title: Desmoplastic small round cell tumor: a rare cause of a progressive brachial plexopathy.
abstract: BACKGROUND
  Desmoplastic small round cell tumor (DSRCT) is an uncommon, embryonic-type neoplasm, typically presenting as an abdominal mass in young men. A single case of DSRCT arising in the peripheral nervous system has been reported previously.
  
  
  METHODS
  The clinical course, imaging, electrophysiological, intraoperative, histopathological, molecular findings, and postoperative follow-up are reported.
  
  
  RESULTS
  A 43-year-old man presented with slowly progressive right brachial plexopathy. Magnetic resonance imaging revealed an enlarged medial cord with heterogeneous contrast enhancement. Histology showed a "small round cell" neoplasm with a polyphenotypic immunoprofile, including epithelial and mesenchymal markers. A pathognomonic fusion of Ewing sarcoma breakpoint region 1 and Wilms tumor 1 genes (EWSR1/WT1) was present. Treatment involved gross total excision and local radiotherapy.
  
  
  CONCLUSIONS
  Our findings confirm the occurrence of DSRCT as a primary peripheral nerve tumor. Despite its usually very aggressive clinical course, prolonged recurrence-free survival may be reached. Histomorphology and immunoprofile of DSRCT may lead to misdiagnosis as small cell carcinoma.
authors.affiliation: Department of Neurology, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland.
authors.forename: Jan
authors.initials: J
authors.lastname: Mathys
authors.forename: Istvan
authors.initials: I
authors.lastname: Vajtai
authors.forename: Esther
authors.initials: E
authors.lastname: Vögelin
authors.forename: Dieter R
authors.initials: DR
authors.lastname: Zimmermann
authors.forename: Christoph
authors.initials: C
authors.lastname: Ozdoba
authors.forename: Ekkehard
authors.initials: E
authors.lastname: Hewer
mesh_terms: D000328:Adult; D020516:Brachial Plexus Neuropathies / Q000175:diagnosis / Q000209:etiology*; D003131:Combined Modality Therapy; D058405:Desmoplastic Small Round Cell Tumor / Q000150:complications* / Q000175:diagnosis / Q000628:therapy; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010524:Peripheral Nervous System Neoplasms / Q000150:complications* / Q000175:diagnosis / Q000628:therapy; D049268:Positron-Emission Tomography; D016896:Treatment Outcome
keywords: EWSR1/WT1 fusion nerve biopsy; brachial plexopathy; desmoplastic small round cell tumor; positron emission tomography