Gallbladder Neuroendocrine Neoplasms: A Case Report of Gallbladder Small Cell Carcinoma.

Abstract

Gallbladder (GB) carcinoma is the fifth most common gastrointestinal malignancy with 7000 new cases diagnosed in the USA each year [1]. The majority of these tumors are adenocarcinomas [2, 3]. Other histologic types of GB cancers include squamous, adenosquamous, and neuroendocrine carcinoma (NEC). The overall 5-year survival rate for gallbladder cancer is approximately 5 % [3]. Neuroendocrine tumors (NETs) commonly arise in gastrointestinal tracts and bronchi but rarely occur in the gallbladder (GB) [4]. Depending upon biological behavior, NETs are broadly classified as well-differentiated NETs (classical carcinoid tumors) or neuroendocrine tumor grade 1 (G1); welldifferentiated neuroendocrine carcinomas (atypical carcinoid) or grade 2 (G2); and poorly differentiated neuroendocrine carcinoma (large cell/small cell carcinoma or high-grade neuroendocrine carcinomas) or grade 3 (G3). High-grade neuroendocrine carcinomas are distinguished from typical carcinoids ( 20/10 hpf) [5]. Small cell carcinoma (SCC) of the gallbladder is a rare disease, with Surveillance, Epidemiology and End Results (SEER) data suggesting an incidence of approximately 0.5 % of all gallbladder cancers [6] and 0.2 % of all gastrointestinal carcinoid [7]. First SCC of gallbladder was reported in 1981 by AlboresSaavedra et al. [8]. Gallbladder neuroendocrine tumors may be functioning with symptoms arising due to the production of biologically active peptides (carcinoid syndrome <1 %). Conversely, they can be nonfunctioning with symptoms presenting due to mass effect and disease progression [3]. However, SCCs are generally nonfunctional tumors. This disease most commonly affects elderly female population and is associated with cholelithiasis and cigarette smoking [9]. Interestingly, there are no neuroectodermal cells in the gallbladdermucosa [10]. This had led investigators to postulate that the SCC arises from metaplastic epithelium of the gallbladder wall [11]. This hypothesis is supported by the presence of metaplasia in the gallbladder with chronic cholecystitis [12]. The symptomatology of gallbladder neuroendocrine tumors (GB-NETs) is nonspecific, and their diagnosis is often made at cholecystectomy for cholecystolithiasis or polyps [13]. Distant metastasis at presentation is present as much as 75% and is most often located in the liver and adjacent lymph nodes [3]. Here, we report one case of small cell carcinoma of the gallbladder treated at a tertiary care center (Ochsner Clinic Foundation, New Orleans, USA).