Eyelid sebaceous gland carcinoma: a protocol for a systematic review and meta-analysis of clinicopathological studies of prevalence.

INTRODUCTION: Sebaceous gland carcinoma (SGC) of the eyelid is an aggressive tumour with the ability to metastasise and an increased morbidity. Controversies regarding the epidemiology of this malignant eyelid tumour is widespread in the scientific literature. Western reports repeatedly describes eyelid SGC as a rare occurring tumour in general, accounting for 1%-3% of all eyelid tumours, however studies from Asia have uncovered a higher frequency of eyelid SGC including 54% of all eyelid tumours in Japan, and 43%-56% in India. We wish to retrieve observational data of eyelid SGC prevalence in proportion to total eyelid tumours, from pathological studies published worldwide to resolve this controversy. METHODS AND ANALYSIS: We will search Ovid Medline, EMBASE, Cochrane Central Register of Controlled Trials, Scopus and Google Scholar to identify published reports on eyelid SGC prevalence proportions, aiming to clarify the incidence of the tumour. We will include observational clinicopathological studies reporting prevalence with confirmed histopathology. No limitations on publication date or language will be applied. Data from the individual studies and study quality will be extracted by two individual reviewers. Study quality will be assessed using the JBI Critical Appraisal Instrument for Studies Reporting Prevalence Data. Raw proportions will be transformed and pooled using a random effects model for meta-analysis. And subgroup analysis according to geography will be performed. If data are deemed unsuitable for a meta-analysis, a narrative synthesis will be presented. We will judge the certainty of evidence and present whether this has an overall effect on the results. The results may shed light on a long-standing academic disparity of the scientific literature. ETHICS AND DISSEMINATION: This systematic review does not require ethical approval. The results of this proposed review will be the subject to a publication in an international peer-reviewed journal within the ophthalmic or pathological specialty. PROSPERO REGISTRATION NUMBER: CRD42023487141.

Sebaceous carcinoma in Western Australia: A registry-based study of site-related outcomes.

Sebaceous carcinoma is a rare cutaneous malignancy which is typically regarded as relatively aggressive and has traditionally been subdivided into periorbital or extraorbital tumours. We conducted a retrospective review of all cases of sebaceous carcinoma reported to the Western Australian Cancer Registry between 1987 and May 2019. The incidence of sebaceous carcinoma in Western Australia has increased over the last three decades, with extraorbital tumours being much more common than periorbital tumours. Very few sebaceous carcinomas have led directly to the death of patients; however, adverse outcomes were more likely with periorbital tumours, in particular local recurrence and the need for major surgical intervention.

Comparison of clinicopathologic features, survival, and demographics in sebaceous carcinoma patients with and without Muir-Torre syndrome.

BACKGROUND: Visceral malignancies in patients with Lynch syndrome behave less aggressively than in those without Lynch syndrome. The behavior of sebaceous carcinoma (SC) in Muir-Torre syndrome (MTS), a variant of Lynch syndrome, is incompletely investigated. OBJECTIVE: To investigate features and survival of SC patients with and without MTS. METHODS: Retrospective cohort study in the Surveillance, Epidemiology, and End Results 17 database from 2000 to 2019 of patients with SC. Patients were classified as MTS or non-MTS cases based on a threshold score of 2 on the Mayo MTS risk score. RESULTS: We identified 105 (2.8%) MTS cases and 3677 (97.2%) non-MTS cases. On univariate analysis, MTS patients were younger, had a higher proportion of tumors outside the head/neck, and had fewer high-grade tumors. On Kaplan-Meier analysis, MTS patients trended toward having better SC-specific survival. On multivariate Cox proportional hazards analysis adjusting for other covariates, MTS status was an independent predictor of worse overall survival. However, there was no association between MTS status and SC-specific survival. LIMITATIONS: Given relatively high disease-specific survival in SC, our study may have been underpowered to detect a difference on Kaplan-Meier analysis. CONCLUSIONS: Our study suggests SC does not behave more aggressively in patients with MTS.

Epidemiological characteristics of malignant eyelid tumors at a referral hospital in Japan.

