Appendiceal Neuroendocrine Neoplasms diagnosed during Pregnancy-Case Series and Review of the Literature

Introduction:
Although appendicitis occurs in approximately 1:1000 pregnancies, appendiceal neuroendocrine neoplasm (ANEN) diagnosis during pregnancy is very rare. Data on presentation, treatment and prognosis is scarce.

Aim:
To describe ANEN cases diagnosed during pregnancy.

Materials and Methods a retrospective appraisal of 7 consecutive ANEN patients diagnosed during pregnancy from four Israeli tertiary medical centers and comparison with 17 cases described in the literature from 1965-2021.

Results:
Age at ANEN diagnosis was 26.4±3.5 years (range 21-33). Patients were diagnosed between gestational weeks 6-40, most frequently in the third trimester (53%). The most common presenting symptom was abdominal pain.

Tumor size was 14.3±8.9mm (range 3-45mm). In patients from our series appendiceal base involvement was reported in 2/7; mesoappendiceal invasion in 5/7; lympho-vascular invasion in 2/7. KI-67 staining was reported in 6/7 cases and ranged from 1-10%. Pathology details were lacking in most of the previously published cases.

All 7 pregnancies in our series resulted in term delivery with no complications, whereas in historical cases there were one first trimester abortion, one ectopic pregnancy, and one stillbirth.

Right hemicolectomy was performed in 5/7 patients in our series and reported in 2/17 historical cases. All hemicolectomies were performed after delivery, 3-16 months after appendectomy. Local metastases were reported in two cases. Follow-up duration was 7-98 months in our patients and 3-48 months in 5 previous cases. No disease recurrence, distant metastases or mortality were noted.

Conclusions:
ANEN diagnosis during pregnancy is extremely rare. Pregnancy outcomes were usually favorable and long-term prognosis was excellent.