title: Melanoma markers in angiomyolipoma of the liver and kidney: a comparative study.
abstract: BACKGROUND
  Melanoma markers, especially the new microphthalmia transcription factor (mitf), have not been previously compared in hepatic and renal angiomyolipomas.
  
  
  OBJECTIVE
  To evaluate expression of the novel melanocytic markers mitf and tyrosinase in angiomyolipomas, and to compare these markers with the established markers HMB-45 and melan-A in both hepatic and renal tumors.
  
  
  METHODS
  Clinical, histopathologic, and immunohistochemical features of 15 hepatic angiomyolipomas were compared with those of 10 renal angiomyolipomas.
  
  
  RESULTS
  No significant differences between patients with hepatic angiomyolipomas and renal angiomyolipomas were found with respect to age, gender, race, and tumor size. Hepatic angiomyolipomas exhibited a predominance of the epithelioid smooth muscle cell component, in contrast to their renal counterparts, which were predominantly spindled. The smooth muscle cells expressed HMB-45 in 100% of cases in both groups, melan-A in 14 of 15 hepatic angiomyolipomas and 8 of 9 renal angiomyolipomas, mitf in 5 of 12 hepatic angiomyolipomas versus 6 of 10 renal angiomyolipomas, and tyrosinase in 3 of 12 and 2 of 10 hepatic angiomyolipomas and renal angiomyolipomas, respectively. The extent and intensity of immunostaining with HMB-45 and melan-A were dependent on whether spindled or epithelioid cells predominated; the epithelioid cells showed stronger and more widespread reactivity than the spindled cells.
  
  
  CONCLUSIONS
  We believe that the best immunohistochemical marker for confirming the diagnosis of angiomyolipoma is HMB-45, followed by melan-A. Routine use of mitf and/or tyrosinase is not indicated.
authors.affiliation: Department of Hepatic and Gastrointestinal Pathology, Armed Forces Institute of Pathology, Washington, DC 20306-6000, USA.
authors.forename: Hala R
authors.initials: HR
authors.lastname: Makhlouf
authors.forename: Kamal G
authors.initials: KG
authors.lastname: Ishak
authors.forename: Raj
authors.initials: R
authors.lastname: Shekar
authors.forename: Isabell A
authors.initials: IA
authors.lastname: Sesterhenn
authors.forename: Denise Y
authors.initials: DY
authors.lastname: Young
authors.forename: Julie C
authors.initials: JC
authors.lastname: Fanburg-Smith
mesh_terms: D000328:Adult; D000368:Aged; D018207:Angiomyolipoma / Q000378:metabolism* / Q000473:pathology; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000378:metabolism* / Q000473:pathology; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D058965:MART-1 Antigen; D008297:Male; D058950:Melanoma-Specific Antigens; D051739:Microphthalmia-Associated Transcription Factor; D008875:Middle Aged; D014442:Monophenol Monooxygenase / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D058965:MART-1 Antigen; C497234:MITF protein, human; C548667:MLANA protein, human; D058950:Melanoma-Specific Antigens; D051739:Microphthalmia-Associated Transcription Factor; D009363:Neoplasm Proteins; D014157:Transcription Factors; D014442:Monophenol Monooxygenase