PURPOSE: To clarify the incidence and demographic characteristics of malignant eyelid tumors diagnosed in a single institute in Japan. STUDY DESIGN: Retrospective, observational case series METHODS: Patients with malignant eyelid tumors diagnosed histopathologically at Tokyo Medical University Hospital between 1995 and 2019 were reviewed retrospectively. The incidence and demographic profile of malignant eyelid tumors were analyzed. The number of benign eyelid tumors diagnosed histopathologically during the same period was also counted. RESULTS: A total of 412 patients with histopathologically proven malignant eyelid tumors were included. The most common malignant eyelid tumor was sebaceous carcinoma (n = 180, 44%), followed by basal cell carcinoma (n = 148, 36%), squamous cell carcinoma (n = 35, 9%), lymphoma (n = 28, 7%), Merkel cell carcinoma (n = 11, 3%) and others (n = 10, 2%). Mean age of all patients with malignant eyelid tumor at the time of diagnosis was 71.0 ± 13.0 years. For sebaceous carcinoma, the proportion of female patients was significantly higher than that of male patients (P = 0.0283) and the proportion of involvement of upper eyelid was significantly higher than that of lower eyelid (P = 0.0001). On the other hand, there was no sex predominance in basal cell carcinoma and squamous cell carcinoma. The proportion of involvement of lower eyelid was significantly higher than of upper eyelid in basal cell carcinoma (P = 0.001) and squamous cell carcinoma (P = 0.0012). There were 1433 patients with benign eyelid tumors accounting for 78% of all eyelid tumors during the study period. CONCLUSIONS: Sebaceous carcinoma is the major malignant eyelid tumor in Japan and is more frequent in women than in men. Epidemiology of malignant eyelid tumors may be affected by the trend of population age structure associated with the recent population aging.

Second Primary Neoplasms in Patients With Sebaceous Carcinoma of the Eyelid: A Population-based Study, 2000 to 2016.

PURPOSE: To investigate the risk of second primary neoplasms (SPNs) after primary sebaceous carcinoma of the eyelid (SCE). METHODS: Data on patients diagnosed with primary SCE as their first malignancy were extracted from the Surveillance, Epidemiology, and End Results database from 2000 to 2016. Observed-to-expected ratios of SPNs were calculated to estimate standardized incidence ratios (SIRs). Patients were compared with a reference population (RP) matched for age, gender, and race. RESULTS: Five hundred fifty-nine patients with primary SCE were identified, 16% of whom developed SPNs. SCE patients displayed a 61% increased risk of developing SPNs compared with the RP (p < 0.001). Overall, the risk of SPNs of the lungs (SIR = 1.82; p < 0.05), pancreas (SIR = 2.94; p < 0.05), salivary glands (SIR = 41.65; p < 0.001), and skin (SIR = 8.33; p < 0.05) was elevated. Only non-Hispanic Whites were at an increased risk (SIR = 1.51; p < 0.05). Patients 40-54 years old at the time of diagnosis were at the highest risk of developing SPNs compared with the RP (SIR = 3.15; p < 0.05). Women with SCE experienced an increased risk of breast cancer (SIR = 3.6; p < 0.05) and chronic lymphocytic leukemia (SIR = 8.8; p < 0.01). CONCLUSION: SCE patients are more likely to develop SPNs of the lungs, pancreas, salivary gland, and skin than the RP. Forty to fifty-four years old Caucasian patients are at the highest risk. Women are at an increased risk of developing breast malignancies and chronic lymphocytic leukemia. Clinicians should be cognizant of these risks when managing SCE patients.

Sebaceous carcinoma of the eyelid: 21-year experience in a Nordic country.

PURPOSE: To evaluate the clinical features, diagnostic challenges, management, and prognosis of sebaceous carcinoma (SC) of the eyelids and periocular region in a Nordic country. METHODS: Patients were identified from the Finnish Cancer Registry and the Helsinki University Hospital databases during the 21-year period 1998-2018. Age, sex, location, clinical and histopathologic diagnosis, treatment and outcome were registered. RESULTS: Sebaceous carcinoma (SC) was diagnosed in 32 patients. The incidence was 0.6 per million. Median age at the time of histopathologic diagnosis was 74 years, and 72% of patients were women. Diagnostic delay was often long, median 12 months. The most common cause for delay was misdiagnosis (72%): a chalazion in 34% and a benign tumour in 22%. The most common location was the upper eyelid (53%) and tumour type a solitary nodule (94%). The SC was not correctly diagnosed in 12 (40%) of 30 preoperative biopsies. The treatment for 31 (97%) patients was complete surgical removal with reconstruction. Conjunctival intraepithelial growth was found in 50%. The leading postoperative problem was ocular irritation (30%). During a median follow-up of 58 months, two patients (6%) experienced a local recurrence and one patient died from metastatic SC. CONCLUSIONS: The estimated incidence of SC in Finland was somewhat higher than in other Western countries. The diagnosis was often markedly delayed. Especially differentiation from chalazion continues to be essential. To improve outcomes, it is essential to inform the pathologist about the possibility of SC in eyelid biopsies and specimens and ideally submit them to an ophthalmic pathology service.

