ABSTRACT

A 68-year-old woman with a history of multiple myeloma presented to the clinic with pain and vision loss in her right eye. Proptosis was observed in her right eye and eye movements were restricted in all directions. Best corrected visual acuity was 3/10 in her right eye. On biomicroscopic examination, hyperemia and subconjunctival hemorrhage were present. Fundus examination of the right eye revealed optic disc edema and choroidal folds. In magnetic resonance imaging two orbital masses were detected. Based on the patient’s history and ocular examination, we evaluated the masses as orbital metastasis of multiple myeloma. Palliative radiotherapy was recommended.

Introduction

Multiple myeloma (MM) is a malignancy characterized by abnormal plasma cell proliferation and is generally confined to the bone marrow. However, 3% of cases may develop extramedullary involvement, defined as the formation of solid plasmacytomas outside the bone marrow.¹Extramedullary involvement usually occurs in the upper skeletal system, but rarely orbital manifestations are observed.^2,3,4The most common ocular signs and symptoms in orbital involvement are proptosis, redness, pain, diplopia, and impaired vision; proptosis is an indicator of metastasis and recurrence. This report presents a case of orbital involvement observed during follow-up of an MM patient in remission.

Discussion

Ocular findings in MM may arise from systemic effects of the disease (increased blood viscosity) or infiltration of plasma cells into ocular tissues.⁴These ocular findings may include crystalline corneal deposits, exudative macular detachment, ciliary body cysts and retinal hemorrhage. Though rare, orbital involvement may be an extramedullary manifestation. The most common clinical sign of orbital involvement in MM is unilateral proptosis, while hyperemia, pain, diplopia and low vision occur less often.⁵There are also reports of bilateral proptosis in some cases.⁵Similarly, our case presented with proptosis, subconjunctival hemorrhage, pain and vision loss. Her ocular motility limitation, optic disc edema and choroidal folds resulted from a metastatic mass located posterior to the globe which was invading the extraocular muscles and applying pressure to both the globe and the optic nerve. All of these findings have been observed in similar cases of orbital involvement.^1,2,6,7,8

Approximately 9% of orbital tumors in adults are metastases, and orbital metastases usually originate from lung and breast cancers.⁹There have also been reports of kidney, pancreas, prostate and gastric cancers forming orbital metastases.^10,11The presence of metastasis in MM indicates a poor prognosis. Orbital metastases in particular have worse survival rates compared to other extramedullary plasmacytomas.⁶Mean expected survival for patients with recurrence is 12 months in the absence of systemic involvement, less in cases with systemic involvement. Of all malignancies occurring during remission, approximately one in three is orbital.

RT is an effective palliative therapy for MM patients, especially those with symptomatic local manifestations.^12,13Palliative RT is indicated for deficits related to pain, bone involvement, spinal cord compression, root compression and cranial nerve involvement. We recommended RT in this case due to the pain that accompanied the orbital involvement.

Conclusion

Proptosis has an important role in the differential diagnosis of malignancies. In cases like this, imaging should be done immediately and the differential diagnosis should be considered. It should be kept in mind that proptosis can be the first sign of relapse in a patient previously diagnosed with MM.