Common and epithelioid variants of hepatic angiomyolipoma exhibit clonal growth and share a distinctive immunophenotype.
Angiomyolipoma represents a rare liver tumor of uncertain histogenesis that is commonly considered a hamartoma. A series of 12 hepatic angiomyolipomas, including 3 samples of the epithelioid subtype, was analyzed for clonality using the human androgen receptor gene locus (HUMARA). Four of 6 informative cases revealed monoclonality. The polyclonal pattern in the 2 remaining cases was most probably caused by excessive infiltration of inflammatory cells. Monoclonality with an identical X-chromosomal inactivation pattern in all nodules was found in a multifocal recurrent tumor indicating a metastatic process. Despite the morphologic heterogeneity, all tumors displayed an identical immunohistochemical labeling pattern. It is concluded that different subtypes of hepatic angiomyolipoma exhibit a monoclonal and hence probably neoplastic growth and share an identical immunophenotype suitable for their identification even in small biopsy specimens. The epithelioid subtype may give rise to intrahepatic metastasis.
Institut für Pathologie, Medizinische Hochschule Hannover, Hannover, Germany. Flemming.Peer@mh-hannover.de
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Flemming
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Lehmann
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Becker
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Klempnauer
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Kreipe
D000328:Adult; D000368:Aged; D018207:Angiomyolipoma / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D008113:Liver Neoplasms / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011944:Receptors, Androgen / Q000235:genetics; D014960:X Chromosome
D011944:Receptors, Androgen