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Original article
Intraocular biopsy using special forceps: a new instrument and refined surgical technique
  1. Harun Akgul1,
  2. Friedrich Otterbach2,
  3. Norbert Bornfeld1,
  4. Bernhard Jurklies1
  1. 1Department of Ophthalmology, Medical Faculty, University of Duisburg-Essen, Essen, Germany
  2. 2Institute of Pathology and Neuropathology, University of Duisburg-Essen, Essen, Germany
  1. Correspondence to Dr Harun Akgül, Department of Ophthalmology, University of Duisburg-Essen, Hufelandstraße 55, Essen 45147, Germany; harun.akguel{at}


Aim The aim was to investigate the Essen biopsy forceps as a new instrument and surgical approach for biopsy of intraocular tumours. Biopsy is indicated for assessment of any uncertain intraocular process or confirmation for presumed diagnosis before treatment. There is increasing interest for further genetic and immunocytological information in order to characterise the neoplasm, especially grading and prognosis of micrometastasis in uveal melanoma. The authors have developed a new surgical technique using special intraocular biopsy forceps.

Methods Twenty patients with uncertain intraocular subretinal tumour underwent biopsies carried out using the special Essen biopsy forceps. Biopsies were obtained through sutureless 23-gauge three-port vitrectomy. A small retinotomy tumour specimen was taken by the forceps branches. For further processing, the specimens were flushed out into a sterile tube and then sent to pathologists.

Results The prebioptical tumour had a mean thickness of 3.48 mm (1.1 to 9.8 mm). In all cases (n=20) biopsies (0.3–2.1 mm in size) were obtained, in 19 cases (95%) allowing precise histological and immunohistochemical typing of the lesions following cytoblock embedding. Uveal melanoma was diagnosed in 50% (n=10), choroidal metastasis in 15% (n=3) and choroidal naevus in 15% (n=3); other diagnoses (n=3) included choroidal haemangioma, B cell lymphoma and old subretinal haemorrhage. Apart from three patients with temporary punctual bleeding on the surface, there were no intra- and postoperative complications.

Conclusions Biopsy using special forceps is a promising new approach and precise surgical procedure. Especially for small intraocular tumours, this technique has the advantage in providing enough tissue for improved histological examination and presenting a low risk for complications.

  • Choroid
  • pathology
  • neoplasia
  • diagnostic tests/investigation
  • treatment surgery
  • forceps
  • intraocular biopsy
  • histology
  • uveal melanoma
  • intraocular tumour
  • ocular oncology

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Biopsy is indicated to confirm a diagnosis that is uncertain because of uncharacteristic clinical findings before treating an intraocular process. The use of non-invasive techniques to evaluate a suspected tumour and typical clinical aspects can lead to a false-positive or -negative diagnosis.1 Amelanotic lesions in particular are difficult to differentiate into uveal melanoma or metastasis, particularly in cases where there has not been a previous malignancy.2 3 Furthermore, biopsies are becoming more important because of the increasing interest in using genetic and immunocytological information to characterise the neoplasm, especially to grade the tumour and obtain a prognosis of micrometastasis in the case of uveal melanoma.4–7

Several surgical biopsy techniques using the transvitreal and trans-scleral pathway have been described in the literature, including fine-needle aspiration biopsy (FNAB).8–14 Incisional biopsy using a vitreous cutter through a standard three-port vitrectomy system has also been described.15–17 Despite extensive experience, especially with FNAB, there are still limitations on obtaining an adequate quantity of tissue in one procedure/puncture for histological, immunohistochemical and molecular analysis, particularly in small lesions.1 2 10 13

In collaboration with the Dutch Ophthalmic Research Center, we have developed a new instrument (a biopsy forceps) and a refined surgical technique for performing a biopsy of an intraocular mass. This makes it possible to obtain a larger tissue specimen from the region of interest at minimal expense and with a minimal risk of complications, and thus to make a highly accurate diagnosis. In addition, in the future it might become feasible to use these forceps in individual systemic adjuvant or neoadjuvant therapy for a malignant neoplasm.

Materials and methods

Although our biopsy forceps are a modified version of a standard CE-certified intraocular forceps, the instrument design is unique (23-gauge/0.6 mm). The essential modifications are to the inner grasping surfaces of the tip branches, making it possible to trap a sufficient sample (figure 1).

Figure 1

Essen biopsy forceps.

Intraocular biopsies were performed using these forceps in 20 patients with unclassifiable choroidal solid tumours.

After performing core vitrectomy using sutureless 23-gauge three-port vitrectomy (ALCON, Fort Worth, Texas) under general anaesthesia, posterior vitreous detachment was induced. After carefully determining the biopsy site (preferably a location of maximum tumour thickness) and avoiding retinal vessels, the intraocular pressure was elevated to 60 mm Hg to minimise potential tumour bleeding during the biopsy procedure. The transretinal entrance of the biopsy forceps was opened by making a 0.6 mm incision to the retina at the chosen biopsy site using a Sato knife (Storz Ophthalmics, St Louis, Missouri). The forceps were introduced into the tumour, and the specimen was obtained by visually controlled grasping. The enclosed specimen was carefully removed from the tumour by leading it through the vitreous cavity with the tip branches closed. The intraocular pressure was slowly decreased after prophylactic focal laser treatment of the retinotomy site. A fluid–gas exchange was not necessary.

