Orbital manifestations of plasmacytic lymphoproliferations.

Orbital involvement by plasmacytic lymphoproliferative disorders is rare. Presented are four cases, with different clinical onsets and courses, demonstrating the diversity of expression of lymphoproliferative plasma cell lesions of the orbit. The first patient presented with a slowly developing palpable mass in the upper and anterior orbit. This localized lesion proved to be a reactive plasma cell proliferation. The second case had a 3-month history of proptosis, diplopia, and droopy eyelid and a pulsatile temporal mass with bone destruction. Results of biopsy and systemic investigations showed a solitary plasmacytoma of bone. In the third case, a patient with a known multiple myeloma for 2 years presented with a progressive osteolytic mass which proved on biopsy to be a plasmacytoma. At the time, she also had other active bone lesions. The fourth case presented as a possible orbital cellulitis in a man with known multiple myeloma for 2 years. He proved to have disseminated myeloma, the orbital infiltrate being secondary to sinus involvement. The differential diagnosis for each case can be quite involved. Each case required a biopsy for an accurate diagnosis in addition to a complete clinical, radiographic, and laboratory workup. The pathologic features of each tumor can be misleading. These will be discussed as well as the use of ancillary diagnostic methods such as electron microscopy and immunohistochemistry to further characterize each lesion. The clinical course and treatment modalities will be discussed.