Objective: Primary solitary extramedullary and multiple solitary plasmacytomas are rare manifestations of plasma cell tumors. This study reviews their imaging spectrum in 12 patients.

Conclusions: Imaging features of primary solitary extramedullary and multiple solitary plasmacytomas are nonspecific but are compatible with solid tumors that are isointense on T1-weighted images and iso- to hyperintense on T2-weighted images relative to muscle and white matter with variable enhancement. Large tumors may show necrosis and destruction, infiltration, or encasement of adjacent structures. Multiplicity of lesions and regional lymphadenopathy were evident on imaging in only five cases each. Imaging alone cannot differentiate these tumors from more common malignant entities such as carcinoma, meningioma in cases of intracranial extramedullary plasmacytomas, or metastasis from other primaries. The role of imaging should be focused on early detection of additional or recurrent lesions and the presence of regional lymphadenopathy, which will influence clinical management.