title: Clinicopathologic and immunohistochemical studies of conjunctival large cell acanthoma, epidermoid dysplasia, and squamous papilloma.
abstract: OBJECTIVE
  To evaluate clinicopathologically and immunohistochemically a spectrum of conjunctival squamous proliferations.
  
  
  METHODS
  Retrospective clinicopathologic study.
  
  
  METHODS
  One large cell acanthoma, 7 epidermoid dysplasias, and 4 squamous papillomas were evaluated with microscopy and biomarkers Ki-67, p53, epithelial membrane antigen (EMA), Ber-EP4, AE1, AE3, and 8 individual cytokeratins. Normal associated conjunctiva served as a baseline for interpretation.
  
  
  RESULTS
  The large cell acanthoma recurred 4 times but retained its benign histopathologic features. The cells were 2-3 times larger than the keratinocytes of the normal conjunctiva and did not display atypia. Immunohistochemistry revealed a low Ki-67 proliferation index (PI) in the large cell acanthoma compared with high indices in dysplasias and papillomas. p53 was negative in the nuclei of normal epithelium while positive in all neoplasms, most intensely in the dysplasias. Immunostaining showed similar staining patterns for cytokeratins in large cell acanthoma and normal conjunctiva, except for full-thickness CK14 positivity and CK7 negativity in the lesion. Dysplasias generally lost normal CK7 expression and frequently abnormally expressed CK17. The papillomas displayed a normal cytokeratin pattern but exhibited a higher than normal PI and weak p53 positivity.
  
  
  CONCLUSIONS
  Conjunctival large cell acanthoma is a morphologically distinctive clonal entity with clinical and immunohistochemical phenotypic characteristics denoting a dysplasia of minimal severity. Because of recurrences without invasion, it requires treatment. Dysplasias exhibited more deviant biomarker abnormalities including frequent aberrant full-thickness CK17 positivity and CK7 negativity. The absence of major cytokeratin derangements in the squamous papillomas may be of ancillary diagnostic value for lesions displaying borderline cytologic features.
authors.affiliation: David G. Cogan Laboratory of Ophthalmic Pathology, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts. Electronic address: Fred_Jakobiec@meei.harvard.edu.
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Jakobiec
authors.forename: Pia R
authors.initials: PR
authors.lastname: Mendoza
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Colby
mesh_terms: D049309:Acanthoma / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis*; D002278:Carcinoma in Situ / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D003230:Conjunctival Neoplasms / Q000737:chemistry* / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D010212:Papilloma / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D016612:Paraffin Embedding; D012189:Retrospective Studies
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins