Value of Positron Emission Tomography in the Diagnosis of Malignant Ocular Tumors

Abstract

PURPOSE: To address the question whether positron emission tomography (PET) can identify malignant ocular tumors. METHODS: In patients with ocular tumors, PET was performed using the incorporation of the glucose analogue (18)F-2-fluoro-2-deoxy-D-glucose. The diagnosis of the ocular lesions was based on conventional diagnostic procedures including histologic examination. RESULTS: Nineteen patients with a mean age of 62.8 +/- 14.2 years were included in this study. Nine patients with a mean age of 62.9 +/- 13.1 years displayed the presence of a malignant tumor including metastatic lesions (4), malignant melanomas (4) and squamous cell carcinoma (1). Additionally, 10 patients with a mean age of 62.8 +/- 15.9 years with benign lesions were studied. There was a statistically significant difference (p = 0.012) in tumor height and tumor volume, but not in tumor diameter between benign and malignant lesions. The smallest PET positive lesion measured 7 x 3 mm. PET was positive in 7 out of 9 malignant lesions and negative in all 10 benign lesions, i.e. there was no false-positive and two false-negative results. The two false-negative tumors represented malignant melanomas of the choroid. Additionally, results of the PET examination were independent of tumor size. CONCLUSION: PET seems to be of limited value for the diagnosis of malignant melanoma of the choroid, i.e. a negative result does not exclude a malignant process.