Morphological features of early gallbladder carcinoma.

ABSTRACT

BACKGROUND/AIMS: This study aimed to clarify the morphological features of early gallbladder carcinoma including tumors invading the lamina propria (pT1a) or muscular layer (pT1b). METHODOLOGY: This retrospective study involved 299 patients with early gallbladder carcinomas, identified from a surgical pathology database covering 29 years from 1982 through 2010. The macroscopic appearance of the tumor was classified as protruding (n=107, 36%) or superficial (n=192, 64%). Protruding tumors were subdivided into pedunculated or sessile, whereas superficial tumors were subdivided into elevated, flat or depressed. RESULTS: Eighty-four of 107 protruding tumors (79%) were detected preoperatively and/or intraoperatively, whereas only 47 of 192 superficial tumors (24%) were detected in this manner (p<0.001). Of the 107 protruding tumors, 21 were pedunculated and 86 were sessile; 76 of these sessile tumors (88%) were accompanied by superficial elevated and/or flat tumors. In total, 257 patients (86%) had pT1a tumors and 42 (14%) had pT1b tumors. No patient had evidence of lymphatic/blood vessel or perineural invasion or nodal metastasis on histology, except for lymphatic vessel invasion in one patient with a pT1b tumor. CONCLUSIONS: Two-thirds of early gallbladder carcinomas are classified as superficial. Most pT1b gallbladder carcinomas spread only locally.