Value of positron emission tomography in the diagnosis of malignant ocular tumors.

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.