Synchronous primary neuroendocrine and mucinous epithelial tumors present in the same appendix. Case report of 2 patients

Case report: A rare case of coexistence of low-grade appendiceal mucinous neoplasia and goblet cell adenocarcinoma in the appendix

Background

Primary appendiceal tumors are rare. Low-grade appendiceal mucinous neoplasia (LAMN) and goblet cell adenocarcinoma (GCA) account for 20% and 14% of primary appendiceal tumors, respectively. The coexistence of LAMN and GCA is an extremely rare event. This report presents a case of an elderly male patient with an appendiceal tumor composed of LAMN and GCA in the same appendix.

Case presentation

A 72-year-old male patient was admitted to our institution presenting with a history of abdominal pain localized to the right lower quadrant for two months. Abdominal computed tomography (CT) showed a large dilated thickened cystic mass in the appendix, along with a small duodenal diverticulum. Laboratory tests indicated elevated levels of serum carcinoembryonic antigen (CEA) and cancer antigen 199 (CA19-9) markers. The patient underwent a laparoscopic right hemicolectomy and exploration of the duodenal diverticulum, and there was no finding of perforation of the duodenal diverticulum. Focal positivity for chromogranin A (CgA) and synaptophysin (Syn) was observed in the tumor cells of GCA. The final pathological diagnosis revealed the coexistence of LAMN staged pT4a and grade 1 GCA staged pT3 in the appendix. Unfortunately, the patient died due to severe septic shock and circulatory failure secondary to a perforated duodenal diverticulum.

Conclusions

The coexistence of LAMN and GCA are extremely rare in the appendix and may result from the proliferation of two independent cellular lines. The coexistence of distinct neoplasms poses diagnostic and management challenges. Multidisciplinary team discussion may be essential in the effective management of these patients.

Appendiceal collision tumors: case reports, management and literature review

Appendiceal tumors are incidentally detected in 0.5% cases of appendectomy for acute appendicitis and occur in approximately 1% of all appendectomies. Here, we report two cases of appendiceal collision tumors in two asymptomatic women. In both cases, imaging revealed right-lower-quadrant abdominal masses, which were laparoscopically resected. In both cases, histological examinations revealed an appendiceal collision tumor comprising a low-grade appendiceal mucinous neoplasm and well-differentiated neuroendocrine neoplasm (NEN). For complete oncological control, right hemicolectomy was performed in one patient for the aggressive behavior of NEN; however, histology revealed no metastasis. The other patient only underwent appendectomy. No further treatment was recommended. According to the latest guidelines, exact pathology needs to be defined. Proper management indicated by a multidisciplinary team is fundamental.

Collision tumor of the appendix incidentally discovered in a patient diagnosed with an adenocarcinoma of the colon: a case report

Collision tumor of the appendix is an extremely rare entity, defined as the coexistence of two independent tumors located in the same site without transitional changes. We describe in this report the case of a 75-year-old man who presented with an acute abdominal pain, nausea and vomiting. Physical examination revealed an abdominal distension with a hypogastric mass. Abdominal computed tomography showed colonic obstruction related to a sigmoid tumor. Therefore, a total colectomy was made. Macroscopic specimen examination showed a sigmoid tumor associated to a cystic dilatation of the appendix tip with mucoid content. Histological examination of the appendix showed the co-existence of two independent tumors located in the tip, without transitional changes: pTis low-grade appendiceal mucinous neoplasia and grade 1 neuroendocrine tumor. The latter was discovered incidentally during histological examination. We draw attention through our presentation to the importance of a thorough macroscopic and histological examination of the appendix.

A Low-Grade Appendiceal Mucinous Neoplasia and Neuroendocrine Appendiceal Collision Tumor: A Case Report and Review of the Literature

Patient: Female, 31-year-old

Final Diagnosis: Appendiceal neuroendocrine tumor • low-grade appendiceal mucinous neoplasm

Symptoms: Abdominal pain • dysuria

Medication: —

Clinical Procedure: Laparoscopic appendicectomy • laparoscopic right hemicolectomy

Specialty: Oncology • Surgery

Lights and darks of neuroendocrine tumors of the appendix

INTRODUCTION

Neuroendocrine tumors of the appendix are a relatively frequent type of neuroendocrine tumor, usually detected incidentally after appendectomy. Almost all small slow-growing G1 tumors with no risk factors are cured with appendectomy while the rare and aggressive G3 carcinomas may represent a challenge in terms of management and often lead to a poor outcome. In the middle of the spectrum, a number of tumors present with in-between features and sometimes no clear-cut guidance emerges from the literature for directing the management and follow-up of these patients.

EVIDENCE ACQUISITION

A meticulous review of the literature on neuroendocrine tumors of the appendix, including the recommendations published by the relevant international societies.

EVIDENCE SYNTHESIS

The literature on the neuroendocrine tumors of the appendix appears to be inhomogeneous. Likely this occurs as a consequence of a number of factors, including the mostly retrospective nature of the available data, the heterogeneous records of the same, and some peculiar aspects of the appendiceal neuroendocrine tumors, with evidence of considerable biological and clinical differences in terms of epidemiology, management, and prognosis from the less aggressive tumors to the most aggressive cancers. In particular, some situations concerning tumors in the middle of the biological and clinical spectrum are still poorly defined.

CONCLUSIONS

There are some persisting "grey areas" with regard to the characterization and the clinical management of neuroendocrine tumors of the appendix. An increasing awareness of the biological and clinical aspects of this disease and new, ideally prospective, focused studies might help and clarify some relevant issues that are not fully elucidated yet and could increase the solidity of the guidance for the management and the follow-up of the patients.