Cutaneous Ectopic Brain Workup

Updated: Jun 16, 2022
  • Author: Camila K Janniger, MD; Chief Editor: Dirk M Elston, MD  more...
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Imaging Studies

In cutaneous ectopic brain (CEB), evaluate any bald scalp plaque or nodule with suitable noninvasive diagnostic techniques (eg, ultrasound, cranial tomograms), with input from a neurosurgeon.

Preoperative imaging may identify calvarial defects. [5] Preoperative imaging is essential to document possible intracranial involvement and to reduce the risk of penetration of the dura during resection.

Brain heterotopia may be evident on MRIs and positron-emission tomography (PET) scan images. Heterotopia may demonstrate normal or increased fluorodeoxyglucose uptake on PET scan images, sometimes confusing matters when other pathologies are being considered. [24]



Caution is obligatory because skin biopsy or needle aspiration might lead to retrograde infection should the lesion communicate with the brain. [5]

If a congenital defect overlies a large blood vessel such as the sagittal sinus, removal of what appears to be a crust of dried serum may produce a fatal hemorrhage.


Histologic Findings

The overlying epidermis in CEB is normal or somewhat atrophic because of the ectopic brain tissue impinging upon it. Brain tissue may be noted consisting of a small nodule of predominant eosinophilic fibrillary stroma, containing astrocytes, oligodendrocytes, and neurones. [25] The dermis has an island of malformed brain tissue composed of glial cells and some neurons in a pattern that may suggest abortive gyri and sulci. Vascular leptomeninges and fibrous bands, possibly representing dura, may envelop this brain tissue. Many hair follicles and sweat glands may be evident.

Histologic examination may show neural tissue staining with S-100 protein and glial fibrillary acid protein, but not with a neurofilament stain, suggesting glial cell origin.