Case: AP194
Contributor's Comment: The present case shows classical features of a liver cell adenoma and is related to the use of oral contraceptive. Recent studies on liver adenomas reveal that about half of the sporadic adenomas has bi-allelic inactivation of TCF-1 (transcription factor 1) which encodes hepatocyte nuclear factor 1 (HNF-1) (Ref: Nature Genetics. 32:312-315, 2002). This group of mutated adenoma is more steatotic in appearance and less related to the use of OC. These characteristics are common in those in liver adenomatosis (Ref: J Hepatol 39:77-85, 2003). Furthermore, in familial cases of liver adenomatosis, the patients have germline mutations and are associated with maturity onset diabetes of the young. In these adenomatosis cases, the lesions, especially the smaller ones, may be mistaken for focal fatty change both radiologically and pathologically. Immunostaining for CD34 to study the vascular architecture may be necessary for the distinction. (MST)