MR CHARACTERISTICS OF PRIMARY EXTRAMEDULLARY PLASMACYTOMA IN THE HEADAND NECK

PURPOSE: To define MR characteristics of primary extramedullary plasma cytoma in the head and neck using a variety of plain and contrast-enha nced MR protocols. METHODS: Six patients with primary extramedullary p lasmacytoma in the head and neck were examined clinically and with MR imaging at 1.5 T. The morphologic appearance and signal intensities of the lesions were analyzed and the results of the imaging findings wer e compared with histopathologic findings. RESULTS: Qualitative analysi s showed that five lesions were oval and sharply demarcated without si gns of infiltration; the other lesion filled the parapharyngeal space bilaterally. On T2-weighted sequences, the lesions had moderate signal intensity. On plain T1-weighted sequences, the tumors were isointense or slightly hyperintense with respect to surrounding muscles; after a dministration of contrast medium, four lesions showed notable enhancem ent, with distinct central inhomogeneity. CONCLUSION: Although morphol ogic features or evidence of contrast enhancement do not assure certai n diagnosis of extramedullary plasmacytoma, these MR imaging character istics should prompt the radiologist to include this rare lesion in th e differential diagnosis.