Sebaceous Gland Carcinoma: Influence of Age at Presentation on Outcomes.

PURPOSE: To assess the relationship between age at presentation and outcomes of patients with periocular sebaceous gland carcinoma. METHODS: Retrospective case series of 241 patients. RESULTS: Of 241 cases, 29 (12%) were young adults (≤40 years), 122 (51%) were middle-aged adults (41-60 years), and 90 (37%) were older adults (>60 years). Based on the eighth edition of American Joint Committee on Cancer, most tumors belonged to T1 category (n = 78, 32%) on presentation. Wide excisional biopsy was the most common treatment modality (n = 183, 79%). There were no statistically significant differences in the clinical presentation, treatment approaches, and histopathology features amongst different age groups, except pagetoid spread which was higher in middle-aged adults (61%, p = 0.004). The incidence of tumor recurrence was higher in older age group compared to younger age groups, with 5-year, 10-year Kaplan-Meier estimate at 31%, 31% in young adults, 38%, 38% in middle-aged adults, and 45%, 100% in older adults (p = 0.03), respectively. The 10-year Kaplan-Meier estimate rate of locoregional lymph node metastasis, systemic metastasis, and death was higher in young adults (51%, 48%, and 48%, respectively) compared to middle-aged (30%, 17%, and 12%, respectively) and older adults (24%, 25%, and 27%, respectively), but the differences were not statistically significant. CONCLUSIONS: There is no difference in the clinical presentation of periocular sebaceous gland carcinoma based on age. However, the tumor recurrence rate is much higher in the older age group and death higher in younger patients despite the same treatment strategies in all age groups.

Management of recurrent sebaceous gland carcinoma.

OBJECTIVE: To evaluate the incidence and management of recurrent periocular sebaceous gland carcinoma at a tertiary ocular oncology service in the United Kingdom. METHODS: This was a retrospective cohort study of 62 patients with sebaceous gland carcinoma treated between 2004 and 2017. A total of 10 eyes were treated for local recurrence. The following variables were recorded: age and sex of patient; tumour location, histological subtype; recurrence type; treatment and outcome. RESULTS: Of the 62 cases with eyelid SGC, 10 (16%) had recurrences during the study period and satisfied inclusion criteria. There were six (60%) females and four males in the recurrent group. The mean time interval between initial excision and tumour recurrence was 37 months (median 23 months; range 4 to 84 months). Four patients received cryotherapy to the lids and conjunctiva to control recurrent disease and two patients were treated with topical or intralesional chemotherapy. Four patients (40%) underwent orbital exenteration during the study period. Metastasis occurred in 20% over a mean follow-up of 113 months (median 106; range 47-184 months). CONCLUSIONS: The risk factors for local recurrence of SGC after wide excision with paraffin section control were reported, and an approach to these recurrent lesions was proposed. The results of this study will help guide surgeons dealing with the medical and surgical conundrum of recurrent disease. The risk of recurrence is highest in the first 2 years after initial excision.

Ocular and Periocular Tumors in India: An EyeSmart Electronic Medical Record Analysis of 9633 Cases from a Referral Center.

PURPOSE: To describe the epidemiology of ocular and periocular tumors in patients presenting to a multi-tier ophthalmology hospital network in India using the electronic medical records (EMRs) system. METHODS: A retrospective, observational, referral, hospital-based study of 1,142,098 patients. The data were collected using the in-house developed EyeSmart EMR system. RESULTS: During a 6-year study period, 9633 (0.8%) new patients were diagnosed with eye tumors. Of the 9633 patients, 5209 (54%) were male and 4424 (46%) were female. Of all tumors, 6372 (65%) were benign, 282 (3%) were pre-malignant, and 3089 (32%) were malignant in nature, respectively. Overall, the three most common tumors included retinoblastoma (n = 1167, 12%), ocular surface squamous neoplasia (n = 957, 10%), and conjunctival nevus (n = 903, 9%). The three most common benign tumors included conjunctival nevus (n = 903, 9%), eyelid nevus (n = 358, 4%), and orbital dermoid cyst (n = 344, 4%). The three most common malignant tumors included retinoblastoma (n = 1167, 12%), ocular surface squamous neoplasia (n = 957, 10%), and sebaceous gland carcinoma (n = 202, 2%). The most common tumor in 0-10 years' age group was retinoblastoma (n = 1163, 42%), 11-30 years was conjunctival nevus (n = 408, 16%), and > 30 years was ocular surface squamous neoplasia (n = 801, 17%), respectively. CONCLUSIONS: The present study results indicate the incidence and distribution of ocular and periocular tumors in a large cohort in India. Retinoblastoma is the most common tumor encountered in a referral-based comprehensive ophthalmic oncology practice in India. The use of EMRs enables to capture the structured information and big data analysis of the same.

