A Case of Pituitary Germinoma With Complete Recovery of Visual Field

Abstract

Abstract Central nervous system germ cell tumours (GCTs) are rare, accounting for 0.1-3.4% of all primary brain malignancies. Intracranial GCTs (ICGCTs) usually arise within the pineal recess (50-65%), sellar-suprasellar region (25-35%) and rarely in the basal ganglia-thalamus (5-10%). A peakonset occurs during the second decade of life with a median age at diagnosis between10-12 years and a male predominance. Histologically, ICGCTs are classified into germinomas accounting for two thirds of cases and non-germinomatous GCTs. ICGCTs present with clinical features dependent on their location and tumour size. Symptoms most often arise from compressed optic structures, increased intracranial pressure and central endocrine abnormalities, particularly diabetes insipidus (DI). Clinical findings combined with elevated tumour marker levels within the serum and/or cerebrospinal fluid (CSF) can be diagnostic. Case: A 30-year-old lady who survived a childhood leukaemia presented as an emergency with a two-month history of headaches, dizziness and near-complete visual loss. Cranial MRI identified a large sellar mass with suprasellar extension compressing the optic chiasma and hypothalamus. Biochemical and endocrine profiles confirmed diabetes insipidus, hypocortisolaemia and hypothyroidism all requiring hormone replacement. Visual field examination revealed total left visual loss and a right temporal hemianopia. Cerebrospinal fluid analysis identified an elevated human chorionic gonadotropin (HCG) level at 16 IU/L (normal <2), with a normal alpha-fetoprotein (AFP) level. Both tumour markers were normal in the serum. Emergency Etoposide-Cisplatin (Em-EP) chemotherapy was initiated for a suprasellar GCT followed by the EPOMB-ITMTX regimen [Etoposide-Cisplatinwith intrathecal Methotrexate (ITMTX) alternating with Vincristine-Methotrexate-Bleomycin]. After four cycles EPOMB-ITMTX, the vision was fully restored, brain MRI demonstrated an excellent radiological response and the CSF HCG normalised. Our patient received volumetric-modulated arc cranial radiotherapy (VMAT) with a total 54 Gy in 16 fractions. She remains well without disease recurrence for 14 months. Tumour markers are normal with stable MRI brain and whole-spine. Endocrine follow-up confirms recovery in all pituitary axes except the gonadotrophins for which she remains on hormone replacement therapy. Conclusion: This case demonstrates an excellent outcome for a young adult diagnosed with a suprasellar GCT treated with chemotherapy followed by stereotactic radiotherapy. It highlights the importance in keeping a high clinical index of suspicion in young adults presenting with a midline intracranial tumour, visual dysfunction and an endocrinopathy. CSF analysis identified an elevated tumour marker level, which bypasses the need for a histological diagnosis.