Posterior uveal biopsy and the trans-scleral Essen forceps biopsy technique

Abstract

Background: Differentiating neoplastic and non-neoplastic uveal tumours can present a diagnostic challenge; intra-ocular biopsy may be necessary. The novel trans-scleral Essen Forceps biopsy (TSEB) technique can improve diagnostic yield compared to fine needle aspiration biopsy (FNAB). We present a case demonstrating the technique and its added value. We also review the success rate of TSEB performed at two tertiary eye centres.

Methods: Retrospective case report and consecutive case series from August 2021 to March 2023. Inclusion criteria were patients who underwent TSEB of posterior uveal lesions from Moorfields Eye Hospital and Sheffield Teaching Hospitals in the United Kingdom. The outcomes were biopsy success rate and complication rate RESULTS: Eleven biopsies met the inclusion criteria. Eight (73%) were successful, which comprised six uveal melanomas, one melanocytoma and one extranodal marginal zone (ENMZ) lymphoma. One TSEB did not yield tissue for histological examination because of perioperative sample handling. Two (18%) biopsies were histologically inconclusive; both were treated as uveal melanoma on clinical grounds or repeat biopsy. The only complication was vitreous loss and retinal hole without retinal detachment in one eye with a very posterior, shallow choroidal lesion.

Conclusion: TSEB is an effective alternative to established biopsy techniques, yielding larger tissue samples than FNAB with intact tissue architecture. We recommend adding TSEB to the armamentarium of the ocular oncologist.

Fig. 1. Trans-scleral tumour biopsy with Essen forceps.

Following scleral exposure and marking of the tumour site, a fornix based partial thickness scleral flap is created (A) with the hinge over the thickest part of the tumour. Near the hinge of the flap, a 2-3 mm full thickness sclerostomy is created with a blade (B) giving access to the intraocular structures. The Essen forceps is passed into the lesion to be biopsied with the jaws open (C). The forceps are closed and the tissue sample remains within the jaws of the forceps (D). The tissue is placed on sterile card under the microscope to ensure the samples are safely retrieved (E). This process is repeated as often as necessary, sampling different parts of the lesion of interest each time. NB: for very thin lesions, the forceps should be passed along the inside of the sclera, parallel to the plane to avoid perforating retina. To minimise the chance of tumour cell seeding, the flap is closed by applying a small drop of cyanoacrylate glue (F). The flap is rapidly closed (G) with gentle pressure over the sclerostomy using a cotton bud. If needed, further glue can be applied to ensure full closure or 9-0 non-absorbable sutures can be pre-placed at the flap corners.

Fig. 2. Multimodal clinical imaging of the case described.

A Optos widefield fundal imaging at initial presentation with acute red eye. B Optos widefield fundal imaging three months after presentation following treatment with topical steroids. There was no regression in the choroidal lesion and subtle growth at the superior edge. C B-mode ultrasound of the choroidal mass at presentation, 2.1 mm (height) × 11.7 mm (longitudinal base) × 14.3 mm (transverse base), with low to medium echogenicity. There was a possible, slow internal blood flow as the recorded velocity in one vessel was 1.8 cm/s. D Histopathology of the specimen from the trans-vitreal biopsy of the right choroid which included tiny clumps of atypical cells. E Histopathology specimen obtained by Trans-scleral Essen Forceps biopsy (TSEB) of the right eye, stained with H & E at low magnification. This shows fibroconnective tissue with scattered melanin and an infiltrate of atypical cells with hyperchromatic nuclei, confirming malignant choroidal melanoma.

Fig. 3. Essen Biopsy Forceps, with shaft engraved depth indicator.

Developed by the Dutch Ophthalmic Research Centre and Department of Ophthalmology, University of Duisburg-Essen, Zuidland, The Netherlands [14]. Source: the Dutch Ophthalmic Research Center (D.O.R.C) Global Digital Marketing Manager, also available at [https://dorcglobal.com/product/akgul-biopsy-forceps-sharp-tip-23-gauge-06-mm]. License: Permission granted by D.O.R.C to use images for research purposes on 02/08/2022.