title: Anorectal malignant melanoma. A clinicopathologic study, including immunohistochemistry and DNA flow cytometry.
abstract: BACKGROUND
  Anorectal malignant melanoma is a rare tumor with an extremely poor prognosis. DNA flow cytometric study as well as detailed immunohistochemical study have not been reported previously.
  
  
  METHODS
  Eighteen cases of anorectal melanoma were studied, including immunohistology for melanoma markers and epithelial markers and DNA flow cytometric study of paraffin blocks.
  
  
  RESULTS
  Most patients were Ashkenazi Jews, compared with Sephardi Jews and Arabs. Of the 17 patients followed, 14 died of disease at 4-39 months from presentation. Three patients were alive with disease at 12, 53, and 72 months of follow-up. Tumor thickness ranged from 3-35 mm (mean, 12.8 mm). The 2 long term survivors had tumor thickness < or = 7 mm. No correlation was found between the mode of primary surgical treatment (8 patients: abdominoperineal resection; 10 patients: local excision) and outcome. Vimentin, HMB-45, and S-100 protein stainings were positive in 18, 17, and 15 tumors, respectively. Polyclonal carcinoembryonic antigen (CEA), broad-spectrum cytokeratin, epithelial membrane antigen, monoclonal CEA, and TAG-72 (B72.3) stainings were positive in 13, 3 (only focal and rare staining), 2, 0, and 0 tumors, respectively. Thirteen tumors had adequate material for DNA analysis, and all were DNA aneuploid. S-phase fraction could be assessed in 11 tumors and ranged from 7.7-24% (mean, 14%). An S-phase fraction of < 10% was observed in the 2 long term survivors.
  
  
  CONCLUSIONS
  Anorectal melanoma in this study carried a grave prognosis. The frequent staining for polyclonal CEA (with negative monoclonal CEA staining) was probably due to nonspecific cross-reacting antigens. The occasional staining for epithelial markers warrants a comprehensive immunohistochemical study to ensure a correct diagnosis, especially in small biopsies of amelanotic undifferentiated tumors that lack junctional changes. The aneuploidy of all tested tumors reflected their highly malignant behavior. A trend toward longer survival was observed in patients with thin tumors and an S-phase fraction of < 10%. However, due to the small number of survivors, the latter observation should be further tested in a larger scale series.
authors.affiliation: Department of Pathology, Rambam Medical Center, Haifa, Israel.
authors.forename: O
authors.initials: O
authors.lastname: Ben-Izhak
authors.forename: R
authors.initials: R
authors.lastname: Levy
authors.forename: S
authors.initials: S
authors.lastname: Weill
authors.forename: G
authors.initials: G
authors.lastname: Groisman
authors.forename: H
authors.initials: H
authors.lastname: Cohen
authors.forename: S
authors.initials: S
authors.lastname: Stajerman
authors.forename: I
authors.initials: I
authors.lastname: Misselevich
authors.forename: S
authors.initials: S
authors.lastname: Nitecky
authors.forename: S
authors.initials: S
authors.lastname: Eidelman
authors.forename: H
authors.initials: H
authors.lastname: Kerner
mesh_terms: D000328:Adult; D000368:Aged; D001005:Anus Neoplasms / Q000737:chemistry / Q000235:genetics / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008545:Melanoma / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000737:chemistry / Q000235:genetics / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm