Collision Tumor of the Appendix

Collision tumor of the appendix with concomitant cecal adenocarcinoma: A case report and literature review

INTRODUCTION

Collision tumors of the appendix are rare tumors consisting of two distinct pathologies arising from different cell lines simultaneously. The most common type is the coexistence of a neuroendocrine tumor (NET) with a low-grade appendiceal mucinous neoplasm (LAMN). We report a unique case of appendiceal collision tumor with synchronous cecal intra-mucosal carcinoma and pulmonary sarcoidosis.

CASE PRESENTATION

A 57-year-old man presented to the clinic with vague abdominal pain. Upon investigation, a colonoscopy showed a large cecal mass, and a computed tomography scan showed a polypoid cecal mass, a dilated, fluid-filled appendix, multiple bi-lobar lung nodules, and enlarged mediastinal and hilar lymph nodes (LN). Following discussion in a multi-disciplinary team tumor board meeting, the patient underwent laparoscopic right hemicolectomy and mediastinoscopy with mediastinal LN biopsy. His postoperative hospital stay was uneventful. Histopathology revealed a cecal tubulovillous adenoma with intra-mucosal carcinoma. A collision tumor of the appendix was found, including an in situ LAMN and a < 5 mm NET. The mediastinal LN showed sarcoidosis. There was no evidence of recurrence after a two-year follow-up.

DISCUSSION

Previous reports of appendicular collision tumors show high variability in the presentation and management. While some present with acute appendicitis, others may have a subacute or atypical presentation. Management ranges from appendectomy to cytoreductive surgery and hyperthermic intraperitoneal chemotherapy, depending on the tumor stage.

CONCLUSION

Collision tumors of the appendix are rare, with highly variable presentation and management. There are no clear management or surveillance guidelines, given their rarity. Thus, treatment should be individualized.

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.