Nese Ekinci1 , Eylül Gün1 , Arzu Avcı1 , Ahmet Er2

1Department of Pathology, İzmir Katip Çelebi University, Atatürk Training and Research Hospital, İzmir, Turkey
2Department of General Surgery, İzmir Katip Çelebi University, Atatürk Training and Research Hospital, İzmir, Turkey


Neoplasms of the appendix are very rare. They usually show glandular or neuroendocrine differentiation, and when they both occur in the same area, it is called a “collision tumor.” Low-grade mucinous neoplasms associated with appendiceal diverticula are also uncommon. The appendectomy specimen of a 60-year-old man contained dense and mucoid luminal content on the distal tip, and similarly a solid, yellow, lumen-obscuring tumor with a diameter of 1.5 cm at the base of the appendix was detected. Microscopically, there were three diverticula that comprised herniation of the mucosal layer through the appendiceal wall. Interestingly, all of the diverticula and the normal-appearing appendiceal wall were lined by adenomatous epithelium. The luminal portion had pools of mucin-containing, rare clusters of low-grade epithelium that gave rise to the diagnosis of a “low-grade mucinous neoplasm.” The solid-appearing tumor was diagnosed as a “neuroendocrine neoplasm,” and there was no transition zone between these two types of tumors. There are some cases that have been reported as low-grade mucinous neoplasms associated with appendicular diverticula and collision tumors consisting both mucinous neoplasms and carcinoid tumors in the literature; our case has a unique appearance with two different types of tumors both in the appendix wall and within multiple diverticula.

Keywords: Appendix, mucinous neoplasm, carcinoid, diverticuli

Cite this article as: Ekinci N, Gün E, Avcı A, Er A. ACoexistence of low-grade mucinous neoplasm and carcinoid (collision tumor) within multiple appendiceal diverticula: a case report. Turk J Surg 2021; 37 (3): 303-306.


Peer Review

Externally peer-reviewed.

Author Contributions

Concept - N.E., E.G.; Design - N.E., E.G.; Supervision - N.E.; Resource - N.E., E.G., A.E.; Materials - N.E., A.A., A.E.; Data Collection and/or Processing - N.E., E.G.; Analysis and/or Interpretation - N.E., E.G.; Literature Search - E.G., A.A.; Writing Manuscript - E.G., N.E.; Critical Reviews - N.E., A.A., A.E.

Conflict of Interest

The authors have no conflicts of interest to declare.

Financial Disclosure

The authors declared that this study has received no financial support.