35 y/o woman with soft tissue swelling on the back of her head
MRI CT head neuro
Publication Date: 30 October 2003
A lenticular-shape fluid collection is seen in the right occipital region that shows an enhancing rim with IV contrast. A defect is seen in the calvarium with an extracranial, rim-enhancing collection. The MRI was actually performed 2 weeks earlier for headache however the findings were missed until the patient returned for the CT scan.
Epidural abscess with extension through calvarium resulting in a subperiosteal abscess
This is an unusual case. Intracranial epidural abscesses occur only about 20% as frequent as subdural abscesses and are frequently associated with a recent surgical procedure or trauma. Epidural abscesses are associated with paranasal sinus infections, mastoiditis and otitis. This patient has a history of otitis a month or two before the initial MR scan but did not have any trauma or surgical procedure.
This case is also somewhat similar to the Pott's Puffy Tumor which is a case of frontal sinusitis with associated osteomyelitis and subperiosteal abscess. Epidural abscess can be a complication of Pott's Puffy Tumor. In this case, it appears that the epidural abscess occured first, probably as a complication of otitis media with secondary osteomyelitis and development of a subperiosteal abscess.