In our experience, trans-scleral fine needle aspiration biopsy (FNAB) does not provide sufficient tissue for all the required histological and genetic investigations, especially with thin tumours.TECHNIQUE:
The author has developed a simple technique for performing incisional choroidal tumour biopsy, immediately before ruthenium plaque insertion. Briefly, the tumour is localized by transillumination and its margins are marked on the sclera with a pen. A plastic plaque template is temporarily sutured to the sclera with releasable bows and its position checked by trans-scleral transillumination and binocular indirect ophthalmoscopy. After removing the template, a rectangular, lamellar scleral flap is made, which is hinged posteriorly. A small incision is made in the deep sclera and several tumour samples are obtained with Essen forceps. The flap is closed with tissue glue, without suturing. The ruthenium plaque is then sutured to the sclera, using the pre-placed sutures.DISCUSSION:
Tumor samples yielded using this method are larger than obtained with FNAB. The glue prevents tumour seeding into orbit and the lamellar flap protects the delicate ruthenium plaque surface from damage by the hardened glue.