Peritoneal dissemination of appendiceal goblet cell adenocarcinoma mimicking white pus caused by peritonitis following appendicitis: an instructive case report

Abstract

Background: Goblet cell adenocarcinoma is an extremely rare tumor in which the same cells exhibit both mucinous and neuroendocrine differentiation. It is considered more aggressive compared to conventional carcinoids and more likely to cause metastasis.

Case presentation: We report a case of goblet cell adenocarcinoma with peritoneal metastases. A 62-year-old man underwent appendectomy for acute appendicitis. Intraoperatively, inflammatory white pus and a small amount of dirty ascites were observed in the lower abdomen with severely inflamed appendix. Histopathological examination of the specimen collected during appendectomy revealed goblet cell adenocarcinoma with a positive surgical margin. One month later, additional ileal resection was planned. Laparoscopic examination revealed disseminated nodules throughout the abdominal cavity. Therefore, the patient underwent resection of the peritoneal nodules. The peritoneal specimens confirmed the histopathological findings. Thus we diagnosed the patient with peritoneal dissemination of appendiceal goblet cell adenocarcinoma.

Conclusions: In cases wherein white pus is observed during surgery for acute appendicitis, considering the possibility of dissemination, collecting samples for histopathological examination, and initiating early treatment are crucial.

Keywords: Appendiceal tumor; Goblet cell adenocarcinoma; Peritoneal dissemination.

Fig. 1

Abdominal computed tomography reveals acute appendicitis with swelling at the tip of the appendix and surrounding edema (yellow arrow)

Fig. 2

a Intraoperatively, inflammatory white pus (white arrow) and adhesions are apparent in the lower abdominal region. b Appendectomy is completed using two endoloops at the root of the appendix

Fig. 3

a, b Macroscopic view of the resected specimen, which is a 40- × 11- × 6-mm lesion with a positive margin

Fig. 4

Histopathological findings of the appendix lesion. a, b Hematoxylin and eosin (H&E) staining shows tumor cells with small lumina comprising goblet-like cells, and some tumor cell clusters lack lumina and appear as small groups of cohesive goblet-like cells. Low-grade patterns comprised less than 50%. c–e Immunohistochemical staining indicates that the tumor cells are positive for cytokeratin AE₁/AE₃ (c), and various number of endocrine cells are positive for chromogranin A (d), and synaptophysin (e)

Fig. 5

Intraoperative laparoscopic findings. White nodules are seen on the mesentery (white arrow)