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Sampling of iris tumours. Sampling techniques. Broad iridectomy FNA Small gauge vitrector Kelly Descemet’s membrane Punch bx Technically difficult Requiring corneal sutures £. FNA experience. Hoovering a layer of cells from the surface with a bevelled needle
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Sampling techniques • Broad iridectomy • FNA • Small gauge vitrector • Kelly Descemet’s membrane • Punch bx Technically difficult Requiring corneal sutures £
FNA experience • Hoovering a layer of cells from the surface with a bevelled needle • 50% equivocal diagnosis-Why? • Low cellularity • Sampling of Vitamin C modified cells when in contact with aqueous and not deeper cells
Mudhar HS, Saunders E, Rundle P, Rennie IG, Sisley K. Br J Ophthalmol. 2009 Apr;93(4):535-40
New method: TC FCA • A clear corneal paracentesis (opposite the iris lesion being biopsied. • Viscoelastic introduced into the AC • A 25-guage Rycroft, or Viscoflow cannula attached to a 2 millilitre syringe and introduced in to the AC. • Negative pressure within the dry syringe, the cannula bevel passed repeatedly into the substance of the iris tumour. • This had the effect of creating what looked like a ‘phaco groove’ within the iris lesion
Method • The cannula and syringe transferred into a tube containing an alcohol based cytology fixative. • Repeated flushing of the Rycroft cannula to ensure all lesional tissue was transferred into the fixative • No corneal sutures required.
Complications: • Minor post bx haemorrhage day 1 post-bx.
Diagnostic outcomes • 10 MMs • 1 metastatic lung adenoca • 1 pigmented adenoma
Advantage: Cheap Quick Minimal complication No cornea sutures Samples deeper melanoma cells (unmodified by aqueous Vitamin C) allowing unequivocal diagnosis in MM cases. No ‘inadequate’ samples so far.
Anecdotal observation • VR surgeons had noticed quite often that cells in the vitreous tended to concentrate in the cortical vitreous and less in core vitreous.
WHY? • Cortical vitreous has different physicochemical properties to core vitreous….cells being trapped. • Cells near a source of oxygen (retina) and therefore likely to survive.
Literature • Documented false negative rate with core vitreous biopsy……often several biopsies needed before a positive diagnosis is made (lymphoma).
Test the idea of differential distribution of cells. • 5 patients • All patients were consented routinely for a core vitreous bx, followed by a PPV (pars plana vitrectomy) • Cytology-we received 2 specimens-Core bx and vitrectomy. • Cytopsins prepared.
Results • PPV specimen’s, 7.4 to 78 x cellular compared to core bx
Experience to date with complications: One case had peripheral retinal tear, with peripheral retinal fragments ending up in specimen. However, fortuitously, the fragments contained the diagnostic pathology (!).
Present practice: • Any vitreous infiltrate suspicious for lymphoma undergoes formal PPV with submission of vitreous cassette or bag to ophthalmic histopathology service. • Amount of tissue allows immuno and PCR for IgH, TCR, IL-6/IL-10 ratio etc.