with concomitant subependymal grey matter heterotopia
Sinus pericranii
Dermoid or epidermoid cyst
Sebaceous cyst
Vascular lesions (haemangioma)
Final Diagnosis
Atretic parietal cephalocele with concomitant subependymal grey matter heterotopia
Case information
DOI: 10.1594/EURORAD/CASE.15672
ISSN: 1563-4086