PATHOLOGY Intraocular collision tumour: case report and literature review Sarah E. Coupland & Andrew Dodson & Hongxiang Liu & Ming-Qing Du & Martina Angi & Bertil E. Damato Received: 27 September 2012 / Revised: 13 November 2012 / Accepted: 19 November 2012 # Springer-Verlag Berlin Heidelberg 2012 Abstract Background “Collision” tumours consist of different neo- plasms coexisting within a single lesion. Whilst quite com- mon in the skin, the gastrointestional tract, and the ovaries, intraocular collision tumours are exceedingly rare. We de- scribe an exceptional case of a combined uveal melanoma and intraocular plasmacytoma. Methods Observational case report. A 61-year-old woman underwent enucleation for rubeotic glaucoma and cells in the anterior chamber after proton-beam radiotherapy of a cilio- choroidal melanoma of the right eye. Examination of the enucleated eye was performed with immunohistochemistry, multiplex ligation dependent probe amplification (MLPA), and polymerase chain reaction (PCR) for immunoglobulin heavy- and light-chain gene rearrangements. A review of the literature on ocular collision tumours and uveal involvement by plasma cell neoplasms was also performed. Results Morphological, immunophenotypical, and genotyp- ical examination of the tumour revealed the co-existence of both a melanoma and a plasmacytoma within the choroid and ciliary body. The glaucoma was caused by extensive infiltration of the iris and trabecular meshwork by the plas- macytoma cells. Review of the literature revealed only four collision tumours involving the eyelid and three involving the choroid. All three intraocular collision tumours con- sisted of uveal melanoma and choroidal non-Hodgkin lym- phoma. Uveal involvement by plasma cell neoplasms is also extremely rare, with only six reported cases. Conclusions This is the first documented intraocular colli- sion tumour consisting of a uveal melanoma and isolated plasmacytoma. If a patient presents with ‘uveitis’ after proton-beam radiotherapy of a cilio-choroidal melanoma, there may be scope for performing biopsies to determine whether the lymphoid infiltrate is reactive or neoplastic. Keywords Collision tumour . Choroidal melanoma . Ciliary body extramedullary plasmacytoma Introduction “Collision” tumours consist of different neoplasms coexist- ing within a single lesion, either because two different types of cancer have independently and metachronously arisen at the same place, or because one or both malignancies have metastasized to the same location [1]. They must be differ- entiated from “composite” tumours, which consist of a malignant neoplasm that has differentiated into two distinct subtypes. Numerous collision tumours have been reported, Electronic supplementary material The online version of this article (doi:10.1007/s00417-012-2216-0) contains supplementary material, which is available to authorized users. None of the authors has any financial relationship to disclose. The authors have full control of all primary data, and they agree to allow Graefe’ s Archive for Clinical and Experimental Ophthalmology to review their data if requested. S. E. Coupland (*) : A. Dodson : M. Angi Department of Molecular and Clinical Cancer Medicine, University of Liverpool, 5th Floor Duncan Building, Daulby Street, Liverpool L69 3GA, UK e-mail: s.e.coupland@liverpool.ac.uk H. Liu Molecular Malignancy Laboratory and Department of Histopathology, Addenbrooke’ s Hospital, Cambridge Hospitals NHS Foundation Trust, Cambridge, UK M.-Q. Du Department of Pathology, University of Cambridge, Cambridge, UK B. E. Damato Liverpool Ocular Oncology Centre, Royal Liverpool University Hospital, Liverpool, UK Graefes Arch Clin Exp Ophthalmol DOI 10.1007/s00417-012-2216-0