Metastatic choroid plexus papilloma: a case report.

Choroid plexus papillomas (CPPs) are generally regarded as benign tumours, with a favourable long-term prognosis. Complete resection should result in cure. We present a case of diffuse craniospinal seeding from an apparently completely resected fourth ventricular primary tumour. A 51-year-old male is discussed, who presented 5 years following complete resection of a CPP from the fourth ventricle, with a progressive history of left sided tinnitus, hearing loss, impotence and recent low back pain. Imaging demonstrated multiple craniospinal lesions explaining his symptomatology. Differential diagnosis lay between long standing CSF seeding, malignant transformation in the primary tumour, or metastatic spread from an undefined source. He underwent whole body FDG-PET scan which demonstrated a single metabolically active lesion in the sacral canal. A subtotal excision biopsy of this sacral lesion was performed which was indistinguishable histologically from the primary tumour resected from the fourth ventricle. Histological and functional imaging characteristics of the primary tumour have been unhelpful in predicting its subsequent behaviour. The present case illustrates the extremely rare consequences of metastases from this histologically benign tumour and adds to the literature on metastatic craniospinal disease.