title: Pleomorphic spindle cell dermal neoplasm with dot-like keratin reactivity: keratin-positive AFX or carcinoma?
abstract: Atypical fibroxanthoma (AFX) is an uncommon cutaneous neoplasm of pleomorphic myofibroblast-like cells. Diagnosis requires exclusion of other undifferentiated spindle and pleomorphic cell neoplasms by immunohistochemistry. We report two patients with p63-non-reactive spindle cell neoplasms which resembled AFX but demonstrated anomalous dot-like immunolabeling with antibodies to high molecular weight keratin and keratin 5. One case recurred locally, suggesting such lesions may behave aggressively. Whether these lesions represent keratin-positive dermal sarcomas or poorly differentiated carcinomas is debatable. Regardless of exact classification, our experience suggests such cases should be managed as high-risk non-melanoma skin cancers.
authors.affiliation: Department of Pathology and Laboratory Medicine Division of Dermatology, University of Kansas School of Medicine, Kansas City, KS, USA.
authors.forename: Ransom
authors.initials: R
authors.lastname: Ellis
authors.affiliation: Department of Internal Medicine, Division of Dermatology, University of Kansas School of Medicine, Kansas City, KS, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Chase
authors.affiliation: Department of Internal Medicine, Division of Dermatology, University of Kansas School of Medicine, Kansas City, KS, USA.
authors.forename: Alycia
authors.initials: A
authors.lastname: Barland
authors.affiliation: Department of Internal Medicine, Division of Dermatology, University of Kansas School of Medicine, Kansas City, KS, USA.
authors.forename: Anand
authors.initials: A
authors.lastname: Rajpara
authors.affiliation: Department of Pathology and Laboratory Medicine Division of Dermatology, University of Kansas School of Medicine, Kansas City, KS, USA.
authors.forename: Garth R
authors.initials: GR
authors.lastname: Fraga
mesh_terms: D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D003937:Diagnosis, Differential; D051677:Histiocytoma, Malignant Fibrous / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007633:Keratins / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D015580:Mohs Surgery / Q000379:methods; D009364:Neoplasm Recurrence, Local; D018331:Nevus, Spindle Cell / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology*; D012878:Skin Neoplasms / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology*; D014973:Xanthomatosis / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology*
chemical_list: C081876:CKAP4 protein, human; D008565:Membrane Proteins; D007633:Keratins
keywords: atypical fibroxanthoma; dot-like keratin; immunohistochemistry; squamous cell carcinoma