Use of fluorescein sodium to obtain histological diagnosis of primary Central nervous system lymphoma ghost tumour despite disappearance on intraoperative magnetic resonance imaging: technical note and review of the literature.

Background and importance: Corticosteroid pre-treatment in patients with primary central nervous system lymphoma (PCNSL) can lead to the phenomenon of ghost tumours (GhT). This affects the diagnostic yield of biopsies and potentially causes misdiagnosis of the condition. The usual strategy of neuronavigation using preoperative magnetic resonance imaging (MRI) or localisation using intraoperative MRI (iMRI) can be rendered ineffective in this situation.

Clinical presentation: A middle-aged Chinese male with newly diagnosed human immunodeficiency virus infection was found to have an intracranial lesion suggestive of PCNSL. Preoperatively corticosteroid led to an attenuation of the contrast enhancing lesion on iMRI. However, intraoperative use of FS allowed the successful identification, biopsy and diagnosis of the condition.

Conclusion: FS is useful in the biopsy of PCNSL GhT even when the lesion is not seen in subsequent MRI imaging.