A Woman With Progressive Double Vision and Proptosis

C. Robert Bernardino, MD

Disclosures

February 15, 2013

Diagnostic Workup

Imaging Studies

To help determine etiology, imaging studies of the orbit are essential. CT or MRI would image the orbit well. In this case, CT was performed (Figure 2), which demonstrated a mass encasing the optic nerve. The mass is poorly defined and does not have any apparent calcifications.

Figure 2. An axial CT soft tissue window demonstrates a mass encircling the optic nerve from the globe to the apex. It does not distort the shape of the globe and no calcifications are present.

Tumors that surround or involve the optic nerve with this appearance include optic nerve meningioma, orbital inflammatory pseudotumor, and lymphoid tumors. Optic nerve sheath meningiomas typically have a tram-track appearance, focal areas of calcification, and well-defined borders. Orbital inflammatory pseudotumor tends to be poorly defined with areas of enhancement correlating with inflammation. Clinically, these cases usually present with sudden onset of pain and are less often indolent. Lymphoid tumors tend to have a fairly homogeneous appearance, with the tumor molding around other orbital structures such as bone or the globe. The CT scan was not definitive for any of the 3 diagnoses.

Tissue Biopsy

Because the diagnosis was not definitive, a tissue biopsy was offered. Approaches to the optic nerve include a transconjunctival approach, in which one of the rectus muscles is detached from the globe and dissection is carried between the muscle and the globe to gain access to the intraconal space and the optic nerve. An alternative approach is the supramedial eyelid crease incision, which allows for access to the intraconal space and optic nerve without detaching the rectus muscles. In this case, a transconjunctival approach was taken with detachment of the medial rectus muscle. Specimens were sent for frozen section analysis, and the preliminary diagnosis was lymphoma.

Comment

This case demonstrated a slowly progressive optic nerve tumor that caused proptosis and other orbital signs. In many cases of unilateral proptosis, imaging studies are definitive. For example, in cases of optic nerve sheath meningiomas, treatment such as radiation can be offered without a tissue diagnosis. In this case, imaging was not conclusive, so a biopsy was performed.

Orbital lymphoma may present as the primary lesion or as a lesion in conjunction with systemic involvement. Treatment depends on systemic involvement; therefore, the presence of distant lesions is determined with body imaging using CT or PET scans. In addition, bone marrow biopsy may be helpful. In cases of isolated lymphoma to the orbit, orbital radiation is often sufficient, whereas systemic involvement requires chemotherapy.

Suggested Reading

Savino PJ. Isolated optic nerve lymphoma diagnosed by optic nerve biopsy. Am J Ophthalmol. 2005;139:1128-1130.

Yadav BS, Sharma SC. Orbital lymphoma: role of radiation. Indian J Ophthalmol. 2009; 57:91-97.

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