The Pediatric and Young Adult Choroidal and Ciliary Body Melanoma Genetic Study, A Survey by the European Ophthalmic Oncology Group.

Purpose: To explore the genetic background of choroidal and ciliary body melanoma among children and young adults, with special focus on BAP1 germline variants in this age group. Methods: Patients under the age of 25 and with confirmed choroidal or ciliary body melanoma were included in this retrospective, multicenter observational study. Nuclear BAP1 immunopositivity was used to evaluate the presence of functional BAP1 in the tumor. Next-generation sequencing using Ion Torrent platform was used to determine pathogenic variants of BAP1, EIF1AX, SF3B1, GNAQ and GNA11 and chromosome 3 status in the tumor or in DNA extracted from blood or saliva. Survival was analyzed using Kaplan-Meier estimates. Results: The mean age at diagnosis was 17 years (range 5.0-24.8). A germline BAP1 pathogenic variant was identified in an 18-year-old patient, and a somatic variant, based mainly on immunohistochemistry, in 13 (42%) of 31 available specimens. One tumor had a somatic SF3B1 pathogenic variant. Disomy 3 and the absence of a BAP1 pathogenic variant in the tumor predicted the longest metastasis-free survival. Males showed longer metastasis-free survival than females (P = 0.018). Conclusions: We did not find a stronger-than-average BAP1 germline predisposition for choroidal and ciliary body melanoma among children and young adults compared to adults. Males had a more favorable survival and disomy 3, and the absence of a BAP1 mutation in the tumor tissue predicted the most favorable metastasis-free survival. A BAP1 germline pathogenic variant was identified in one patient (1%), and a somatic variant based mainly on immunohistochemistry in 13 (42%).

Ocular Metastasis as First Presentation of Large-Cell Neuroendocrine Carcinoma.

Introduction: We report a rare case of an aggressive large-cell neuroendocrine lung tumour, which presented with ocular metastasis. Case Presentation: A 70-year-old lady presented with a 4-week history of left eye pain and photophobia. Ocular examination revealed left-sided episcleritis and she was treated with topical lubricants and steroids. However, she re-presented 6 months later with recurrent left eye symptoms and was found to have an iris stroma amelanotic lesion, posterior synechiae, 360-degrees rubeosis iridis, raised intraocular pressure, and trace vitreous inflammation. Ultrasound biomicroscopy revealed a left thickened iris with an associated ciliary body lesion. Sarcoid-related ocular inflammation was suspected, but a computed tomography (CT) scan of the lung revealed an incidental right upper lobe lesion. Histology from a transcorneal iris biopsy showed a high-grade neuroendocrine carcinoma, and the diagnosis of metastatic lung large-cell neuroendocrine carcinoma was confirmed via high-resolution CT scan, positron emission tomography scan, and CT-guided lung biopsy. She was given multiple courses of different chemotherapy regimens along with palliative radiotherapy. However, the tumour and its metastases continued to progress and she passed away 4 years after her initial presentation. Conclusion: Ocular metastatic large-cell neuroendocrine carcinoma is rare, and the first presentation with ocular metastasis is even rarer. This case highlights the importance of early detection of ocular metastases in order to hasten oncological treatment. A low threshold for systemic investigations and ophthalmology referral in cases of unexplained, refractory ocular symptomatology is essential, given the heterogeneous presentation, rarity, and poor prognosis of these tumours, even with maximal treatment.

PRAME expression by immunohistochemistry and reverse transcription quantitative PCR in conjunctival melanocytic lesions-a comprehensive clinicopathologic study of 202 cases and correlation of cytogenetics with PRAME expression in challenging conjunctival melanocytic lesions.

