Plasmacytoma of the petrous temporal bone.

Extramedullary plasmacytoma is a rare soft-tissue malignancy of plasma cells. Some 80% of these tumors occur in the head and neck, 28% in the nasal cavity, and 22% in the paranasal sinuses. (1,2) Approximately 20% of the head and neck tumors are initially associated with multiple myeloma. (1)

We evaluated a 41-year-old woman who had a history of multiple cranial neuropathies on the right, particularly in the trigeminal nerve. Computed tomography (CT) detected a soft-tissue mass that involved the petrous portion of the right temporal bone and extended into the posterior right parasellar area (figure). Biopsy identified the lesion as a plasmacytoma, and the patient underwent local radiation therapy.

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Plasmacytoma has been reported to involve the temporal bone and produce a lytic lesion of fairly homogeneous soft-tissue density (because of its cellularity), and it can be seen on both CT and magnetic resonance imaging. (2,3) Although plasmacytoma can occur as an isolated lesion, many patients eventually develop multiple myeloma. (1)

References

(1.) Som PM, Brandwein MS. Tumors and tumor-like conditions. In: Som PM, Curtin HD, eds. Head and Neck Imaging. Vol. 1, 4th ed. St. Louis: Mosby. 2003:261 373.

(2.) Chiang SK, Canalis RF, Ishiyama A, et al. Plasmacytoma of the temporal bone. Am J Otolaryngol 1998;19:267-73.

(3.) Dazert S, Baier G, Aletsee C, Hagen R. [Extramedullary plasmacytoma--manifestation in petrous bone]. Laryngorhinootologie 1997;76:559-61.

From the Department of Radiology, Hospital Angeles, Mexico City (Dr. Ruenes), and the Department of Radiology, Louisiana State University Health Sciences Center, New Orleans (Dr. Palacios).