Collet-Sicard Syndrome Attributable to Extramedullary Plasmacytoma of the Jugular Foramen

Background Collet-Sicard syndrome is a rare manifestation of skull base disease involving the jugular and hypoglossal foramina. We report the first case of Collet-Sicard attributable to extramedullary plasmacytoma—multiple myeloma (EP-MM) and the second case of EP-MM precipitating a jugular foramen syndrome (JFS)-spectrum disorder. Case Description A 59-year-old woman presented with 4 months of left aural fullness and pulsatile tenderness, positional vertigo, hoarseness, and dysphagia. Examination identified left tongue weakness and nonspecific sensory abnormalities of the ear, pharynx, and throat localizing to cranial nerves IX–XII. Imaging revealed a 3.4 × 1.4 × 2.8 cm lytic lesion extending from the left jugular foramen into the posterior fossa, for which she was referred to neurosurgery and otolaryngology for consideration of resection. A second, much smaller (1.1-cm) lytic lesion in the left posterior occipital bone was incidentally discovered by the surgeon during preoperative consultation. A stereotactic biopsy of the occipital lesion was subsequently recommended, which identified plasma cell neoplasm. Serum studies and skeletal survey were consistent with MM, and a definitive pathologic diagnosis of MM with cranial EP was confirmed by bone marrow biopsy. Conclusion Tumors of the jugular foramen present with a diverse array of lower cranial nerve deficits, including Collet-Sicard syndrome, a rare subset of JFS-spectrum diseases. Paragangliomas are the most common jugular foramen neoplasms, followed by schwannomas and meningiomas; however, many other rare entities have been reported as masqueraders, and diligent work-up with consideration for preliminary biopsy is recommended, particularly in the presence of additional lesions, equivocal imaging findings, or cases arousing high suspicion.