Am J Surg Pathol  2001 May;25(5):595-601 

Small cell carcinoma of the gallbladder: a clinicopathologic,
immunohistochemical, and molecular pathology study of 12 cases.

Maitra A, Tascilar M, Hruban RH, Offerhaus GJ, Albores-Saavedra J.

Departments of Pathology, University of Texas Southwestern Medical Center,
Dallas, Texas, USA.

Small cell carcinomas of the gallbladder are unusual neoplasms that have been
characterized only recently. The authors describe the clinical, histopathologic,
immunohistochemical, and molecular features of 12 small cell carcinomas of the
gallbladder. The mean age at diagnosis was 69 years, and the male-to-female
ratio was 5:7. The neoplasms had an average size of 3 cm, and 90% showed
invasion of the muscularis propria and perimuscular connective tissue.
Seventy-five percent of the carcinomas had metastasized or extended locally
beyond the gallbladder at surgery. Survival was uniformly poor, with a mean
survival of 10.7 months (range, 3-25 months). Half the small cell carcinomas
were combined with other neoplasms. Four had foci of adenocarcinoma, one
contained areas of squamous differentiation, and another had a component of
carcinosarcoma. Immunohistochemical analysis showed focal reactivity for
chromogranin (six of six cases), neuron-specific enolase (six of six cases), and
Leu-7 (three of three cases). The molecular changes in small cell carcinomas
were similar to those of adenocarcinomas occurring at this site, with a high
frequency of p53 (75%) and p16INK4a (33%) abnormalities, and a low frequency of
deleted in pancreatic carcinoma-4 inactivation (0%) and K-ras codon 12 mutations
(17%). In contrast to pulmonary small cell carcinomas, p16INK4a function appears
to be abrogated more frequently in these carcinomas.

PMID: 11342770 [PubMed - indexed for MEDLINE]