Reliability of frozen section diagnosis of gallbladder tumor for detecting carcinoma and depth of its invasion.

BACKGROUND

An accurate frozen section diagnosis is important when deciding the surgical strategy against a gallbladder tumor intraoperatively. Little has been reported on the accuracy of frozen section diagnosis of the gallbladder.

PATIENTS AND METHODS

In a total of 86 consecutive patients with gallbladder tumor, the accuracy of the frozen section diagnosis was examined. There were 32 patients with polypoid lesions and 54 with nonpolypoid tumors.

RESULTS

The frozen tissue diagnosis and final diagnosis were identical in 82 of the 86 cases, that is, benign in 65 and malignant in 17. The other four cases had different diagnoses, that is, conversion from benign to malignant in two and from malignant to benign in two. The overall accuracy of frozen diagnosis was 95.3% (97.0% for benign and 94.7% for malignant). In 32 polypoid lesions, the accuracy of frozen section diagnosis was 91% (93% for benign; 89% for malignant). In 54 nonpolypoid lesions, the accuracy of diagnosis was 98% (100% for benign; 93% for malignant). The diagnosis of depth of invasion was identical only in 7 (70%) of the 10 carcinoma cases examined, while it was diverse in the remaining 3, that is, conversion from adenocarcinoma invading the subserosa to that limiting to the mucosa in one, from carcinoma within the mucosa to that infiltrating the muscle coat in one, and from carcinoma affecting the muscle layer to that invading the subserosa in the other. Alterations of frozen section diagnosis about being benign or malignant and about the depth of invasion were encountered in seven patients, five of whom had a polypoid tumor.

CONCLUSIONS

The intraoperative frozen tissue diagnosis is fairly reliable as to whether lesions are malignant or benign; however, accuracy is low in patients with polypoid lesions of the gallbladder. Also, frozen section diagnosis does not reliably measure the depth of invasion of gallbladder carcinoma.