Incidental appendiceal mass as the only manifestation of endometriosis.

Appendiceal endometriosis is a rare condition that remains difficult to diagnose preoperatively. Herein, we present a case of appendiceal endometriosis presenting as a neuroendocrine tumor. A 34-year-old Caucasian woman was found to have an appendiceal mass with a small fluid collection on routine transvaginal ultrasound. The patient denied any symptoms. Features were consistent with those of a neuroendocrine tumour of the appendix. Laparoscopic appendectomy followed by histopathology revealed endometriosis with negative cytology for malignant cells. Preoperative characteristics of appendiceal tumours in women of childbearing age should be further investigated. Establishing clinical and surgical guidelines is the key to avoid invasive procedures and related adverse outcomes.