This study examined PRAME (preferentially expressed antigen in melanoma) expression by immunohistochemistry and reverse transcription quantitative PCR (RT-qPCR) in 202 histologically unequivocal conjunctival melanocytic lesions: 76 nevi, 29 benign melanoses, 25 low-grade conjunctival intraepithelial melanocytic lesions (LGCMIL), 26 high-grade conjunctival melanocytic intraepithelial lesions/in-situ melanoma (HGCMIL), and 46 invasive melanomas. PRAME score 0 was seen in 96% of nevi (73/76), 96% of benign melanoses (28/29), and 88% of LGCMIL (22/25). PRAME score 4 was seen in 50% HGCMIL (13/26) and 76% invasive melanomas (35/46). PRAME score 4 had a sensitivity of 50% and specificity of 100% in differentiating between HGCMIL and benign melanosis/LGCMIL. PRAME score 4 had a sensitivity of 76% and specificity of 100% in differentiating between melanoma and nevi. Relative quantification of PRAME mRNA expression by RT-qPCR was performed on 49 cases (24%): 17 nevi, 3 benign melanoses, 5 LGCMIL, 9 HGCMIL, and 15 invasive melanomas. The analysis generated two distinct groupings with 'high' relative PRAME expression for the HGCMIL and invasive melanoma and 'low/zero' expression for nevi, benign melanosis, and LGCMIL. Thirty-three challenging conjunctival melanocytic lesions that had previous fluorescence in situ hybridization (FISH) analysis were studied: 18 nevi, 12 melanomas in a nevus, 2 nevoid melanomas, and 1 in-situ melanoma. All nevi (100%) showed concordance between negative FISH and PRAME (scores 0-3). Four of 13 melanomas (31%; in-situ, invasive, isolated, and in association with nevus) showed concordance between positive FISH and PRAME score 4. In conclusion, PRAME score 4 has 100% specificity for the diagnosis of HGCMIL and melanoma. PRAME is limited in its sensitivity in the evaluation of challenging melanocytic lesions.

Consensus statement for metastatic surveillance of uveal melanoma in Scotland.

Ophthalmic treatments are successful in managing uveal melanomas achieving good local control. However, a large number still metastasise, primarily to the liver, resulting in mortality. There is no consensus across the world on the mode, frequency, duration or utility of regular liver surveillance for metastasis and there are no published protocols. The Scottish Ocular Oncology Service (SOOS) constituted a Scottish Consensus Statement Group (SCSG) which included ocular oncologists, medical oncologists, radiologists and a uveal melanoma patient as a lay member. This group carried out an extensive review of literature followed by discussions to arrive at a consensus regarding surveillance planning for posterior uveal melanoma patients in Scotland. The Consensus Statement would provide a framework to guide each patient's surveillance plan and provide all patients with clarity and transparency on the issue. The SCSG was unable to find adequate evidence on which to base the strategy. The consensus statement recommends a risk-stratified approach to surveillance for these patients dividing them into low to medium-risk and high-risk groups defining the mode and duration of surveillance for each. It supplements the UK-wide Uveal Melanoma National Guidelines and allows a more uniform consensus-based approach to surveillance in Scotland. It has been adopted nationally by all health care providers in Scotland as a guideline and is available to patients on a publicly accessible website.

Incidence and survival of uveal melanoma in Northern Ireland: how incomplete data can skew results in rare cancers.

BACKGROUND: The majority of Northern Irish uveal melanoma (UM) patients are diagnosed in Sheffield. This study aims to present incidence and survival outcomes for UM patients from Northern Ireland (NI). METHODS: Collaborative retrospective study between Sheffield and Northern Ireland Cancer Registry (NICR). For UM cases not on both databases, outcomes and survival rates (via Kaplan-Meier analysis) were compared. Anonymised NICR data were used to calculate whole-population incidence of UM for NI. RESULTS: In total, 161 patients from NI were diagnosed in Sheffield, 90 of which were not registered with NICR at the start of this study. Data-omissions were not consistent across patient groups, leading to significant differences between those patients registered and those not. Registered patients had an all-cause 5-year survival rate of only 68.9% compared to 92.5% of those not registered (p < 0.01) and were >17x more likely to have systemic metastases than those not registered (p < 0·001). Following rectification of data-omissions, the European age-standardised incidence rate of UM for NI was 8·6 per million. CONCLUSIONS: This study illustrates the impact of incomplete population-wide data, serving as a real-world lesson in case-identification bias. Rare cancers are at higher risk of omission due to systemic failures as the small numbers involved are not detected by system-wide validation procedures. Following this study, data-transfer agreements between England and NI were actioned, preventing future data-omissions. We present survival and incidence data for UM in NI for the first time, showing the incidence is amongst the highest in Europe, with good survival rates.

