S3909 Small Cell Carcinoma of the Cecum With Liver Metastasis

Introduction: Extrapulmonary small cell carcinoma (EPSCC) is an aggressive and rare form of neuroendocrine carcinoma characterized by a high mitotic index. The gastrointestinal (GI) tract accounts for 20%-25% of all ESPCCs with the esophagus being the most common site. The overall 5-year survival rate for EPSCC with metastasis is <5% even with systemic therapy. Here we present a case of biopsy-proven small cell carcinoma of the cecum with metastasis to the liver. Case Description/Methods: A 50-year-old woman with no past endoscopic evaluation and history of Helicobacter pylori status post confirmed eradication who initially presented with 20-pounds unintentional weight loss, weakness, and abdominal pain, as well as a liver biopsy 1-week prior revealing small cell carcinoma. She had no signs of overt GI bleeding. Patient recently presented to another facility and was found to be anemic requiring transfusion, and imaging had shown multiple liver lesions prompting the liver biopsy. During our encounter, the patient was again severely anemic requiring transfusion, with a Hgb of 4.2 g/dL on admission. Computed tomography imaging confirmed multifocal liver lesions and lymphadenopathy most pronounced in the periaortic, retroperitoneal, and pericecal areas. Esophagogastroduodenoscopy and colonoscopy were performed which revealed a hiatal hernia, gastritis, hemorrhoids, and cecal mass. Biopsy of this cecal mass confirmed small cell carcinoma with immunostains positive for synaptophysin, CD56, and CDX-2. Ki-67 proliferation index was >90%. After consultation with oncology, carboplatin and etoposide were initiated. Discussion: Although small cell carcinoma is most commonly associated with the lungs, EPSCC is a rare but important consideration. Involvement of the GI tract is uncommon, and usually reported in the esophagus, stomach, gallbladder, and rarely the colon when it is diagnosed. This case report highlights the rarity of small cell carcinoma of the cecum with metastasis to the liver, and emphasizes the benefit of endoscopic evaluation in metastatic liver lesions without a clear primary source. Further research is needed to better understand the incidence, prevalence, pathophysiology, prognosis, and treatment of cecal small cell carcinoma.