title: Cutaneous epithelioid malignant peripheral nerve sheath tumour: a clinicopathological analysis of 11 cases.
abstract: OBJECTIVE
  Epithelioid malignant peripheral nerve sheath tumour (E-MPNST) is a distinctive variant of malignant peripheral nerve sheath tumour characterized by the predominance of epithelioid cells, diffuse S100 positivity and infrequent association with neurofibromatosis type 1. The aim of this study was to further delineate clinicopathological features of cutaneous E-MPNST, correlate them with disease outcome and discuss differential diagnosis.
  
  
  RESULTS
  We analysed 11 cutaneous E-MPNSTs (six males, five females, median age 49 years, median size 1.6 cm). Tumours showed a predilection for lower extremities (45%) and trunk (45%), followed by upper extremity (9%). Follow-up was available for nine of 11 patients (range 24-100 months, median 52 months). Four patients had an uneventful clinical course (44%), two developed local recurrence(s) (22%) and three died due to disseminated disease (33%). No histological parameters were found to predict local recurrence(s), development of distant metastases or disease outcome, including size, percentage of epithelioid component, number of mitoses per 10 high-power fields, degree of nuclear atypia or site of occurrence (dermis, dermis/subcutis, subcutis) (P > 0.05). Immunohistochemically, all tumours were diffusely S100-positive, with a subset displaying loss of integrase interactor 1 (INI1) expression (50%).
  
  
  CONCLUSIONS
  Cutaneous E-MPNST has the potential to pursue an aggressive clinical course, associated with wide dissemination and unfavourable disease outcome.
authors.affiliation: Institute of Pathology, Medical Faculty University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Boštjan
authors.initials: B
authors.lastname: Luzar
authors.affiliation: Division of Dermatology, East Carolina University, Greenville, NC, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Shanesmith
authors.affiliation: Imperial College Hospitals NHS Trust, London, UK.
authors.forename: Rathi
authors.initials: R
authors.lastname: Ramakrishnan
authors.affiliation: Department of Histopathology and Sarcoma Unit, The Royal Marsden NHS Foundation Trust, London, UK.
authors.forename: Cyril
authors.initials: C
authors.lastname: Fisher
authors.affiliation: Department of Dermatopathology, St John's Institute of Dermatology, St Thomas' Hospital, London, UK.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Calonje
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002648:Child; D003937:Diagnosis, Differential; D015622:Epithelioid Cells / Q000378:metabolism / Q000473:pathology; D017809:Fatal Outcome; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D009442:Neurilemmoma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D009456:Neurofibromatosis 1 / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor
keywords: INI1 loss; S100 positivity; clinicopathological analysis; cutaneous; immunohistochemistry; malignant epithelioid peripheral nerve sheath tumour; malignant epithelioid schwannoma; superficial; survival