Lacrimal sac ciliated HPV16 positive, adenosquamous carcinoma-A case report of a unique histological variant at this site and a review of the literature.

A 47-year-old female developed a reddish swelling of the right medial canthus over 3 months. On examination, a red, firm mass, involving the right medial canthal and extending into the inferior fornix was present and the globe was displaced upwards and inwards. A staging MRI scan confirmed a lacrimal sac lesion with anterior orbit extension. After an equivocal biopsy, the patient underwent debulking surgery. Histology showed a lacrimal sac invasive adenosquamous carcinoma, comprising poorly differentiated squamous carcinoma and invasive adenocarcinoma areas arranged in a tubulo-glandular pattern. The adenocarcinoma harboured numerous cilia. p16 showed block positivity of both components and micro-dissected tissue from both areas showed the presence of HPV16 DNA by PCR. This is the first description of ciliated adenosquamous carcinoma of the lacrimal sac and this finding is placed into the context of what is known about ciliated head and neck adenosquamous carcinomas and the role of high-risk HPV.

Single Time Frame Overview of the Genetic Changes in Conjunctival Melanoma from Intraepithelial Disease to Invasive Melanoma: A Study of 4 Exenteration Specimens Illustrating the Potential Role of Cyclin D1.

Introduction: Despite advances in the understanding of the molecular pathogenesis of cutaneous melanoma, relatively little is known about the genetic changes that occur in the progression of conjunctival melanocytic intraepithelial lesions to invasive conjunctival melanoma. Methods: We exposed 4 exenteration specimens that each contained varying grades of intraepithelial conjunctival melanocytic neoplasia and invasive neoplasia to a combination of various techniques, including array comparative genomic hybridization (aCGH), ribonucleic acid sequencing (RNA-seq), fluorescence in situ hybridization (FISH), and immunohistochemistry. Results: Three out of 4 of the invasive melanomas showed gains in 11q13 (CCND1 locus) by aCGH. FISH demonstrated CCND1 gain in invasive melanoma and in conjunctival melanocytic intraepithelial lesions (CMILs) of all grades (low-grade CMILs and in situ melanoma), and this was paralleled by increased expression of Cyclin D1 protein within the atypical melanocytes by immunohistochemistry, using a double-staining method with a red end point for Melan A cytoplasmic staining and a brown end point for nuclear Cyclin D1 expression. Higher grades of melanocytic intraepithelial lesions showed more cells expressing Cyclin D1 than lower grade melanocytic intraepithelial lesions. The Cyclin D1 protein expression was in the same location as the amplified CCND1 signal by FISH. One out of 3 of these cases also showed the amplification of the 12q13-15 locus corresponding to MDM2 and FISH confirmed gains in the conjunctival melanocytic intraepithelial neoplasia and invasive melanoma. The remaining fourth case showed a homozygous deletion of 9p21 (CDKN2A) by aCGH only, with immunohistochemistry showing clonal loss of p16 protein expression in the invasive and conjunctival melanocytic intraepithelial lesion. Two out of 4 of the invasive melanomas harboured classical driver mutations in NRAS and NF-1, respectively. None of the cases showed mutations in BRAF, KIT, and TERT mutations. RNA-seq data showed secondary mutations in ARAF, PLCB4, MET, EZH2, MAP2K2, CTNNB1, CIITA, NF2, TP53, and MEN1, some of which are implicated in the MAPK pathway. Conclusion: CMILs harbour amplifications of CCND1 (3 cases), MDM2 (1 case), and loss of CDKN2A (1 case), which are also present when the lesion progresses to invasive melanoma, implicating these amplifications in the early pathogenesis of CMILs. This study represents the first attempt to capture the mutational landscape of all stages of conjunctival melanoma in a single tissue excision.

Fibrin glue assisted amniotic membrane graft reconstruction of conjunctival fornix and canthus following excision of conjunctival tumours.

Conjunctival tumors involving non-limbal locations, such as the fornix and canthus, are typically excised using a "non-touch" technique, often with a wide surgical margin. Reconstruction of these large defects can be difficult due to the contour of the ocular surface and are often complicated by shortening of the fornix, symblepharon formation, and restriction of eye movements. In our experience, the use of amniotic membrane grafts combined with the sealant properties of fibrin glue such as Tisseel® has improved our surgical outcomes during the reconstruction phase. We would like to highlight and describe our surgical technique using fibrin glue and squint hooks to aid amniotic membrane graft reconstruction for surgically challenging locations in the fornix and canthus following excision of conjunctival lesions, with excellent surgical outcomes.

To suture or not to suture? Does globe immobilisation technique affect clinical outcome in stereotactic radiosurgery for uveal melanoma?

INTRODUCTION: Stereotactic radiosurgery (SRS) is a valuable treatment option for uveal melanoma, offering excellent tumour control rates and eye preservation. Its efficacy relies upon accurate localisation of the tumour, which is challenging in the mobile eye. Various methods of globe immobilisation have been used, including non-invasive devices, such as eye movement tracking and suction cups, but common practice is to use local anaesthetic block with or without transconjunctival suturing of the extraocular muscles. Some studies have suggested that the addition of muscle suturing to local anaesthetic block provides better immobilisation of the globe, when compared to anaesthetic block alone. Controversy exists regarding the clinical relevance of this observation and ocular oncologists differ in their choice of immobilisation technique. METHODS: In order to establish if the addition of muscle suturing to local anaesthetic block improves clinical outcomes, we performed a retrospective review of all cases that underwent SRS for uveal melanoma over a 10-year period (May 2008 to May 2018). Based on surgeon preference, all patients received either local anaesthetic block plus muscle suturing (Group A) or local anaesthetic block alone (Group B) to induce globe akinesia. Outcomes assessed were primary treatment failure, tumour recurrence, secondary enucleation and death rate. RESULTS: In our cohort of 290 eyes; 118 patients were in group A and 172 patients were in group B. There were no cases of primary treatment failure in either group. With a minimum of 24 months follow-up, only 3 patients experienced tumour recurrence (1 in group A and 2 in group B). There was no significant difference in recurrence, enucleation and all-cause death rates between the two groups. CONCLUSION: Our retrospective review suggests that although extraocular muscle suturing may be considered by some units to provide superior globe immobilisation for SRS, it does not alter the clinical outcome.

Gamma Knife Stereotactic Radiosurgery for Conjunctival Squamous Cell Carcinoma Invading the Anterior Orbit: A Case Series.

