[A Case Report of Rectal MiNEN Laparoscopic Resection]

Area of Science:

• Gastroenterology
• Oncology
• Pathology

Background:

• Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNEN) are rare gastrointestinal tumors with limited data on optimal treatment strategies.
• Early detection and accurate diagnosis are crucial for managing MiNEN, given their potential for aggressive behavior and poor prognosis.

Observation:

• A 74-year-old woman presented with a positive fecal occult blood test, leading to colonoscopy.
• Colonoscopy identified a Type 1 tumor in the rectosigmoid region, diagnosed as well-differentiated adenocarcinoma (tub1) on biopsy.
• Post-surgical pathological analysis revealed a MiNEN (adenocarcinoma:NEC ratio of 6:4) staged as pT4a, pN2a, Stage IIIC, with all lymph node metastases originating from the NEC component.

Findings:

• The final pathological diagnosis was a mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN) with a significant neuroendocrine carcinoma (NEC) component in lymph node metastases.
• The tumor's characteristics and nodal involvement indicated a high risk of recurrence.
• The patient was referred for adjuvant chemotherapy with carboplatin and etoposide, a regimen often used for NEC.

Implications:

• This case underscores the importance of recognizing the NEC component in MiNEN for guiding adjuvant therapy decisions.
• Accumulating more case studies and evidence is essential for developing effective therapeutic strategies for MiNEN.
• Further research into the specific behavior and treatment of MiNEN is warranted to improve patient outcomes.