Abstract
Purpose:
DecisionDx-UM (Castle Bioscience, Phoenix, AZ) gene expression profiling (GEP) of uveal melanoma tissue obtained by fine needle aspiration biopsy is a frequently used prognostic test for the identification of patients at high risk for uveal melanoma metastasis. Benign melanocytic lesions are believed to provide a “Class 1”, or low-risk for metastasis designation. However, cytopathology is not typically obtained to confirm the actual lesion diagnosis. At some centers, performing GEP testing on indeterminate choroidal lesions may be used to direct a decision for treatment. We report our experience with uveal melanoma specific GEP testing on a series of choroidal metastatic tumors confirmed by cytopathology.
Methods:
Retrospective review of all cytopathology and DecisionDx-UM GEP reports between 2012 to 2014 from intraoperative fine needle aspiration biopsy (FNAB) of choroidal tumors undergoing brachytherapy at our center. Patient medical records including ancillary testing (fundus photography, fluorescein angiography, B-scan ultrasonography) were also reviewed.
Results:
Four patients (four eyes) were identified to have cytopathology consistent with a non-melanoma primary. All patients presented with a unilateral, single choroidal lesion. 50% of the patients were male. Mean patient age was 74.75 years (median 72.5 years, range 67-87 years). Two patients (50%) had a history of treated systemic cancer with no previous evidence of metastatic disease (one prostate, one lung). For the two patients with no history of systemic cancer, further systemic work-up revealed primary lung cancer in both cases. A GEP result was provided for each patient, three were Class 1A, one was Class 2.
Conclusions:
DecisionDx-UM GEP may be a helpful test to provide molecular prognostication in patients with uveal melanoma. However, because receiving both Class 1 and Class 2 test results are possible in the setting of a non-melanoma malignancy as we have demonstrated, we recommend that cytopathology and/or other melanoma-specific testing, (e.g. fluorescence in-situ hybradization for monosomy 3, GNAQ mutation analysis) also be performed. DecisionDx-UM GEP testing alone should be interpreted with caution in choroidal lesions which are not melanomas.