title: Primary PEComa of the bladder treated with primary excision and adjuvant interferon-alpha immunotherapy: a case report.
abstract: BACKGROUND
  Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms of uncertain malignant potential, which have in common the co-expression of muscle and melanocytic immunohistochemical markers.
  
  
  METHODS
  A 48-year-old man presented with dysuria, passage of urinary sediment and lower abdominal discomfort. A three centimeter mass was identified by cystoscopy in the posterior midline of the bladder. Computerized tomography suggested an enterovesical fistula. The patient underwent laparotomy, partial cystectomy and partial small bowel resection. Pathological examination revealed PEComa of the bladder. The patient underwent adjuvant interferon-alpha immunotherapy. Subsequent follow-up procedures, including cystoscopy and imaging, have not revealed evidence of recurrence. The patient is clinically free of disease 48 months after surgery.
  
  
  CONCLUSIONS
  This case represents the second documented PEComa of bladder and demonstrates that adjuvant therapies, including anti-angiogenic and immunotherapy, may be considered for patients with locally advanced or metastatic genitourinary PEComa.
authors.affiliation: Department of Pathology, London Health Sciences Centre and University of Western Ontario, London, Canada. jrparfit@uwo.ca
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Parfitt
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Bella
authors.forename: Bret M
authors.initials: BM
authors.lastname: Wehrli
authors.forename: Jonathan I
authors.initials: JI
authors.lastname: Izawa
mesh_terms: D017024:Chemotherapy, Adjuvant; D015622:Epithelioid Cells / Q000473:pathology*; D006801:Humans; D016898:Interferon-alpha / Q000627:therapeutic use; D007414:Intestinal Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery
chemical_list: D016898:Interferon-alpha