Neuroendocrine carcinoma of the gallbladder concomitant with adenocarcinoma of the sigmoid colon: A rare case report

INTRODUCTION AND IMPORTANCE: Neuroendocrine carcinoma of the gallbladder is rare and aggressive, its diagnosis is based on pathologic and immunohistochemical examination, currently there is no standard treatment for this tumor. Its concomitant occurrence with adenocarcinoma of the sigmoid colon is exceptional. CASE PRESENTATION: This case report describes a rare case of neuroendocrine carcinoma of the gallbladder that occurred concomitantly with sigmoid colon adenocarcinoma. The diagnosis of neuroendocrine carcinoma was established postoperatively by pathological and immunohistochemical examination. The biopsy of the colonic process confirmed the preoperative diagnosis. A laparotomy found a vesicular fundus process, peri-hilar adenopathy, metastasis of the liver segment V, and a sigmoid colon process. The patient underwent a cholecystectomy extended to segments IVb and V, with lymph node dissection and sigmoid colectomy. The postoperative follow-up was uneventful, and the length of hospitalization was seven days. The patient is currently undergoing adjuvant chemotherapy. DISCUSSION: Neuroendocrine carcinoma of the gallbladder is extremely rare, with few case reports, its occurrence concomitantly with adenocarcinoma of the sigmoid colon is exceptional. Histology and immunohistochemistry confirm the diagnosis, surgery is essential in the management of patients affected by this tumor. The presence of synchronous metastases causes doubt about their primitive, hence the primordial place of surgery and histological examination to adopt adequate management of the patients. CONCLUSION: We underline the rarity of this neuroendocrine tumor and the importance of histology and surgery in its management.