Analysis of the nature and associations of adenomyomas of the gallbladder
The nature and clinicopathologic associations of gallbladder adenomyoma are controversial. Some studies have attributed up to 26 percent of gallbladder carcinomas to adenomyomas. The authors conducted a study to examine the frequency, clinicopathologic characteristics, and neoplastic changes in gallbladder adenomyoma (GB AM). Cases from five cholecystectomy cohorts were identified: 1,953 consecutive specimens prospectively subjected to gross examination, with specific attention to AM; 2,347 archival specimens; 203 totally embedded GBs; 207 cholecystectomies with primary GB invasive carcinoma; and a computer search of participating institutions for all archival cases diagnosed as AM that were not captured in the aforementioned cohorts. Frequency of AM was 9.3 percent (19 of 203) in fully submitted cases but 3.3 percent (77 of 2,347) in routinely sampled archival tissue. A total of 283 AMs were identified, with a female-to-male ratio of 1.9 (177:94) and mean size of 1.3 cm (range, 0.3–5.9). Ninety-six percent (203 of 210) were fundic, with formed nodular trabeculated submucosal thickening. Four of 257 (1.6 percent) were multifocal, and three of 257 (1.2 percent) were extensive (that is, adenomyomatosis). Dilated glands (up to 14 mm), often radially converging to a point in the mucosa, were typical. Muscle was often minimal and confined to the upper segment. Nine of 225 (four percent) revealed features of a duplication. No specific associations with inflammation, cholesterolosis, intestinal metaplasia, or thickening of the uninvolved GB wall were identified. Neoplastic change arising in AM was seen in 9.9 percent (28 of 283). Sixteen of 283 (5.6 percent) had mural intracholecystic neoplasm. Seven of 283 (2.5 percent) had flat-type high-grade dysplasia/carcinoma in situ. Thirteen of 283 (4.6 percent) cases had AM and invasive carcinoma. However, carcinoma arose from AM in only five of 283 (1.8 percent). (Invasion was confined to AM, and dysplasia was predominantly in AM.) The authors concluded that AMs have all the features of a malformative developmental lesion and may not show a significant muscle component, so the name adenomyoma is partly a misnomer. While most are innocuous, some pathologies may arise in AMs, including intracholecystic neoplasms, flat-type high-grade dysplasia or carcinoma in situ, and invasive carcinoma. It is recommended that gross examination of GBs include serial slicing of the fundus to detect AM and total submission of the GB if AM is found.
Dursun N, Memis B, Pehlivanoglu B, et al. Adenomyomas of the gallbladder: An analysis of frequency, clinicopathologic associations, and relationship to carcinoma of a malformative lesion. Arch Pathol Lab Med. 2024;148(2):206–214.
Correspondence: Dr. N. Volkan Adsay at vadsay@kuh.ku.edu.tr