Adenocarcinoid: A rare primary appendiceal malignancy - Report of two cases and literature review

Adenocarcinoid of the appendix is a rare tumor which shares the histologic features of both conventional carcinoid and adenocarcinoma. Clinically, it usually presents as an acute appendicitis. Other manifestations such as chronic abdominal pain, palpable abdominal mass or asymptomatic progress have been reported. Surgery is the first choice of treatment, but preoperative diagnosis is nearly impossible. Two cases of appendiceal adenocarcinoid with different clinical manifestations are reported in this article. The first patient underwent appendectomy under the diagnosis of acute appendicitis. The pathologic finding was an adenocarcinoid, and the stump of the appendix was invaded by tumor cells. A subsequent operation of right hemicolectomy was then performed. The second patient presented as mechanical ileus, and laparotomy was carried out. A right hemicolectomy was done because of the obstruction of the terminal ileum. The pathologic examination revealed adenocarcinoid of appendix with terminal ileum invasion. To present knowledge, no similar cases have previously been reported in the English literature. Whether simple appendectomy or right hemicolectomy is the more appropriate surgery for appendiceal adenocarcinoid is still controversial. Some parameters such as extensive invasion, mitotic feature and cellular atypia were proposed to predict the aggressive potential of the tumors, and these gave some direction toward the decision of the surgical procedure.