Metastatic small cell neuroendocrine carcinoma of the ileo-caecal junction presenting with tumour perforation - case report of a rare tumour at an unusual site with an uncommon presentation, and literature review

Neuroendocrine neoplasms (NEN) arise from neuroendocrine cells distributed in the lining epithelium of the lung, the gastro-intestinal tract (GIT) and genitourinary tract. They are classified into well-differentiated neuroendocrine tumours (NET) and poorly-differentiated neuroendocrine carcinoma (NEC), the latter including large-cell and small-cell variants. NECs are high-grade with aggressive histological features (high mitotic rate, extensive necrosis, and nuclear atypia). Most NECs are locally advanced or metastatic at diagnosis due to their inherent biological aggressiveness and therefore have a grim prognosis. Their peculiarity is characterised by the absence of features of carcinoid syndrome which typify their more differentiated counterparts. In this case report, we discuss a case of small cell neuroendocrine carcinoma (SmCC) of the ileo-caecal junction, a rather unusual site, in a 66-year-old male with multiple distant metastases and abdominal signs of perforation peritonitis with septic shock. He underwent emergency laparotomy and ileo-colic resection with a double-barrel enterostomy but succumbed to overall ill-health a fortnight later.