RESUMO
BACKGROUND: The distinction between central and peripheral facial nerve palsy can be difficult but is very important for the workup and treatment. A tumefactive demyelinating lesion (TDL) is a rare condition that can sometimes cause diagnostic difficulties due to its similarity to a brain tumour. CASE DESCRIPTION: We present a 20-year-old female patient who visited her GP with a discrete right-sided drooping corner of her mouth. The GP started treatment with oral glucorticoids because of presumed Bell's palsy and referred her to the neurology outpatient clinic. Repeated neurological examination showed central facial palsy on the right side of the face. An MRI study of the brain revealed a single large contrast-enhanced abnormality in the left hemisphere that was diagnosed as TDL after exclusion of other causes. In view of the limited number of clinical symptoms, an expectative policy was conducted. The patient recovered spontaneously and repeated MRI studies showed partial regression of TDL. CONCLUSION: TDL is often considered to be a first presentation of multiple sclerosis. Accurate analysis with MRI can help in making a diagnosis without the need for a biopsy.
