S2010 Colonic Carcinoma With Neuroendocrine Features Diagnosed in the Setting of Enterococcus faecalis Bacteremia, Endocarditis and Embolic Phenomenon

Abstract

Introduction: A 77-year-old man with a history of hypertension, hyperlipidemia, prior ischemic stroke, and chronic back pain presented with fever and confusion 3 days after undergoing a lumbar epidural steroid injection. Case Description/Methods: A 77-year-old man with a history of hypertension, hyperlipidemia, prior ischemic stroke, and chronic back pain presented with fever and confusion 3 days after undergoing a lumbar epidural steroid injection. Multiple sets of blood cultures grew Enterococcus faecalis. His CRP was elevated at 86. An MRI scan of the spine was negative for epidural abscess. Brain MRI revealed multiple acute embolic infarcts. Transthoracic echocardiography revealed a mobile 8mm vegetation, and transesophageal echocardiography confirmed mitral valve endocarditis. CT of the abdomen and pelvis revealed colonic wall thickening at the hepatic flexure with coexistent fat stranding and lymphadenopathy. Subsequent colonoscopy revealed a 1 cm solitary cratered ulcer with heaped up borders at the hepatic flexure (Figure A). Histopathology demonstrated a high-grade carcinoma immunophenotypically positive for colonic (CDX2+, SATB2+, CK20+, CK7-) and neuroendocrine differentiation (chromogranin+, synaptophysin+) (Figure C, D). The favored diagnosis was colonic high-grade neuroendocrine carcinoma, large cell type. PET/CT Dotatate scan was negative for uptake at the hepatic flexure reflecting poor differentiation of the carcinoma and lack of somatostatin receptors expression. Subsequent PET/CT FDG scan was positive reflecting high FDG avidity in the identified hepatic flexure hypermetabolic lesion, surrounding lymph nodes, and numerous hepatic lesions (Figure B). The patient was treated with antibiotics for endocarditis and started on carboplatin and etoposide. Discussion: Classically, Streptococcus bovis bacteremia and endocarditis are associated with colorectal cancer. Evidence is accumulating for a link between Enterococcus faecalis, a component of gut flora, and colorectal adenocarcinoma. The biopsies of the ulcerated mass at the hepatic flexure, in our patient with Enterococcus faecalis bacteremia and endocarditis, suggested a primary colonic neuroendocrine carcinoma, large cell type. Neuroendocrine tumors of the colon arise from enterochromaffin cells in the crypts of Lieberkuhn. Colon carcinoid tumors are rare, with an annual incidence of approximately 0.2 per 100,000. Most neuroendocrine tumors are asymptomatic at the time of diagnosis and often present with metastatic disease.Figure 1.: A: Colonoscopy revealing a 1 cm solitary cratered ulcer at the hepatic flexure. B: PET/CT FDG scan showing high FDG avidity at hepatic flexure. C: Histopathology H&E stain showing poorly differentiated carcinoma. D: Histopathology chromogranin stain positivity confirming neuroendocrine differentiation.