Cutaneous sebaceous tumours and Lynch syndrome: long-term follow-up of 60 patients.

BACKGROUND: Sebaceous neoplasms (SN) may appear sporadically in the general population but may also be part of the Muir-Torre variant of Lynch syndrome (MT-LS). There are few studies in southern Europe on the incidence of MT-LS in the population of patients with SN. AIM: To retrospectively review patients with SN and to analyse their clinical features and the incidence of MT-LS. METHODS: Patients with SN diagnosed between 1995 and 2015 were enrolled in the study. The diagnosis of MT-LS was made according to established clinical criteria and, whenever possible, was confirmed by germline mutation analysis. RESULTS: In 60 patients (32 men, 28 women, mean age 69.22 years), 96 SN were diagnosed: 65 adenomas (67.7%), 16 sebaceomas (16.7%) and 15 carcinomas (15.6%). Of the 60 patients, 50 (83.3%) had a single SN and 10 (16.7%) had multiple lesions. Patients diagnosed with MT-LS (12 patients, 20%) were younger (63.25 years vs. 70.71 years), and had a higher incidence of extrafacial SN (4/12 patients, 33.3%), and were significantly (P < 0.001) more likely to have multiple SNs (8/12, 75%) and keratoacanthomas (KAs) (6/12, 50%). CONCLUSION: Our study confirms that all patients with SN should be investigated, as 20% of our patients were diagnosed with MT-LS. The most specific features of SN associated with MT-LS in our study were the presence of multiple lesions and association with KAs.

Current review of sebaceous cell carcinoma.

PURPOSE OF REVIEW: Periocular sebaceous cell carcinoma is a rare malignancy that is often misdiagnosed leading to increased morbidity and mortality. This review aims to describe current knowledge on the disease to aid clinicians in timely diagnosis and treatment. RECENT FINDINGS: New research has shown that the diagnosis of sebaceous cell carcinoma can be aided with immunohistochemical stains. A revision in the American Joint Committee on Cancer staging system incorporates new tumor size classifications in the staging of eyelid carcinomas. Wide local excision and Mohs micrographic surgery continue to represent the standard of care for initial treatment of localized disease. SUMMARY: The current review highlights diagnostic and treatment modalities to allow clinicians to make timely diagnosis and tailor treatment plans for individual patient presentations.

Incidence and Clinical Features of Rare Cutaneous Malignancies in Olmsted County, Minnesota, 2000 to 2010.

BACKGROUND: The incidence of rare cutaneous malignancies is unknown. Current estimates of rare cutaneous malignancy incidences are based on broad epidemiologic data or single institution experiences, not population-based data. OBJECTIVE: To determine the incidence of several rare nonmelanoma skin cancers. MATERIALS AND METHODS: The authors conducted a retrospective chart review of a population-based cohort between the years 2000 and 2010. Residents of Olmsted County, Minnesota, who were diagnosed with a biopsy-proven nonmelanoma skin cancer-excluding basal cell carcinoma and squamous cell carcinoma-were included in this study. The primary outcome was tumor incidence. Additionally, the authors extracted patient demographics, tumor characteristics, treatment modalities, and outcomes. RESULTS: The age-adjusted and sex-adjusted incidences per 100,000 persons of multiple rare cutaneous malignancies were: atypical fibroxanthoma (1.8), sebaceous carcinoma (0.8), dermatofibrosarcoma protuberans (0.4), microcystic adnexal carcinoma (0.7), eccrine carcinoma (0.4), eccrine porocarcinoma (0.2), and leiomyosarcoma (0.2). CONCLUSION: The authors report population-based incidences and clinical characteristics for these rare cutaneous malignancies. The immune status and smoking status of patients and the treatment and outcomes of these tumors are reported. Additional studies in a broader population are needed to further define the epidemiology and outcomes of these malignancies.

