title: Balloon cell nevus of the iris.
abstract: Balloon cell nevus is a rare histopathological lesion characterized by a predominance of large, vesicular and clear cells, called balloon cells. There is only 1 case of balloon cell nevus of the iris reported in the literature.
  
  
  METHODS
  A 55 year-old man presented a pigmented elevated lesion in the right iris since the age of 12 years old. The lesion had been growing for the past 2 years and excision was performed. Histopathological examination showed a balloon cell nevus composed of clear and vacuolated cells without atypia. A typical spindle cell nevus of the iris was also observed. The differential diagnosis included xanthomatous lesions, brown adipocyte or other adipocytic lesions, clear cell hidradenoma, metastatic clear cell carcinoma of the kidney and clear cell sarcoma. The tumor was positive for Melan A, S100 protein and HMB45.
  
  
  CONCLUSIONS
  Balloon cell nevus of the iris is rare but should be considered in the differential diagnosis of melanocytic lesions of the iris.
authors.affiliation: Department of Pathology, Laval University, Canada.
authors.forename: Mohib W
authors.initials: MW
authors.lastname: Morcos
authors.affiliation: Department of Pathology and Molecular Medicine, McMaster University, Canada. Electronic address: alexandreodashiro@gmail.com.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Odashiro
authors.affiliation: Department of Ophthalmology, Laval University, Canada.
authors.forename: Richard
authors.initials: R
authors.lastname: Bazin
authors.affiliation: Henry C. Witelson Ocular Pathology Laboratory, McGill University, Canada.
authors.forename: Patricia Rusa
authors.initials: PR
authors.lastname: Pereira
authors.affiliation: Department of Pathology and Molecular Medicine, McMaster University, Canada.
authors.forename: Aisling
authors.initials: A
authors.lastname: O'Meara
authors.affiliation: Henry C. Witelson Ocular Pathology Laboratory, McGill University, Canada.
authors.forename: Miguel N
authors.initials: MN
authors.lastname: Burnier
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D007498:Iris / Q000473:pathology*; D008297:Male; D008545:Melanoma / Q000175:diagnosis / Q000473:pathology*; D008875:Middle Aged; D009508:Nevus, Pigmented / Q000175:diagnosis / Q000473:pathology*; D009418:S100 Proteins / Q000378:metabolism; D012878:Skin Neoplasms / Q000175:diagnosis / Q000473:pathology*
chemical_list: D009418:S100 Proteins
keywords: Balloon cell nevus; Iris; Melanoma; Pigment; Tumor