INTRODUCTION: The aim of the study was to report our experience in the use of Gamma Knife Stereotactic Radiosurgery (GKSTRS) for conjunctival squamous cell carcinoma (SCC) invading the orbit, as an alternative to exenteration surgery. PATIENTS AND METHODS: Patients who had GKSTRS for conjunctival SCC invading the orbit but sparing the bone (AJCC eighth ed. T4a) with a minimum of 1-year follow-up were included. Treatment failure was defined as no decrease in tumour size 3 months post-treatment, or further growth during the follow-up period. Patients were followed up 3-monthly for 2 years and 6-monthly afterwards with a minimum of yearly MR Imaging of orbit. RESULTS: Six patients met the inclusion criteria. MR imaging was used to identify the extent of orbital involvement of SCC. Stereotactic radiosurgery utilizing the Leksell Gamma Knife® Perfexion was delivered in a single session in which patients received 18-20 Gy to the 45-50% isodose. The median follow-up was 29 months. Four patients responded to the treatment and had no evidence of recurrence at their most recent follow-up. The treatment failed in 2 patients, in 1 of whom the tumour was larger and extended deeper into the orbit. The other patient developed a recurrence away from the treated area at 9 months, suggesting a multifocal disease. Both patients had poorly differentiated SCC. CONCLUSION: GKSTRS is a potential alternative to orbital exenteration surgery for conjunctival SCC extending into the anterior orbit in a selected group of patients refusing orbital exenteration or has a second blind eye. Nevertheless, the disease is more likely to recur than with exenteration surgery, hence lifelong monitoring and low threshold for surgical intervention or retreatment is prudent.

Choroidal Metastasis Secondary to Testicular Mature Teratoma: A Case Report.

We report a case of a choroidal metastasis secondary to testicular mature teratoma, a subtype of non-seminoma germ cell tumours, in a young adult male. The choroidal metastasis was treated successfully with bleomycin, etoposide, and cisplatin chemotherapy without the need for adjuvant radiotherapy. This represents a rare case of mature teratoma metastasizing to the choroid and one of very few reported testicular germ cell tumours to achieve normal or near normal visual acuity with chemotherapy alone despite severe macular disease at presentation.

Computerized Tomography-Guided Core-Needle Biopsy of Orbital Space-Occupying Lesions: A Case Series.

PURPOSE: To describe our experience in performing biopsy of post-septal orbital masses with core needle under computerized tomography guidance (CT-CNB). METHODS: The medical records of all patients who underwent this procedure were reviewed. The procedure was performed under local anesthesia on a day case basis under a peribulbar block. A planning non-contrast computerized tomography (CT) scan of the orbits was performed to localise the mass. A 6-cm 18-G Temno Evolution® semi-automated biopsy needle was inserted through the skin into the orbit. Prior to further advancement of the needle, a low-dose CT limited to the previously determined plane was performed to confirm its position. The needle was then advanced, and the cutting needle was deployed to obtain the biopsy. RESULTS: Five patients who underwent CT-CNB were identified. The CNB was successful in 4 patients and revealed a metastatic prostate adenocarcinoma, diffuse large B-cell lymphoma, a metastatic neuroendocrine tumour, and orbital inflammatory disease. The biopsy failed in the fifth patient when the needle failed to penetrate the tumour despite good localisation on CT. He was eventually diagnosed with fibrous meningioma of the greater wing of sphenoid on open biopsy. None of the patients had any complications other than peri-ocular bruising which was present in all of them. CONCLUSION: CT-CNB of mass lesions located in the lateral aspect of the orbit can be an alternative to open biopsy in selected cases. It avoids major surgery and allows the use of radiotherapy, if required, without any delay.

Systemic acitretin in the management of periocular squamous cell carcinoma.

We report a case of periocular squamous cell carcinoma invading the anterior orbit that significantly reduced in size and regressed from invasive to in situ following treatment with oral acitretin, a second-generation retinoid. The residual in situ disease was then successfully treated with cryotherapy and the patient remains in remission 12 months following cessation of systemic acitretin.

Impact of COVID-19 pandemic on eye cancer care in United Kingdom.

