Multifocal angiomyolipoma affecting the liver and lung without tuberous sclerosis

The occurrence of angiomyolipoma (AML) in tissue other than the kidney is uncommon, as is multiple AML developing exclusively in organs other than the kidney. This report describes a case in which AML occurred multifocally in the liver and lung, but spared the kidney, and which might have been associated with tuberous sclerosis complex (TSC). A Japanese woman underwent a partial hepatectomy for a suspected malignant liver tumour at the age of 57. The tumour consisted predominantly of a trabecular arrangement of myoid cells with a sinusoidal pattern and inflammatory cell infiltration, and was diagnosed as a primary liver AML by HMB-45 immunoreactivity. Five years later, multiple nodules were found in both lungs, for which video assisted thoracic surgery was performed. The tumour showed a mixture of epithelioid cells containing HMB-45 positive material and mature lipocytes, and was subsequently diagnosed as AML. Molecular analysis of both lesions showed no allelic loss of the TSC1 and TSC2 regions. Molecular analysis of the tumours ruled out an association with TSC, and both liver and lung lesions displayed benign histological features, so that these were probably multifocal lesions of AML without TSC.