Some Orbital Confusion

In spite of 2 years without treatment his clinical examination had not changed. One month later acuity remained 20/25 bilaterally, with no APD, no change in VF, but persistent limitation in elevation and depression on the right, and 10mm of residual proptosis. Review of the original orbital pathology failed to confirm malignancy and a repeat orbital biopsy was planned. PCR for IGH rearrangement done on the initial 2006 specimen demonstrated evidence of clonal immunoglobulin heavy chain gene rearrangement consistent with the presence of a clonal B-cell lymphoma. His entire picture was thus felt compatible with an extremely indolent low grade marginal B-cell lymphoma and plans were made for treatment with Rituximab. While ocular and adnexal lymphoma makes up only 1% of B-cell lymphomas it is the most common primary malignancy in the orbit. Flow cytometry and immunohistochemistry are usually adequate to make the diagnosis but when there is scarce lymphocytic infiltration and significant reactive expression the diagnosis may be difficult. PCR based gene rearrangement analysis offers an additional tool in identifying malignant involvement. When confined to the orbit these lesions may respond to local radiation therapy. Systemic involvement may occur at any time in 25 to 50%. As these lesions may disseminate years or even decades later continued surveillance is advised. Recent use of biologic agents expands our treatment armamentarium.