The patient had right orbital superolateral marrow infiltrative lesion. Differential possibilities include metastasis, plasmacytoma, or lymphoma. Excision and pathology revealed plasmacytoma. Subsequent bone marrow aspirate was normal. with low count plasma cells. No other lytic lesions on PET CT. This means this is a solitary bone plasmacytoma which represents an isolated form of multiple myeloma involving a solitary bone.

Solitary bone plasmacytoma differs from multiple myeloma by the presence of only one lesion (bone or soft tissue), normal bone marrow (<5% plasma cells), normal skeletal surveys, absent or low paraprotein, and absence of end-organ damage.

Solitary bone plasmacytomas usually progress to multiple myeloma in 3 to 5 years.