Non-neoplastic Polyps of the Gallbladder: A Clinicopathologic Analysis of 447 Cases.

There is no systematic histopathologic analysis of non-neoplastic polyps in the gallbladder. In this study, in addition to a computer search for cases designated as "polyp," a systematic review of 2533 consecutive routinely sampled archival and 203 totally submitted prospective cholecystectomies were analyzed for >2 mm polyps (cut-off was based on radiologic sensitivity). A total of 447 non-neoplastic polyps were identified. The frequency was 3% in archival cases and 5% in totally submitted cases. Only 21 (5%) were ≥1 cm. The average age was 52 years, and the female to male ratio was 3.1. Two distinct categories were delineated: (1) injury-related polyps (n=273): (a) Fibro(myo)glandular polyps (n=214) were small (mean=0.4 cm), broad-based, often multiple (45%), almost always (98%) gallstone-associated, and were composed of a mixture of (myo)fibroblastic tissue/lobular glandular units with chronic cholecystitis. Dysplasia seen in 9% seemed to be secondary involvement. (b) Metaplastic pyloric glands forming polypoid collections (n=42). (c) Inflammatory-type polyps associated with acute/subacute injury (11 granulation tissue, 3 xanthogranulomatous, 3 lymphoid). (2) Cholesterol polyps (n=174) occurred in uninjured gallbladders, revealing a very thin stalk, edematous cores devoid of glands but with cholesterol-laden macrophages in 85%, and cholesterolosis in the uninvolved mucosa in 60%. Focal low-grade dysplasia was seen in 3%, always confined to the polyp, unaccompanied by carcinoma. In conclusion, non-neoplastic polyps are seen in 3% of cholecystectomies and are often small. Injury-related fibromyoglandular polyps are the most common. Cholesterol polyps have distinctive cauliflower architecture, often in a background of uninjured gallbladders with cholesterolosis and may lack the cholesterol-laden macrophages in the polyp itself. Although dysplastic changes can involve non-neoplastic polyps, they do not seem to be the cause of invasive carcinoma by themselves.

Squamous cell and adenosquamous carcinomas of the gallbladder: clinicopathological analysis of 34 cases identified in 606 carcinomas.

The information in the literature on squamous cell and adenosquamous carcinomas of the gallbladder is highly limited. In this study, 606 resected invasive gallbladder carcinoma cases were analyzed. Squamous differentiation was identified in 41 cases (7%). Those without any identifiable glandular-type invasive component were classified as pure squamous cell carcinomas (8 cases) and those with the squamous component constituting 25-99% of the tumors were classified as adenosquamous carcinomas (26 cases) and included into the analysis. The remaining 7 that had <25% squamous component were classified as adenocarcinoma with focal squamous change and excluded. The clinicopathological characteristics of adenosquamous carcinoma/squamous cell carcinomas were documented and contrasted with that of ordinary gallbladder adenocarcinomas. The average patient age was 65 years (range 26-81); female/male ratio, 3.8. In only 13%, there was a preoperative clinical suspicion of malignancy. Grossly, 58% presented as thickening and hardening of the wall and 6% were polypoid. In 12%, mucosa adjacent to the tumor revealed squamous metaplasia. All pure squamous cell carcinomas had prominent keratinization. Giant cells and tumor-infiltrating eosinophils were observed in 29 and 51% of the squamous cell carcinomas/adenosquamous carcinomas versus 10% (P=0.02) and 6% (P=0.001) in gallbladder adenocarcinomas, respectively. All but three cases had 'advanced' (pT2 and above) carcinomas. Follow-up was available in 31 patients: 25 died of disease (median=5 months, range 0-20), and 6 were alive (median=64 months, range 5-112.5). The survival of patients with squamous cell carcinomas/adenosquamous carcinomas was significantly worse than that of gallbladder adenocarcinomas (P=0.003), and this adverse prognosis persisted when compared with stage-matched advanced gallbladder adenocarcinoma cases (median=11.4 months, P=0.01). In conclusion, squamous differentiation was noted in 7% of gallbladder carcinomas. The incidence of adenosquamous carcinoma (defined as 25-99% of the tumor being squamous) was 4%, and that of pure squamous cell carcinoma (without any documented invasive glandular component) was 1%. Pure squamous cell carcinomas often showed prominent keratinization. The overall prognosis of adenosquamous carcinoma/squamous cell carcinoma appears to be even worse than that of ordinary adenocarcinomas. Most patients died within a few months; however, those few who were alive beyond 2 years in this cohort experienced long-term survival.