Mixed neuroendocrine-non-neuroendocrine neoplasms of the rectum: A case report

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Introduction: Mixed Neuroendocrine-Non-Neuroendocrine Neoplasms (MiNEN) represent roughly 1-2% of all colorectal malignancies. Given the rareness and heterogeneity of these mixed tumors, recognition and accurate diagnosis remain a challenge. In the absence of established guidelines, they are treated according to the standard of care for pure neuroendocrine carcinomas or adenocarcinomas from similar sites of origin.

Aim(s): The aim of this case report is to further our understanding regarding the clinical presentation, radiological features, pathology, management and prognosis of MiNEN.

Materials and methods: We herein report a case of a rectal MiNEN in a 55-year-old male. He underwent colonoscopy for rectal bleeding and mucus emission, which revealed a vegetating lesion located approximately 8 cm from the anal verge, corresponding to a moderately differentiated low-grade adenocarcinoma (ADC) of the rectum. Computed Tomography scan and Magnetic Resonance Imaging uncovered the presence of lung, lymph node and subcutaneous implants metastases. The biopsy of the cutaneous implant showed Neuroendocrine Carcinoma (NEC) Ki-67 90%.

Conference:

Presenting Author: Verdasca F

Authors: Verdasca F, Montenegro A, Mendes J, Furtado I, Ferreira R,

Keywords: mixed neuroendocrine-non-neuroendocrine neoplasms, mixed epithelial endocrine neoplasms, case report, colorectal cancer,