Collision carcinoma of the rectum involving neuroendocrine carcinoma and adenocarcinoma: A case report

Mixed neuroendocrine-non-neuroendocrine neoplasm of the colon treated with laparoscopic resection and adjuvant chemotherapy: a case report

Mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN) of the colon is rare with a poor prognosis. Since the first description of a mixed neoplasm 100 years ago, the nomenclature has evolved, most recently with the 2022 World Health Organization (WHO) classification system. We describe our experience of a case of locoregionally advanced MiNEN of the descending colon treated with curative laparoscopic resection and adjuvant chemotherapy. The patient is a 72 year old woman who presented with haematochezia. Initial clinical diagnosis was poorly differentiated adenocarcinoma of the descending colon, cT2N0M0, cStage I. Laparoscopic partial colectomy of the descending colon with D3 lymph node dissection and intracorporeal overlap anastomosis was performed. The pathological diagnosis however, returned mixed adenocarcinoma-neuroendocrine carcinoma (MANEC) of the descending colon, pT4aN1bM0, pStage IIIB, a subgroup of MiNEN: 70% was neuroendocrine carcinoma (NEC), whilst poorly differentiated mucinous carcinoma constituted 30% of the tumour. She completed 4 courses of irinotecan plus cisplatin (IP) adjuvant chemotherapy and is currently recurrence-free at postoperative year 2. The clinical course of MiNEN depends on the biology of the two components, both of which must be pathologically characterised. Even quantitatively discrete components should be carefully subtyped as their prognostic relevance is undetermined.

Collision tumor of primary malignant lymphoma and adenocarcinoma in the colon diagnosed by molecular pathology: A case report and literature review

BACKGROUND

Collision tumors of primary malignant lymphoma and adenocarcinoma in the colon are rare. Primary diffuse large B-cell lymphoma (DLBCL)-adenocarcinoma collision tumors are especially rare.

CASE SUMMARY

A 74-year-old woman presented with abdominal pain of 1 mo duration. Biopsy under colonoscopy revealed adenocarcinoma of the ascending colon. Subsequently, the patient underwent laparoscopic radical resection of right colon cancer with lymph node dissection. A collision tumor was found incidentally through postoperative pathological sampling. Genetic analysis showed a collision tumor of DLBCL with germinal center B-cell subtype and TP53 mutation, and adenocarcinoma arising in a tubulovillous adenoma in the colon, with BRAF mutation and mutL homolog 1 promoter methylation. The patient died 3 mo after surgery. To our knowledge, this is the 23rd reported case of collision tumor of colorectal adenocarcinoma and lymphoma. The mean age of the 23 patients was 73 years. The most common site was the cecum. There were 15 cases with follow-up data including 11 living and four dead with a 3-year overall survival rate of 71.5%.

CONCLUSION

Based on pathological and genetic analysis, surgery combined with chemotherapy or chemoradiotherapy may have good therapeutic effects for collision tumor.