Hypoechoic area as an ultrasound finding suggesting subserosal invasion inpolypoid carcinoma of the gall bladder

Ultrasound studies have demonstrated the gall bladder wall to consist of tw o or more (usually three) layers. Gall bladder tumours with neither a thinn ed nor split outermost hyperechoic layer are confined to the mucosa or musc le layer, or have only invaded the shallow subserosa. Differentiation of th ese two types of tumour has posed difficulties. We report a case of polypoi d gall bladder carcinoma invading the shallow subserosa with a thickened ou termost hyperechoic layer but a hypoechoic area in the deeper part of the t umour. Ultrasound and pathological correlation in this case demonstrated th at the hypoechoic area represented an adenocarcinoma invading the subserosa accompanied by abundant fibrosis.