Value of positron emission tomography/computed tomography in diagnosis and staging of primary ocular and orbital tumors

Abstract

Accurate and reliable staging methods are crucial for optimal care of patients with ocular and orbital malignancies. Positron emission tomography/computed tomography (PET/CT) has recently emerged as a staging tool in the field of ophthalmic oncology. For detecting primary ocular or orbital lesions, PET/CT does not seem to provide an advantage over clinical ophthalmologic examination or conventional imaging studies such as CT or magnetic resonance imaging of the orbit. However, PET/CT may detect distant metastatic lesions that conventional imaging studies miss. For orbital and ocular adnexal lymphoma, use of PET/CT has been proven to be feasible and is now accepted both as a standard part of the initial staging work-up and for the assessment of response to therapy. For other ophthalmic tumors, PET/CT seems most appropriate for advanced metastatic tumors of the orbit, eyelid, and eye, for which the detection of distant metastasis with 1 comprehensive study may be preferable to performing multiple CT scans with contrast.

Keywords: Cancer staging; MALT lymphoma; Orbital lymphoma; Orbital tumors; Positron emission tomography/computed tomography; Uveal melanoma.

Figure 1

Baseline PET in a patient with lacrimal gland MALT lymphoma shows a focal area of increased FDB uptake in the right arm. An MRI of the upper extremity was subsequently done and confirmed the presence of a lesion in the biceps muscle which upon biopsy proved to be a focus of lymphoma.

Figure 2

PET/CT findings in a patient with Merkel cell carcinoma of the eyelid. (A) FDG uptake in the upper eyelid. (B) FDG uptake in the parotid nodal basin. The patient also had a palpable mass in the parotid. PET/CT was ordered to rule out other sites of distant metastasis.