A neonate born at 38 weeks’ gestation by caesarean section for failure to progress was noted to have increased head circumference at birth and cranial US showed significant hydrocephalus. Contrast-enhanced MRI at 4 days of age revealed an avidly enhancing mass in the right cerebellopontine angle (Fig. 1). MR spectroscopy centred on the mass demonstrated a single choline peak at 3.2 ppm (Fig. 2). Histology of the resected mass after embolization showed it to be a choroid plexus papilloma.

Fig. 1
figure 1

Coronal T1-weighted MR image after gadolinium administration

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Fig. 2
figure 2

MR spectrum (TE 144 ms)

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Choroid plexus papillomas represent about 10% of brain tumours identified in infants [1]. These are most commonly seen in the lateral ventricles [1], although an extraventricular posterior fossa origin has been reported. Tumours in such a location can result from herniation of the tumour through the foramen of Luschka or from de novo development in the choroid plexus lying outwith the fourth ventricle at the cerebellopontine angle, referred to as Bochdalek’s flower basket [2]. The location, enhancing characteristics and MR spectroscopic appearance are characteristic of a choroid plexus tumour in this uncommon location.