title: Protein gene product 9.5 (PGP9.5) expression in benign cutaneous mesenchymal, histiocytic, and melanocytic lesions: comparison with cellular neurothekeoma.
abstract: Cellular neurothekeoma (CNTK) frequently enters the differential diagnosis of a benign dermal cellular proliferation. Diagnosis often relies on immunohistochemistry including the use of protein gene product 9.5 (PGP9.5). A previous study demonstrated PGP9.5 expression across a wide variety of soft tissue neoplasms. We explored the utility of this antibody in distinguishing CNTK from other benign dermal-based lesions. A cohort of CNTK (n=7) and benign cutaneous lesions of neural (n=28), fibrohistiocytic (n=23), fibroblastic (n=25), histiocytic (n=18), myofibroblastic (n=7), smooth muscle (n=14), and melanocytic (n=12) differentiations were immunostained with PGP9.5. Staining was graded by H-score and compared with CNTK. A significantly higher H-score was found in CNTK compared with the fibrohistiocytic (p=0.0001), histiocytic (p=0.0016), myofibroblastic (p=0.0003), smooth muscle (p<0.0001), and melanocytic (p=0.0004) groups, with the exceptions of plexiform fibrohistiocytic tumour, xanthoma, and xanthogranuloma. No significant difference was found when comparing CNTK with fibroblastic and neural lesions, with the exceptions of neurofibroma and perineurioma. In conclusion, PGP9.5 is helpful in distinguishing CNTK from most benign cutaneous fibrohistiocytic, histiocytic, myofibroblastic, smooth muscle, and melanocytic lesions. In addition to CNTK and neural lesions, PGP9.5 is also expressed in benign fibroblastic lesions, and therefore distinction of these lesions should not be based on PGP9.5 positivity.
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Grace Y
authors.initials: GY
authors.lastname: Wang
authors.affiliation: Pathology Service, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.
authors.forename: Rosalynn M
authors.initials: RM
authors.lastname: Nazarian
authors.affiliation: Department of Biostatistics, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Lili
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI, United States; Department of Dermatology, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Alexandra C
authors.initials: AC
authors.lastname: Hristov
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI, United States; Department of Dermatology, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Rajiv M
authors.initials: RM
authors.lastname: Patel
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI, United States; Department of Dermatology, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Fullen
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI, United States; Department of Dermatology, University of Michigan, Ann Arbor, MI, United States. Electronic address: mpchan@med.umich.edu.
authors.forename: May P
authors.initials: MP
authors.lastname: Chan
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics; D003937:Diagnosis, Differential; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D018317:Nerve Sheath Neoplasms / Q000175:diagnosis / Q000473:pathology*; D018321:Neurothekeoma / Q000175:diagnosis / Q000473:pathology*; D012878:Skin Neoplasms / Q000175:diagnosis / Q000473:pathology*; D012983:Soft Tissue Neoplasms / Q000175:diagnosis / Q000473:pathology*; D043222:Ubiquitin Thiolesterase / Q000032:analysis* / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; C482860:UCHL1 protein, human; D043222:Ubiquitin Thiolesterase
keywords: Cellular neurothekeoma; PGP9.5; immunohistochemistry