Management of advanced sporadic endolymphatic sac tumours: a single-centre case series

BACKGROUND: Endolymphatic sac tumours (ELSTs) are rare, locally aggressive neoplasms of the temporal bone that often present at an advanced stage due to their indolent clinical course. Complete surgical excision may be technically challenging when tumours involve the jugular foramen, cerebellopontine angle (CPA) or adjacent cranial nerves and may therefore be associated with significant neurological morbidity. OBJECTIVE: To evaluate facial nerve and radiological outcomes following planned subtotal resection with selective use of adjuvant radiotherapy in patients presenting with advanced sporadic ELST. METHODS: A retrospective review was performed of patients diagnosed with ELST and managed at the National Skull Base Centre, Beaumont Hospital. Clinical presentation, radiological findings, surgical approach, extent of resection, histopathological features, adjuvant therapy and postoperative outcomes were analysed. All patients underwent screening for von Hippel-Lindau (VHL) disease. Facial nerve function was assessed using the House-Brackmann (HB) grading system. Radiological stability was evaluated using serial postoperative magnetic resonance imaging (MRI). RESULTS: Two patients presented with locally advanced ELST involving the petrous temporal bone and skull base with cranial nerve involvement at diagnosis. Both patients underwent screening for von Hippel-Lindau disease. Both underwent transmastoid subtotal resection to preserve neurological function. One patient subsequently received adjuvant radiotherapy, while the second was managed with radiological surveillance alone. Patient 2 improved from House-Brackmann grade V to grade II, while Patient 1 maintained grade II function. Serial postoperative MRI demonstrated stable residual disease. CONCLUSION: In selected cases of advanced sporadic ELST, planned subtotal resection with selective adjuvant radiotherapy may preserve cranial nerve function while maintaining short-term radiological stability.