84 year old woman with spells of right upper limb weakness and numbness

Teaching NeuroImagesNeurology

Resident and Fellow Section

© 2014 American Academy of Neurology

Vignette

• History of: – Prior strokes to left parietal and right occipital

lobes.– Metastatic breast cancer with skull involvement.

O’Gorman et al© 2014 American Academy of Neurology

Imaging

O’Gorman et al© 2014 American Academy of Neurology

Imaging

O’Gorman et al© 2014 American Academy of Neurology

EEG pattern associated with a skull osteolytic lesion in breast cancer

• Breach effect or breach rhythm – a focal increase in amplitude of alpha, beta and mu

rhythms detected at or near the site of a bony skull defect.[1]

– Usually associated with surgical skull defects.– Also seen in osteolytic lesions of the skull.[2]– No association with epilepsy.– EEG alteration may be confused with focal

epileptiform discharges.• Final diagnosis: focal seizure

O’Gorman et al© 2014 American Academy of Neurology