JUGULAR FORAMEN EXTRAMEDULLARY PLASMACYTOMA PRESENTING AS AN EXTERNAL AUDITORY CANAL MASS WITH LOWER CRANIAL NERVE PALSIES: A CASE REPORT

Abstract

Background: Solitary extramedullary plasmacytoma is a rare plasma cell neoplasm characterized by localized proliferation of monoclonal plasma cells outside the bone marrow. Jugular foramen involvement is particularly uncommon and often presents with multiple cranial neuropathies.

Case Presentation: We report a woman who presented with 3 months of progressive left occipital stabbing headache and 1 week of left otalgia, tinnitus, and hearing loss, followed by deviation of angle of mouth to the right, dysphonia, and dysphagia. Otoscopy showed a fleshy mass arising from the posterior wall of the left external auditory canal. Neurological examination revealed left sided LMN type of facial nerve palsy, reduced palatal movement with left vocal cord palsy, and left hypoglossal nerve palsy. MRI demonstrated a large avidly enhancing extra-axial lobulated lesion centered at the left jugular bulb/foramen, extending into the middle ear cavity with surrounding osseous erosion. PET-CT showed no other lesions. Serum protein electrophoresis with immunofixation and urine Bence–Jones proteins were negative. A subtotal excision was performed, achieving decompression of the lower cranial nerves. Histopathology was suggestive of an extra medullary plasmacytoma. Postoperative MRI confirmed residual disease around the jugular foramen. Adjuvant radiotherapy was initiated.

Conclusion: Skull base EMP should be considered in the differential diagnosis of jugular foramen masses with EAC involvement and lower cranial neuropathies. Tissue diagnosis is essential, and combined surgical decompression with adjuvant radiotherapy can provide durable local control in unresectable or residual disease.