Papillary mucinous adenomaarising in adenomyomatous hyperplasia ofthegall bladder

A caseofpapillary mucinousadenoma arising inadenomyomatous hyperplasia (AMH)ofthegall bladder isreported. The lesion wasunsuspected anddiscovered by routine palpation ofthegallbladder during laparotomy. The adenoma developed within fundal AMH andshowedcytological atypia. Thiscaseillustrates thatneoplastic proliferation isindeedpossible inAMH andchallenges theclassical opinion that AMH isdevoid ofneoplastic potential. (7Clin Pathol 1995;48:965-967)