1100 Ten years later he developed slowly progressive headache, and a few weeks later he woke up with an expressive dys- phasia. During hospitalization he developed a right sided hemiparesis with right hemianopia and he suffered from frequent focal epileptic seizures of the right arm and leg, for which he received valproate and levetiracetam. MRI showed focal gyral thickening and enhancement of the left parieto- occipital lobe where metastases had not been observed previously (Fig. 2a–d). Apart from diffuse leukoencepha- lopathy, presumably due to the earlier brain radiotherapy, Fig. 2 60-year-old man who was treated 10 years previously for brain metastases of bronchial carcinoma with chemo- and radiation therapy, now presenting with gradually progressive headache and acute dysphasis. a T2 weighted MR image showing diffuse gyral swelling and signal increase in the left parietal lobe. b T1 weighted MR image after gadolinium administration showing abnormal regional leptomeningeal enhancement. c T2 weighted FLAIR MR image showing diffuse gyral swelling and signal increase in the left occipital lobe. d T1 weighted MR image after gadolinium adminis- tration showing abnormal leptomeningeal enhancement. MR images after 4 months. e T2 weighted MR image no residual signal abnormalities. f T1 weighted MR image after gadolinium adminis- tration showing no abnormal leptomeningeal enhancement 123 J Neurol (2011) 258:1098–1104 there were no signs of recurrent brain metastases. Repeated CSF analysis showed a slightly elevated protein level, but no leptomeningeal metastases (Table 1). There were no clues for extracranial tumour recurrence. During the hospital stay he had a gradual clinical improvement and was discharged fully recovered. A follow-up MRI 3 months after discharge also showed complete resolution of the abnormalities in the left parieto-occipital cortex (Fig. 2e, f). Patient 3 In 1997 at the age of 42 years, this man suffered from an epileptic seizure caused by an anaplastic oligodendrogli- oma in the left hemisphere. The tumour was resected and he subsequently received focal brain radiation (60 Gy in 30 fractions). He was discharged from hospital on valproate. Two years later he was admitted to the hospital twice within a short time period with reversible neurological deﬁcits: dysphasia, right hemianopia, headache and neglect of his right arm. Imaging showed no signs of recurrent tumour, but possibly a small infarction in the left occipital region and some diffuse white matter disease, possibly due to radiation. An EEG showed no epileptic activity. Diag- nosis of reversible ischemic neurological deﬁcit was hypothesized, possibly due to former radiotherapy. Three years thereafter he was again taken into hospital with focal epileptic seizures of the right side of his face. He suffered from headache, progressive aphasia, right hemia- nopia and mild paresis of his right arm and leg. An MRI scan now showed diffuse cortical enhancement of the left occipital and temporal cortex (Fig. 3a, b). This enhance- ment disappeared on a subsequent MRI performed 8 days later (Fig. 3c, d). An EEG showed no epileptic activity. Clinically, he recovered substantially. Three years later he was again admitted to hospital because of a new episode of worsening aphasia and paresis of his right arm and leg. MR imaging, similar to 3 years earlier, demonstrated diffuse cortical enhancement of the left occipital and temporal cortex (Fig. 3e, f). Although CSF examination showed some atypical cells, he again partially recovered spontaneously and almost completely, making leptome- ningeal seeding unlikely (Table 1). A follow-up MRI scan performed 1 month later again showed complete disap- pearance of the contrast enhancement (Fig. 3g, h), and he recovered afterwards in a rehabilitation centre. On longer follow-up, he was treated successfully with temozolomide chemotherapy for local tumour recurrence. Patient 4 In 1999 at the age of 34 years, this man suffered from an epileptic seizure caused by a right temporal anaplastic