Increased incidence of malignant melanoma and other rare cutaneous cancers in the setting of chronic lymphocytic leukemia.

BACKGROUND: Patients with chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL), or non-Hodgkin lymphoma (NHL) are at increased risk for the development of skin malignancies. OBJECTIVES: This study was conducted to estimate the incidences of rare skin malignancies in patients with CLL/SLL or NHL. METHODS: Patients with a diagnosis of CLL/SLL or NHL recorded in the Surveillance, Epidemiology and End Results (SEER) database during 1992-2007 were identified. Diagnoses of specific skin malignancies were identified from SEER files. RESULTS: During 1992-2007, a total of 128,674 patients with first diagnoses of CLL/SLL or NHL were recorded in SEER; 4743 were excluded because follow-up data were unavailable. Among the remaining 123,931 patients, 28,964 had CLL/SLL and 94,967 had NHL. Standardized incidence ratios (SIRs) for invasive malignant melanoma, Merkel cell carcinoma, malignant fibrous histiocytoma, dermatofibrosarcoma protuberans, Kaposi's sarcoma, and sebaceous carcinoma were 2.3, 8.2, 3.6, 2.5, 2.9, and 1.4, respectively, in CLL/SLL patients and 1.6, 3.2, 1.5, 1.3, 17.6, and 0.8, respectively, in NHL patients. When invasive melanoma was stratified by patient age and sex, the highest SIR (17.8) was found in men aged 0-49 years with CLL (P < 0.001). CONCLUSIONS: Patients with CLL/SLL or NHL have a higher risk for the subsequent development of rare skin cancers. Given the more aggressive nature of these malignancies in this setting, regular monitoring for the development and prompt treatment of cutaneous malignancy is prudent in patients with NHL and particularly in patients with CLL. Regular use of sun protection may decrease the morbidity associated with skin cancer in this immunosuppressed population.

Sebaceous adenomas of the eyelid and Muir-Torre Syndrome.

BACKGROUND/AIMS: Sebaceous adenomas (SAs) are rare, benign sebaceous gland tumours of the eyelid. SAs may be associated with primary internal malignancies. This association is known as Muir-Torre Syndrome (MTS). The purpose of this study was to approximate the prevalence of SAs, to determine the reliability of the clinical diagnosis of SAs and to demonstrate immunohistochemical staining of DNA mismatch repair proteins mutL homologue 1 (MLH1) and mutS homologue 2 (MSH2) for a case of MTS. METHODS: We reviewed the histopathology reports from all eyelid specimens collected between 1993 and 2013 at the Henry C Witelson Ocular Pathology Laboratory to determine the proportion of SAs. For the SAs identified on histopathology, we looked at patient charts to see what diagnosis was originally suspected on clinical examination. Immunohistochemical staining for MLH1 and MSH2 was performed on all SAs to screen for MTS. RESULTS: Of the 5884 eyelid specimens collected, 9 were SAs (6 women, 3 men; 42-72 years old). The diagnosis of SA was suspected clinically in only one of the nine cases based on the gross appearance of the eyelid lesion. Immunohistochemistry revealed one SA case with positive MLH1 expression and negative MSH2 expression. These findings prompted systemic work-up and this patient was diagnosed with MTS after discovery of a colon adenocarcinoma T2M0N0. CONCLUSIONS: The diagnosis of eyelid SA is rare. The importance of this benign eyelid tumour stems from its association with internal malignancies in MTS. Immunohistochemical staining of mismatch repair proteins MLH1 and MSH2 is a valid and accessible strategy for investigating MTS in patients with SAs.

Sebaceous carcinoma in Japanese patients: clinical presentation, staging and outcomes.

AIM: To describe the clinical features, management and correlation of the American Joint Committee on Cancer tumour node metastasis (TNM) staging for eyelid carcinoma with outcomes in Japanese patients with sebaceous carcinoma. METHODS: Multicentre retrospective review of 63 Japanese patients. Tumours were staged using the American Joint Committee on Cancer 7th edition TNM criteria. RESULTS: A distinct mass was the initial presentation in 94% and correct initial diagnosis made in 57% patients. Most tumours (60%) presented at stage T2aN0M0. The remaining TNM stages were: T2bN0M0 (25%); T3aN0M0 (9%); T3bN0M0 (2%); T2bN1M0 (2%); T3bN1M1 (2%). Frozen section controlled excision was performed in 81%. One patient required an orbital exenteration. Median follow-up was 4.2 years. Local recurrence occurred in four patients treated with frozen section controlled excision. Five patients had regional nodal metastases, two of which had T2aN0M0 lesions. T3a tumours and greater were significantly associated with local recurrence but not regional nodal metastasis. One patient died due to disease. One patient is alive with disease, and remaining patients were alive without disease at last follow-up. CONCLUSIONS: In this Japanese cohort, an eyelid mass was the main clinical presentation of sebaceous carcinoma. Contrary to previous reports, T2a tumours smaller than 10 mm were associated with regional nodal metastases.

