PREVALENCE OF ADENOMYOMA OF GALLBLADDER. ULTRASONOGRAPHIC AND HISTOLOGICAL ASSESSMENT IN A RETROSPECTIVE SERIES OF 450 CHOLECYSTECTOMIES.

BACKGROUND: Adenomyomas of the gallbladder are difficult to examine during standard ultrasound examination of the abdomen. They sometimes undergo malignant transformation and their optimal management still remains a problem. The authors have aimed to investigate the ultrasonographic and histopathological prevalence of gallbladder adenomyomas focusing on the diagnostic performance of ultrasound examination. MATERIALS AND METHODS: A retrospective series of 450 consecutive patients who underwent cholecystectomy is reported. Data regarding characteristics of the patients, US and histology examination of the gallbladder were collected. Sensitivity, specificity, positive and negative predictive values of ultrasound scan were calculated with respect to histological examination of the gallbladder. RESULTS: The study group consisted of 261 female and 189 male. Ultrasound scan detected adenomyomas in 22 patients, confirmed by histopathology in 13 and found to be not present in 9. Incidental adenomyomas were found in 16 patients of 428 who underwent cholecystectomy for gallstones. Prevalence was 4.9% and 6.4% for ultrasound scan and histopathology respectively. Ultrasound scan showed sensitivity of 43.3% (c.i.:25.4%-62.5%), specificity of 97.8% (c.i.:95.9%-99%) with a positive predictive value of 59% (c.i.:36.3%-79.2%) and with a negative predictive value of 96.2% (c.i.:93.7%-97.6%). On histopathology, adenomyomas localized in the fundus were predominant. Two female patients with adenomyomas of the fundus (diameter 5 mm) and single stone showed intestinal metaplasia with high-grade dysplasia. CONCLUSIONS: The diagnosis of gallbladder adenomyomas by ultrasound scan still remains a problem because of its low sensitivity, which is mainly due to the association with gallstones. Histopathological findings in the perilesional mucosa confirm the hypothesis of a metaplasia-dysplasia-carcinoma sequence already shown in the colon-rectum. At present, the selection of patients requiring cholecystectomy is still controversial.