Surgical guidelines for appendiceal neuroendocrine tumors; remarkable histopathology result supports guidelines of evidence-based medicine

Posted on by admin

LETTER

Hippokratia 2024, 28(3): 134

Gkaitatzi D, Anastasiadis P, Giakoustidis A
1st Department of Surgery, “Papageorgiou” General Hospital, School of Medicine, Aristotle University of Thessaloniki,
Thessaloniki, Greece

Keywords:  Appendiceal, neuroendocrine, tumors, appendectomy, hemicolectomy

Corresponding author: Ass.Prof. Alexandros Giakoustidis, 1st Department of Surgery, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece, e-mail: alexgiakoustidis@gmail.com

Dear Editor,

Neuroendocrine tumors (NETs) are well-differentiated carcinomas that usually occur along the gastrointestinal tract, with 17 % in the appendix1-3 representing approximately 85 % of all appendiceal neoplasms2. Appendiceal NETs (aNETs) are diagnosed in 0.2-0.7 % of all histopathological examinations of appendectomy specimens1-3, and 60-70 % are located at the tip, 5-23 % in the body, and 7-10 % at the base of the appendix1-3. There is a higher incidence in younger patients (32-42 years)1,3, and in 50 % of cases, aNETs are presented as acute appendicitis1-3. Localization is significant for prognosis as incomplete resection is most likely to occur at the base of the appendix and is in jeopardy of developing local recurrence2,3. Approximately 95 % of aNETs are <2 cm; 60-85 % <1 cm, 5-25 % 1-2 cm, and 2-17 % >2 cm1. The risk of metastases in tumors <1 cm is less than 1 %, and these tumors are cured by a simple appendectomy1,2. Tumors between 1-2 cm are more likely to develop metastasis1. Therefore, there are two procedures, simple appendectomy and right hemicolectomy1,2, that can be performed after considering other prognostic factors (e.g., involvement of mesoappendix, elevated Ki67 level, tumor location, Chromogranin A biomarker, lymph node metastasis, or other metastatic sites)1,3. Tumors larger than two cm are rare but pose a risk of lymph node metastasis around 20-85 %, and therefore are treated with right hemicolectomy1,2. A simple appendectomy is curative and sufficient for aNETs <1 cm with invasion of the subserosa or mesoappendiceal invasion up to 3 mm and clear surgical margins. Tumors at the base of the appendix, tumors of 1-2 cm, and tumors with margin invasion or deep mesoappendiceal invasion hold a relevant risk of recurrence. Therefore, right hemicolectomy is recommended2,3. For aNETs larger than two cm with or without extensive mesoappendiceal invasion (≥3 mm) or margin invasion, right hemicolectomy is indicated2,3.

A 23-year-old female presented in the emergency department with right iliac fossa pain and nausea. She had leukocytosis, and the abdominal ultrasound indicated dilatation of the appendix. A laparoscopic appendectomy was performed, and histopathological analysis of the excised specimen showed a tumor at the tip of the appendix, sized >2 cm, and infiltration of the subserosa and the mesentery >3 mm. These findings indicated a NET grade 1 (carcinoid), according to the American Joint Committee on Cancer (AJCC) and the International Union Against Cancer (UICC), 2017. Therefore, a computed tomography scan and an Octreoscan were performed, without any pathological findings. Due to the size of the tumor and the infiltration of the mesentery, a laparoscopic right hemicolectomy was decided by the Multi-Disciplinary Team Meeting and performed with an excellent postoperative course. The pathological examination of the removed colon revealed a lymph node metastasis in one of 22 pericolic lymph nodes, with isolated tumor cells positive for CD56 and chromogranin A.

There are two classification systems for aNETs: the European Neuroendocrine Tumor Society (ENETS) and AJCC3. Tumor size is the most important indicator regarding surgical approach and prognosis. For T2 (UICC/AJCC), T3 (ENETS), or higher-stage NET (>2 cm), due to the increased risk of lymph node metastasis and long-term recurrence, right hemicolectomy with lymph node dissection is recommended3. The imaging tests performed showed no pathological findings, and even though the histopathological examination showed negative lymph nodes, isolated tumor cells were present. The combination of these results underlines the importance of following the official guidelines. The management of aNETs is a challenging clinical situation because the risk of recurrence may be low, but its consequence is significant.

Conflict of interest

None.

References

  1. Alexandraki KI, Kaltsas GA, Grozinsky-Glasberg S, Chatzellis E, Grossman AB. Appendiceal neuroendocrine neoplasms: diagnosis and management. Endocr Relat Cancer. 2016; 23: R27-R41.
  2. Grozinsky-Glasberg S, Alexandraki KI, Barak D, Doviner V, Reissman P, Kaltsas GA, et al. Current size criteria for the management of neuroendocrine tumors of the appendix: are they valid? Clinical experience and review of the literature. Neuroendocrinology. 2013; 98: 31-37.
  3. Neto Sa Silva Abreu R. Appendiceal neuroendocrine tumors: approach and treatment. J Coloproctol. 2018; 38: 337-342.