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Skull vault epidermoid

Case contributed by Dr Chris O'Donnell


Recent blow to left parietal region. CT scan to assess for intracranial injury. No previous history of malignancy.

Patient Data

Age: 80 years
Gender: Female

Small left parietal scalp hematoma (arrow) with adjacent expansile soft tissue mass in the skull vault.  Soft tissue density not fat so not a dermoid. Bone margins are regular or scalloped.  Incidental right skull vault osteoma.


MRI for further clarification of CT findings

Mass shows restricted diffusion (confirmed on the ADC map indicative of epidermoid).

Case Discussion

A benign, slow-growing lesion of the skull due to aberrant epidermal inclusion in the calvaria. Differential diagnosis is Langerhans cell histiocytosis in a child/young adult, metastasis and plasmacytoma. Key to diagnosis is the intradiploic location with well-demarcated lysis expanding both the inner and outer tables of the skull and well defined borders. The MRI findings of marked restricted diffusion are typical of epidermoid.

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Case information

rID: 30621
Published: 22nd Aug 2014
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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