Radiology Teaching Files > Case 3607626

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Contributed by: alvin yamamoto.
Patient: 1 year 7 month old male

19-month-old with acute onset altered mental status


Fig. 1
Findings: Parasagittal midline T1 shows mixed signal intensity mass centered within the posterior third ventricle/pineal region.  There is obstructive hydrocephalus and a fat-fluid level within the lateral ventricle.  Scattered fat droplets are seen within the subarachnoid spaces.

Ruptured 3rd ventricle dermoid cyst.  DDx: Ruptured pineal teratoma.


Intracranial dermoids are congenital inclusion cysts, containing various dermal elements.  They are rare and comprise < 1% of primary intracranial tumors.  Age of presentation 30-50y.  HA and CN mass effect usual presentation.  Rupture with chemical meningitis occurs in only 7%.  This patient demonstrates typical appearance of rupture with intraventricular and subarachnoid extension. 

Occipital/nasofrontal dermal sinus
Goldenhar syndrome (oculoauriculovertebral dysplasia)

Usually near midline, in contrast to epidermoid cyst
Fat, calcification, soft tissue use fat suppression
Enhancement with chemical meningitis
DDx midline masses:
Epidermoid cyst

Rupture 7%, meningitis, vasospasm
Recurrence following excision
Malignant degeneration reported

Osborn AG, et al. Diagnostic imaging: brain.  Amirsys, 2005.

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Additional Details:

Case Number: 3607626Last Updated: 01-09-2006
Anatomy: Cranium and Contents   Pathology: Benign Mass, Cyst
Modality: MRExam Date: Access Level: Readable by all users
Keywords: dermoid, teratoma, germ cell, rupture

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