Jugular Foramen Plasmacytoma Mimicking Paraganglioma

Introduction: Jugular foramen lesions are rare and pose significant diagnostic and surgical challenges. Paragangliomas are the most common lesions arising from this location, accounting for 60 to 80% of cases, followed by schwannomas, and meningiomas. In this case report, we present an unusual case of a plasmacytoma mimicking the clinical and radiographic features of a paraganglioma.

Case Presentation: A 63-year-old female presented with a 6-month history of left sided pulsatile tinnitus and aural fullness, which gradually progressed to vocal hoarseness and difficulty swallowing. The neurologic examination revealed only decreased hearing on the left side. Magnetic resonance imaging demonstrated a large solid mass with contrast enhancement eccentric to the left of the jugular fossa, involving the petrous apex, portions of the left clivus, left Meckel’s cave, left carotid canal, left porus acoustics, and portions of the left posterior cavernous sinus. Octreotide scan showed intense abnormal uptake of the left jugular foramen mass consistent with paraganglioma. Preoperative angiography showed a hypervascular mass with large external carotid feeders, resembling a paraganglioma. A preauricular translabyrinthine approach to the infratemporal fossa was used to achieve a subtotal resection of the tumor. The cranial base was reconstructed with a vascularized temporoparietal flap and fat graft. Pathology demonstrated well-differentiated plasma cells consistent with plasmacytoma. Postoperative PET scan demonstrates diffuse skeletal activity suggestive of multiple myeloma and patient now undergoing chemotherapy treatment.

Discussion: Lesions involving the jugular foramen present as various diagnoses. While skull lesions are common in multiple myeloma, plasmacytomas of the jugular foramen are rare. There are only three cases in the literature of jugular foramen plasmacytomas. In all cases, the lesion was mistaken for a paraganglioma, until pathology from biopsy or surgical resection demonstrated plasmacytoma. Jugular foramen plasmacytomas may be difficult to distinguish from paragangliomas preoperatively in that both have intense octreotide uptake as well as hypervascularity. Biopsy of the suspected lesion, laboratory studies including serum protein electrophoresis and urinary Bence Jones protein, as well as FDG-PET/CT scanning may help to differentiate paragangliomas from plasmacytomas. Plasmacytomas may exist as a solitary lesion or a symptom of multiple myeloma. It is important to distinguish as primary treatment for solitary extramedullary plasmacytomas consists of surgery and/or radiation therapy, whereas mainstay multiple myeloma treatment is with chemotherapy and possible autologous hematopoietic cell transplantation.

Conclusion: Plasmacytomas while rare, may mimic paragangliomas in clinical as well as radiographic findings and should be included in the differential diagnosis for jugular foramen tumors. Early identification of multiple myeloma may alter treatment and prognosis.