The specimen was flushed out with isotonic saline solution into a sterile 1.5 ml Eppendorf tube and filled with 4% formalin or CytoLyt. It was then immediately submitted to the pathologist for further processing.

Specimen processing

After fixation for 6–24 h, the biopsy and tissue fragments were completely embedded in a gel button using the Shandon Cytoblock Cell Preparation System (Thermo Electron Company, Pittsburgh, Pennsylvania) according to the manufacturer's instructions. After standard dehydration, the gel buttons containing the tissue fragments were embedded in paraffin. To avoid tissue loss, 20 serial sections (3–5 μm thick) from each paraffin block were transferred to SuperFrost Plus slides (Menzel, Braunschweig, Germany). H&E stains of every fifth layer were reviewed for routine histological analysis and to choose the most representative level of the unstained slides for immunohistochemical analyses or special stains (figure 2). Up to 60 serial sections were necessary in some cases to find the level of interest.

Figure 2

Uveal melanoma showing polymorphous atypical melanocytes and pigmented melanophages.


The mean tumour height prior to biopsy was 3.48 mm (1.1 mm to 9.8 mm). The tumours were mainly non-pigmented or partially pigmented (n=14). In all cases (n=20), 0.3–2.1 mm large biopsies were obtained. In 17 cases (85%), the biopsy material was detected on the histological slides with the maximum diameters ranging from 0.05 to 1.7 mm. Tissue fragmentation and loss were preferentially observed in the CytoLyt-fixed specimens. Cellular material was present in 11 of 20 ThinPrep cytospins. Based on the combined histological and cytological approach, the diagnosis of malignant melanoma was made in 10 (50%) cases. There were three cases of metastatic carcinoma and one case of non-large-cell B-lymphoma. Malignancy was thus demonstrated in 14 (70%) cases overall. No malignancy was found in five (25%) cases of melanocytic lesions without obvious atypia including choroidal naevus (n=3), haemangioma (n=1) and sclerosis (n=1). In 19 cases (95%), a precise diagnosis was achieved on the basis of the clinical findings and the histological/immunohistochemical typing of the lesions following cytoblock embedding (table 1). In one case, the diagnosis was uncertain because of an uninformative specimen. Aside from three patients with temporary punctual bleeding on the surface, there were no intra- or postoperative complications.

Table 1

Patients and biopsy results

Two exemplary cases

Case 1

A previously healthy 80-year-old male patient presented with a small subretinal tumour in the left eye without any visual symptoms. The tumour was detected during a routine ophthalmological examination for cataract surgery. Ophthalmoscopy revealed a melanotic, well-defined choroidal tumour 7.6 mm in diameter and 2 mm thickness in the inferotemporal quadrant next to the inferotemporal arcade without any orange pigment or retinal detachment (figure 3).

Figure 3

Case 1: (A) pre- and (B) postoperative ophthalmoscopy.

Histopathological examination of the specimen revealed malignant uveal melanoma of the spindle cell type B. After this diagnosis, the patient was immediately treated by ruthenium plaque brachytherapy.

Case 2

A 47-year-old woman presented without any history of malignancy and any ophthalmological symptoms. A complete systemic screening evaluation had been performed for suspected uveal metastasis before the woman came to our clinic. An oncologist had not found a primary neoplasm or any suspicious metastatic lesions.

Ophthalmoscopy revealed a parapapillary choroidal tumour in the inferior quadrant that was mainly melanotic in nature. It was 10–11 mm in diameter and 2.5 mm thickness. Retinal fluid was the only pathological manifestation (figure 4).

Figure 4

Case 2: (A) pre- and (B) postoperative ophthalmoscopy.

The suspected metastasis was not confirmed. The histopathological and immunohistochemical analyses revealed a melanocytic naevus without any signs of malignancy. Ophthalmic follow-up examinations have so far been negative, and no changes in morphology or size of the lesion have been noted.

In both cases, there were no intra- and postoperative complications other than vitreous haemorrhage or retinal detachment in a 6-month follow-up period.


Our newly developed biopsy forceps represent a safe and precise approach to performing intraocular biopsy. The advantage of this technique, especially for solid and small tumours, is that it obtains enough tissue for a combined histological and immunohistochemical examination with minimal risk of complications. Other procedures, in contrast, support a ‘cell suspension’ by FNAB for cytological and immunocytological examination. The 23-gauge size of the biopsy forceps makes it possible for a less traumatic sutureless operation procedure known as the 23-gauge three-port vitrectomy system to be performed. This surgical technique was employed under general anaesthesia, but it can also be performed under local anaesthesia, depending on the patient's general state of health and preference.

The risk of complications with this method is the same as that for vitreoretinal surgery in general. The theoretical risk of intraocular tumour dissemination should be considered in follow-up examinations.15 In particular, samples with diameters >0.6 mm can stick in the entry site by crossing the 23-gauge trocar. The fluid flow during the vitrectomy procedure minimises the risk of seeding tumour material, which has not been detected in our series so far. The significance of tumour cell seeding in connection with this transvitreal approach is expected to be as low as that described for other transvitreal approaches.1 18 The biopsy cases have to be followed up and evaluated by further prospective studies.

The biopsy forceps represent a new promising approach for precise and controlled intraocular biopsy. Its advantage is in obtaining a specimen that permits a high diagnostic accuracy.

However, the success of this new method depends greatly on a thorough work-up and examination of the minute specimen by well-trained technicians and pathologists.



  • Competing interests None.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.