title: Primary cutaneous ewing's sarcoma/primitive neuroectodermal tumor: report of the first case diagnosed on aspiration cytology.
abstract: BACKGROUND
  Extraskeletal Ewing's sarcoma (ES) was first recognized as a soft tissue tumor in 1975. Primacy cutaneous occurrence of Ewing's sarcoma/primitive neuroectodermnal tumor (ES/PNET) has been reported in only 31 cases so far. To the best of our knowledge, there is no report of preoperative cytologic diagnosis of cutaneous ES/PNET in the available literature except for this one.
  
  
  METHODS
  A young adult presented with a recurrent swelling on the medial aspect of the left leg that had been present for the past 5 years. Fine needle aspiration cytology yielded cellular smears showing a small round cell tumor. Immunostaining on cell block material showed positivity for CD99, S-100 protein and neuron-specific enolase. A cytologic diagnosis of primary cutaneous ES/PNET was made. Local excision was performed, and the patient was well after 2 years of follow-up.
  
  
  CONCLUSIONS
  Primary cutaneous ES/PNET is a rare cutaneous tumor with a favorable clinical outcome. It can be diagnosed on cytology; however, immunocytochemistry is mandatory for differentiation from other small round cell tumors.
authors.affiliation: Department of Pathology, Hindu Rao Hospital, Malka Ganj, Delhi, India.
authors.forename: Sonali
authors.initials: S
authors.lastname: Kalra
authors.forename: Ruchika
authors.initials: R
authors.lastname: Gupta
authors.forename: Sompal
authors.initials: S
authors.lastname: Singh
authors.forename: Kusum
authors.initials: K
authors.lastname: Gupta
authors.forename: Madhur
authors.initials: M
authors.lastname: Kudesia
mesh_terms: D000071443:12E7 Antigen; D015703:Antigens, CD / Q000378:metabolism; D044963:Biopsy, Fine-Needle; D015815:Cell Adhesion Molecules / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D018242:Neuroectodermal Tumors, Primitive / Q000378:metabolism / Q000473:pathology*; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D009418:S100 Proteins / Q000378:metabolism; D012512:Sarcoma, Ewing / Q000378:metabolism / Q000473:pathology*; D012867:Skin / Q000378:metabolism / Q000473:pathology; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology*; D055815:Young Adult
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D009418:S100 Proteins; D010751:Phosphopyruvate Hydratase