Eyelid tumours and pseudotumours in Hong Kong: a ten-year experience.

OBJECTIVE: To describe the clinicopathological characteristics of patients with eyelid tumours in Hong Kong. DESIGN: Retrospective case series. SETTING: A tertiary eye centre in Hong Kong. PATIENTS: A computerised retrieval system was used to identify all patients who underwent eyelid mass excisions with histological reports, encountered in the period 2000 to 2009, in a tertiary eye centre. The demographics (age, gender), clinical features (laterality, tumour topography), and the pathological diagnosis of each patient were documented. Descriptive statistical tabulation and analyses were performed on the data. RESULTS: In all, 198 patients were identified; all were Chinese. Their mean age was 54 years for benign lesions and 68 years for malignant ones. Women were more commonly affected. Benign tumourous lesions occurred more commonly on the upper (n=91; 54%) than lower eyelid (n=79; 47%), whereas malignant lesions more often affected the lower (n=17, 61%) than upper (n=11, 39%) eyelid. The distribution of left and right eye involvement was similar (103 vs 101, respectively). In six patients, there were bilateral benign lesion. Regarding benign masses, 45 (27%) were intradermal neavi, 38 (22%) were squamous papillomas, 25 (15%) were seborrhoeic keratosis lesions, 14 (8%) were epidermoid cysts, and 7 (4%) were compound naevi. Regarding malignant eyelid tumours, the most common was basal cell carcinomas (n=12, 43%), 5 (18%) were squamous cell carcinomas, 3 (11%) were actinic keratosis lesions, and 2 (7%) each were sebaceous gland carcinomas and melanomas. CONCLUSION: Benign lesions constituted the majority of these eyelid tumours. Among the malignant lesions, basal cell carcinoma was the commonest type, with lower lid involvement in majority. Sebaceous gland carcinoma is not rare, which is in contrast to Caucasian populations. The relative frequencies of the most common malignant tumours in Hong Kong differed substantially from those reported in other Asian studies.

Observational prospective cohort study of patients with newly-diagnosed ocular sebaceous carcinoma.

PURPOSE: To investigate the epidemiology and clinicopathological management for ocular sebaceous carcinoma (OSC) in the UK. METHODS: Observational prospective cohort study of patients with newly-diagnosed OSC. The British Ophthalmological Surveillance Unit captured incident cases of OSC between 2008 and 2010. Incident and 6-month follow-up questionnaires from reporting ophthalmologists captured OSC demographic and clinical data. RESULTS: Data were available on 51 patients with unilateral OSC (response rate 85%). The UK estimated annual incidence was 0.41 cases per million population (95% CI 0.31 to 0.54). Median age was 70 years (SD 14, range 28-98) with 57% women. OSC location was upper lid (54%), lower lid (20%), multicentric (14%) and caruncle (12%). Most common misdiagnoses included chalazion (42%), basal cell carcinoma (30%) and blepharoconjunctivitis (16%), with median delay in diagnosis of 10 months (SD 9, range 0.5-36). Specialist ophthalmic pathologists performed diagnostics in 62%, with pagetoid/intraepithelial spread present in 39%. Misdiagnosis of chalazion (p=0.019) and pagetoid tumour spread (p=0.016) was associated with a significant diagnostic delay (one-way ANOVA/R(2)). Primary surgical management involved excision with reconstruction (49%), primary exenteration (10%) and Mohs surgery (8%). There were three deaths (out of 51) during the study period; one patient died of OSC-related disease and the other two due to other causes. CONCLUSIONS: This population-based prospective study confirms OSC as a rare cancer in the UK. Masquerade syndromes result in significant diagnostic delays and increase the risk of pagetoid tumour spread. There is considerable UK variation in pathological and surgical management, and ocular reconstruction and radical surgery is often required for OSC due to delayed presentation.