Small Uveal Melanoma: Yield Rates and Other Traits of FNAB
JAMA Ophthalmology, May 2018
Assessing the adequacy of biopsy samples intraoperatively may help to ensure appropriate cell yield, which can be challenging for small lesions. In a retrospective study, Kim et al. documented yield rates for transscleral and transvitreal fine-needle aspiration biopsies (FNAB) of small uveal melanomas (apical height <3.6 mm); they found that intraoperative evaluation was associated with high yield and a favorable safety profile.
This observational study of consecutive cases included 44 patients (mean age, 63.3 years) with uveal melanoma of the ciliary body or choroid. In all cases, FNAB and intraoperative histopathologic analysis were performed before administration of iodine-125 (125I) brachytherapy. Tumor locations and dimensions were determined from B-scan ultrasonography and histopathologic analysis. Transscleral biopsy was performed for tumors anterior to the equator, and transvitreal biopsy was used for posterior lesions. The adequacy of each biopsy specimen was checked intraoperatively. Specimens underwent hematoxylin-eosin staining, double immunostaining with human melanoma black 45 and Ki67, and gene expression profiling.
The median tumor height was 2.7 mm (interquartile range, 2.3-2.9 mm). Of the 44 biopsy samples, 40 (90.9%) contained ample cells for gene expression analysis. Yield rates were 100% (11 of 11) for transscleral specimens and 87.9% (29 of 33) for transvitreal specimens.
Localized vitreous hemorrhages occurred in 24 eyes, and most resolved within 3 months. A moderate association was observed between localized vitreous hemorrhage and the transvitreal biopsy method (phi value, −0.526; p < .001).
As the role of genetic testing for uveal melanoma continues to expand, greater emphasis is being placed on obtaining specimens of adequate size. The authors’ findings suggest that intraoperative assessment helps ensure that samples contain a sufficient number of cells for analysis. Their research also affirms the safety and efficacy of FNAB as a diagnostic tool for uveal melanoma. Large prospective multicenter trials of various biopsy techniques are needed to determine the ones best suited for achieving high yield rates. The authors are participating in such an effort and plan to report their findings. (Also see related commentary by Carol L. Shields, MD, Arman Mashayekhi, MD, and Jerry A. Shields, MD, in the same issue.)
The original article can be found here.