Angiomyolipoma of the liver in fine-needle aspiration biopsies - Its distinction from hepatocellular carcinoma

BACKGROUND. Angiomyolipoma (AML) of the liver is an uncommon benign lesion that may be difficult to distinguish clinically, radiographically, and morp hologically from hepatocellular carcinoma (HCC). METHODS. Fine-needle aspiration biopsies (FNAB) of three AMLs of the liver were compared with FNABs from eight cases of HCC. Immunoperoxidase stains f or HMB-45, muscle specific actin, and CAM 5.2 were performed on two cell bl ocks and one resection of AML. RESULTS. All three AMLs yielded cellular aspirates. They were composed of c lusters of cells with arborizing transgressing endothelium but no periphera lly wrapping endothelium. Smooth muscle cells of AML showed fibrillar cytop lasm and indistinct cytoplasmic borders; HCC showed granular cytoplasm and distinct cytoplasmic borders. Extramedullary hematopoiesis was present only in AML. Mitotic figures were seen only in HCC. Intranuclear inclusions, nu cleoli, and large, atypical cells were present in both AML and HCC. Fat was seen in only one case of AML and was scant. Immunoperoxidase stains for HM B-45 and smooth muscle actin were positive in AML and negative in adjacent normal liver. CAM 5.2 stain was negative in AML. CONCLUSIONS. The cytologic features seen on FNABs of AML are distinct from those of HCC. Immunoperoxidase stains can aid in the definitive diagnosis o n FNAB. It is important to recognize AML on FNAB to allow conservative clin ical management. Cancer (Cancer Cytopathol) 1999;87:25-30. (C) 1999 America n Cancer Society.