The COVID-19 pandemic has had an unprecedented impact on the National Health Service in United Kingdom. The UK Ocular Oncology Services evaluated the impact on the adult eye cancer care in the UK. All four adult Ocular Oncology centres participated in a multicentre retrospective review comparing uveal melanoma referral patterns and treatments in a 4-month period during the national lockdown and first wave of the COVID-19 pandemic in 2020 with corresponding periods in previous 2 years. During the national lockdown, referral numbers and confirmed uveal melanoma cases reduced considerably, equalling to ~120 fewer diagnosed uveal melanoma cases compared to previous 2 years. Contrary to the recent trend, increased caseloads of enucleation and stereotactic radiosurgery (p > 0.05), in comparison to fewer proton beam therapy (p < 0.05), were performed. In the 4-month period following lockdown, there was a surge in clinical activities with more advanced diseases (p < 0.05) presenting to the services. As the COVID-19 pandemic continues to mount pressure and reveal its hidden impact on the eye cancer care, it is imperative for the Ocular Oncology Services to plan recovery strategies and innovative ways of working.

Uveal Melanoma and Paraneoplastic Perivascular Dermal Melanocytic Proliferation in the Setting of Bilateral Diffuse Uveal Melanocytic Proliferation: The Potential Role of the Hepatocyte Growth Factor/c-Met Axis in Their Pathogenesis.

Two patients, with non-small cell lung carcinoma treated with pembrolizumab, developed bilateral diffuse uveal melanocytic proliferation (BDUMP) with interesting histopathological features. The first patient developed a right ciliary body mass concurrently with BDUMP. The globe was enucleated. The ciliary body mass was a mitotically active epithelioid uveal melanoma, invading the trabecular meshwork and peripheral corneal stroma, with over 90% of the cells expressing Cyclin D1 protein. The melanoma showed no chromosome 3 or 8 changes. The background uvea showed diffuse, bland spindle cell melanocytic proliferation with much lower Cyclin D1 expression (around 10%). In the choroid, this population was punctuated by islands of pigmented epithelioid cells, some of which were necrotic. All these islands expressed a high level of Cyclin D1, and some islands expressed nuclear preferentially expressed antigen in melanoma (PRAME). The ciliary body mass, epithelioid cell islands, and the BDUMP all expressed c-Met (the receptor for hepatocyte growth factor [HGF]). The features were those of ciliary body melanoma and choroidal melanoma "tumorlets," developing on a background of BDUMP. The second patient developed bilateral periocular skin pigmentation following a diagnosis of BDUMP, which when biopsied, showed dermal islands of paraneoplastic perivascular melanocytic cell proliferation. These cells also expressed c-Met protein. These observations implicate the HGF/c-Met axis in the pathogenesis of BDUMP, the uveal melanomas in the ciliary body and choroid in the first patient and the paraneoplastic dermal melanocytic proliferation in the second patient.

Usefulness of PAX8 Immunohistochemistry in Adult Intraocular Tumor Diagnosis.

PURPOSE: To evaluate the distribution of the PAX8 transcription factor protein in ocular tissues and to investigate if immunohistochemical stains for this biomarker are useful in the diagnosis of intraocular tumors. DESIGN: Observational case series. PARTICIPANTS: Excision and cytologic analysis specimens of 6 ciliary body epithelial neoplasms, 2 iris epithelial neoplasms, 3 retinal pigment epithelial neoplasms, 3 intraocular medulloepitheliomas, 15 uveal melanomas, and 5 uveal melanocytomas. METHODS: Hematoxylin-eosin and PAX8 immunohistochemical stains were performed on all specimens. In appropriate cases, bleached preparations and other immunohistochemical stains, including AE1/AE3 cytokeratin, Lin28A, and CD45, were performed. MAIN OUTCOME MEASURES: Distribution of PAX8 expression in normal and neoplastic tissue. RESULTS: Strong nuclear PAX8 expression was observed in the normal corneal epithelium, iris sphincter pupillae muscle, iris pigment epithelium and dilator muscle complex, nonpigmented and pigmented epithelia of the ciliary body, lens epithelium, and a subset of retinal neurons. The normal retinal pigment epithelium and uveal melanocytes did not stain for PAX8. The ciliary body epithelial and neuroepithelial tumors (adenoma, adenocarcinoma, and medulloepithelioma) showed uniform strong nuclear PAX8 immunoreactivity. All melanocytic tumors (iris melanoma, ciliary-choroidal melanoma, and melanocytoma) and retinal pigment epithelial neoplasms showed negative results for PAX8. A subset of tumor-associated lymphocytes, most prominent in uveal melanoma, showed positive results for PAX8. The uniformity of the PAX8 staining was superior to the variable cytokeratin staining in the ciliary epithelial neoplasms and the variable Lin28A staining in malignant medulloepithelioma. The veracity of PAX8 staining was equally as robust on cytologic analysis and open-flap biopsy specimens of ciliary epithelial and iris epithelial neoplasms, melanocytoma, and melanoma. CONCLUSIONS: PAX8 has proven to be a very useful diagnostic marker in a select group of adult intraocular tumors, and we highly recommend its inclusion in diagnostic antibody panels of morphologically challenging intraocular neoplasms.

Primary acquired melanosis (PAM) without atypia/WHO low-grade conjunctival melanocytic intraepithelial lesion over areas of oculodermal melanocytosis.

An elderly white man with a history of left oculodermal melanocytosis presented with new onset brown pigmentation of the left bulbar and inferior tarsal conjunctiva. The bulbar conjunctival pigmentation was at the level of the conjunctival epithelium and was overlying areas of typical slate-grey scleral pigmentation characteristic of oculodermal melanocytosis. Both areas of new pigmentation were biopsied. The bulbar conjunctiva revealed primary acquired melanosis (PAM) without atypia with increased melanin production and the tarsal conjunctival biopsy showed PAM without atypia sine pigmentio overlying areas of substantia propria spindle-shaped heavily pigmented melanocytes of oculodermal melanocytosis. The case report examines the relationship between the epithelial and substantia propria melanocytes and correlates the findings with what is known about this association from the dermatopathology literature.

Necrotic choroidal melanoma masquerading as scleritis.

We report a case of a patient who presented with symptoms of acute onset scleritis in the left eye but was found to have an underlying necrotic choroidal melanoma. Asymptomatic choroidal melanoma can undergo spontaneous necrosis and manifest as severe scleritis and should be considered as an important differential.

Conjunctival 'mucoepidermoid carcinoma' revisited: a revision of terminology, based on morphologic, immunohistochemical and molecular findings of 14 cases, and the 2018 WHO Classification of Tumours of the Eye.

In 2018, the consensus meeting for the WHO Classification of Tumours of the Eye decided that conjunctival mucoepidermoid carcinoma should be reclassified as adenosquamous carcinoma, as this represented a better morphological fit. To examine the applicability of this terminology, we studied the clinical, histopathological, immunohistochemical and molecular pathology of 14 cases that were originally diagnosed as conjunctival mucoepidermoid carcinoma. There were 7 (50%) females and 7 (50%) males. The median age was 64 years. The left eye was affected in 8 and the right eye in 6 patients. In-situ carcinoma was present in 11/14 (79%) cases and comprised in-situ squamous cell carcinoma (SCC) and conjunctival intraepithelial neoplasia with mucinous differentiation (CIN-Muc). Invasive carcinoma was present in 11/14 (79%) cases. Group 1 (1/11 cases, 9%) comprised invasive SCC only. Group 2 (6/11 cases, 55%) comprised SCC with mucinous differentiation, manifesting as scattered intracellular mucin, occasionally together with intercellular mucin, with no evidence of true glandular differentiation. Group 3 (3/11 cases. 27%) comprised true adenosquamous carcinoma. Group 4 (1/11 cases, 9%) comprised pure adenocarcinoma. Thirteen of 14 cases (93%) underwent FISH for MAML2 translocation and none were rearranged. Two cases harboured high-risk HPV (type 16 and 18). The combined findings confirm that all lesions in our study were not mucoepidermoid carcinoma, but represented predominantly SCC with mucinous differentiation and adenosquamous carcinoma. We, therefore, recommend future revision of the WHO classification to include SCC with mucinous differentiation alongside adenosquamous carcinoma.