Examination of Gallbladders at Military Treatment Facilities: Is Histologic Analysis Necessary?

Introduction: Gallbladder specimens from cholecystectomy procedures are a common specimen evaluated by military pathologists. These are often removed for inflammatory causes. Previous studies show that the incidence of gallbladder carcinoma (GBC) is around 3%. Incidentally identified GBC is even less common at 0.36%. Incidentally found GBCs are of little clinical consequence as most are treated by cholecystectomy alone. We hypothesize that a selective approach to histologic evaluation of gallbladders could save time for pathologists to focus on more complex cancer cases and save money for the Defense Health Agency. We propose that for patients under 50 years of age with no clinical or macroscopic concern for neoplasia, histologic evaluation may be omitted with negligible risk of missing a clinically relevant diagnosis.

Materials and methods: This protocol was determined to be institutional review board exempt. All pathology reports from cholecystectomies from January 1, 1998, to August 11, 2023 were pulled. Key data from these reports were extracted. These data include age, gender, and if there was a clinical or macroscopic concern for neoplasia, macroscopic findings, and histologic findings. Additionally, the patient's active duty status was pulled from Military Health Systems Genesis and the Joint Longitudinal Viewer and included for demographic data.

Results: Of 9,774 cases pulled, 2,063 of these reports underwent data extraction. In total, 63 cases were excluded, and 2,000 cases were sent to the 59th Medical Wing biostatistics department for analysis. In this dataset, there were 8 instances of malignancy, 5 of which were GBC (1 of these 5 arose from an intracholecystic papillary neoplasm), 2 of which were metastatic disease, and 1 a neuroendocrine tumor. The incidence of GBC in our dataset is 0.20%, lower than that of other studies. The sensitivity of a clinical/macroscopic concern to identify malignancy in a patient aged under 50 years is 66.67%. In the 187 cases from the active duty population, there were zero instances of dysplasia or malignancy.

Conclusions: The sensitivity of a clinical/macroscopic concern for neoplasia in a patient aged under 50 years is low, identifying only 2 of 3 malignancies in our dataset. However, the case that would have been missed under our proposed guidelines was from metastatic disease of a previously known metastatic malignancy. We consider that if a selective histologic evaluation is established, a history of malignancy should be a qualifier for evaluation regardless of any other factors. A selective approach to histologic evaluation of gallbladders could save our institution $4,716 to $5,240 annually. Additional studies, incorporating prior malignancy as a qualifier, are warranted to further evaluate the potential for harm in patients aged under 50 years and a number needed to harm should be established prior to any changes in practice.