title: Adipophilin expression in sebaceous tumors and other cutaneous lesions with clear cell histology: an immunohistochemical study of 117 cases.
abstract: Adipophilin is a monoclonal antibody against a protein on the surface of intracellular lipid droplets, and it was recently shown to be expressed in sebocytes and sebaceous lesions. This study examines adipophilin expression in various sebaceous lesions and other cutaneous tumors with a clear cell histology that may mimic sebaceous differentiation. A total of 117 cutaneous clear cell lesions including 16 sebaceous adenomas, 25 sebaceous carcinomas, 8 basal cell carcinomas, 12 squamous cell carcinomas, 6 xanthomas, 10 xanthelasmas, 10 xanthogranulomas, 4 balloon cell nevi, 5 trichilemmomas, 8 clear cell hidradenomas, and 13 metastatic renal cell carcinomas were examined using immunohistochemistry for the expression of adipophilin. Of these 117 lesions, 42 (36%) were from the periocular region. Adipophilin was expressed in 16 of 16 (100%) sebaceous adenomas, 23 of 25 (92%) sebaceous carcinomas, 10 of 10 (100%) xanthelasmas, 9 of 10 (90%) xanthogranulomas, 6 of 6 (100%) xanthomas, and 9 of 13 (62.5%) metastatic renal cell carcinomas. The characteristic staining pattern differed between sebaceous and non-sebaceous tumors with the former showing a membranous vesicular pattern and the latter being more granular. Adipophilin expression was not seen in any of the other lesions with clear cell histology, basal cell carcinomas, or squamous cell carcinomas, including cases that had focal clear cell differentiation. Adipophilin can be valuable in an immunohistochemical panel when evaluating cutaneous lesions with clear cell histology as it identifies intracytoplasmic lipid vesicles in sebaceous and xanthomatous lesions. In periocular lesions, it is effective in helping to exclude basal cell carcinoma and squamous cell carcinoma when sebaceous carcinoma is under consideration. Adipophilin expression is not as useful for the differential diagnosis that includes metastatic renal cell carcinoma, a rare but important, diagnostic differential. The pattern of adipophilin reactivity is important to observe as membranous vesicular staining is suggestive of intracellular lipids whereas granular cytoplasmic reactivity is not.
authors.affiliation: Departments of Pathology and Dermatology, Baylor College of Medicine, The University of Texas, M.D. Anderson Cancer Center, Houston, TX, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Ostler
authors.forename: Victor G
authors.initials: VG
authors.lastname: Prieto
authors.forename: Jon A
authors.initials: JA
authors.lastname: Reed
authors.forename: Michael T
authors.initials: MT
authors.lastname: Deavers
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Lazar
authors.forename: Doina
authors.initials: D
authors.lastname: Ivan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D018294:Neoplasms, Adnexal and Skin Appendage / Q000378:metabolism / Q000473:pathology; D010455:Peptides / Q000378:metabolism*; D000070780:Perilipin-2; D012626:Sebaceous Gland Neoplasms / Q000378:metabolism* / Q000473:pathology*; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology*; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D008565:Membrane Proteins; C000602982:PLIN2 protein, human; D010455:Peptides; D000070780:Perilipin-2