Cutaneous Ectopic Brain Differential Diagnoses

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

See the list below:

  • Encephalocele [14]

  • Meningocele

  • Cutaneous ectopic meningioma (psammoma) [15, 16, 17]

  • Neurofibroma

  • Porokeratosis of Mibelli

  • Triangular alopecia

  • Nevus sebaceus of Jadassohn

  • Aplasia cutis congenita: Alopecia overlying cutaneous ectopic brain may suggest this diagnosis.

  • Hemangioma

  • Lymphangioma

  • Cephalohematoma

  • Melanotic progonoma

  • Myxopapillary ependymoma (possibly)

  • Ectopic orbital meningoma, which may be evident as a medial canthal mass [18]

The prominent collarette of hair that may be seen in persons with cutaneous ectopic brain (CEB) may also be seen in other neurocutaneous disorders (eg, encephalocele, cutaneous meningioma). [4, 19] Consider the possibility of a dermal sinus or a direct connection to the meninges or central nervous system when assessing congenital defects.

Encephaloceles are usually in the midline scalp, either hairless or with a collarette of hair. The nasal glioma, similar to CEB, may have no connection to underlying central nervous system structures. It appears on the nose as a smooth, often polypoid tumor. Cutaneous heterotopic meningeal nodules (cutaneous meningiomas) are seen most often at birth or in childhood as small subcutaneous fibrous nodules. [20] Primary ectopic meningioma may also occur on the tongue. [21]  

Cutaneous meningiomas may also require distinction. [20]

Heterotopic CNS tissue may also occur in the form of an ethmoidal polyp. One should distinguish these from meningoencephalocele, as the latter have an anatomical connection with central nervous system tissue. Contrast-enhanced imaging is essential to show no connections with intracranial tissue. [22]

Glial heterotopia or ectopic brain may appear as a dacryocystocele. [23]

Differential Diagnoses