title: Low-grade endometrial stromal sarcoma arising from sciatic nerve endometriosis.
abstract: BACKGROUND
  Endometrial stromal sarcoma arising from extrauterine endometriosis is a rare and not easily diagnosed tumor. We present a case arising from sciatic nerve endometriosis in a 50-year-old woman.
  
  
  METHODS
  The patient had a long history of endometriosis and presented with a left buttock mass and motor deficit. Magnetic resonance imaging showed a large tumor of the sciatic nerve with pelvic extension. She underwent total hysterectomy, bilateral salpingo-oophorectomy, and excision of pelvic endometriotic pockets, allowing the diagnosis of low-grade endometrial stromal sarcoma arising from endometriosis. She received systemic chemotherapy, gonadotropin-releasing hormone agonist therapy, and palliative radiation therapy, but her disease progressed.
  
  
  CONCLUSIONS
  Aggressive endometriosis raises important diagnostic and therapeutic difficulties and may correspond to misdiagnosed rare malignant neoplasms, which should be treated.
authors.affiliation: Department of Pathology, Institut Claudius Regaud, Toulouse, France. lacroix_m@icr.fnclcc.fr
authors.forename: Magali
authors.initials: M
authors.lastname: Lacroix-Triki
authors.forename: Laurent
authors.initials: L
authors.lastname: Beyris
authors.forename: Pierre
authors.initials: P
authors.lastname: Martel
authors.forename: Bernard
authors.initials: B
authors.lastname: Marques
mesh_terms: D001707:Biopsy, Needle; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D003131:Combined Modality Therapy; D018450:Disease Progression; D016889:Endometrial Neoplasms / Q000473:pathology* / Q000628:therapy; D004715:Endometriosis / Q000473:pathology* / Q000503:physiopathology; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007813:Laparotomy; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009367:Neoplasm Staging; D018714:Radiotherapy, Adjuvant; D018203:Sarcoma, Endometrial Stromal / Q000473:pathology* / Q000628:therapy; D012584:Sciatic Nerve / Q000473:pathology*