title: Benign ocular adnexal tumours of apocrine, eccrine or hair follicle origin.
abstract: BACKGROUND
  The differential diagnosis of malignant eyelid tumours, particularly basal cell carcinoma (BCC), includes tumours of skin appendages. The incidence of these adnexal tumours has not been well established. This study aimed to determine the incidence and review the main clinicopathological features of benign tumours arising from skin appendages of the eyelid with apocrine, eccrine or hair follicle differentiation.
  
  
  METHODS
  The histopathological diagnoses of 7751 ophthalmic specimens retrieved from 6967 patients between September 1993 and March 2002 at the Henry C. Witelson Ophthalmic Pathology Laboratory and Registry, McGill University, Montreal, were retrospectively reviewed. Clinical data and histopathological diagnoses were obtained for 228 benign adnexal tumours of apocrine, eccrine or hair follicle origin. New histopathological slides were made from the paraffin-embedded specimens and stained with hematoxylin-eosin and periodic acid-Schiffs reagent.
  
  
  RESULTS
  Of the 228 benign adnexal tumours, 182 were diagnosed as apocrine or eccrine hydrocystoma (79.8%), 12 pilomatrixoma (5.3%), 12 syringoma (5.3%), 11 trichilemmoma (4.8%), 5 syringocystadenoma papilliferum (2.2%), 3 trichoepithelioma (1.3%) and 3 trichofolliculoma (1.3%). Discrepancies between clinical and histopathological diagnoses were noted in 22 cases (9.6%).
  
  
  CONCLUSIONS
  Benign tumours originating from skin appendages of the eyelid are rare and frequently have apocrine or eccrine differentiation. These tumours, particularly those originating from the hair follicle, should be considered in the differential diagnosis of BCC of the eyelid.
authors.affiliation: Henry C. Witelson Ophthalmic Pathology Laboratory and Registry and the Department of Ophthalmology, McGill University Health Centre, Montreal, Que.
authors.forename: Pinar Cakar
authors.initials: PC
authors.lastname: Ozdal
authors.forename: Sonia A
authors.initials: SA
authors.lastname: Callejo
authors.forename: François
authors.initials: F
authors.lastname: Codère
authors.forename: Miguel N
authors.initials: MN
authors.lastname: Burnier
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001050:Apocrine Glands / Q000473:pathology; D002170:Canada / Q000453:epidemiology; D002280:Basal Cell Carcinoma / Q000473:pathology; D018280:Carcinoma, Skin Appendage / Q000453:epidemiology / Q000473:pathology*; D002454:Cell Differentiation; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D004439:Eccrine Glands / Q000473:pathology; D005142:Eyelid Neoplasms / Q000453:epidemiology / Q000473:pathology*; D018859:Hair Follicle / Q000473:pathology; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D012189:Retrospective Studies