1478 Small Cell Carcinoma of the Cecum: A Rare Entity

Abstract

INTRODUCTION: Small-cell carcinoma of the colon (SmCC) is a very rare disease and is difficult to achieve long-term survival due to its aggressive behavior. Distant metastases are often found at the time of diagnosis of tumor. High recurrence rates contribute to poor survival with a median survival of 10.5 months. The World Health Organisation (WHO) in 2010 classified SmCC as a subgroup of neuroendocrine carcinoma (NEC) which accounts for approximately 0.6 percent of all colorectal cancers. Peak incidence of these tumours is in the sixth and seventh decades of life. The limited information on colorectal small cell carcinoma in the literature shows that these tumors have similar demographic features to colorectal adenocarcinomas with the exception of being more common in females. Of note, cecal small cell carcinoma is even more rare. CASE DESCRIPTION/METHODS: A 51-year-old female with no significant past medical history presented with a 2 year history of iron deficiency anemia and PICA. She had experienced 3 weeks of RUQ pain, abdominal distension, and fatigue. Colonoscopy revealed a 15 cm infiltrative mass in the cecum. Pathology showed invasive poorly differentiated grade 3 small cell carcinoma of the colon (Figure 1). Immunostains + CAM, synaptophysin, MAP-2, and CDX2. CTscan showed diffuse liver metastasis. PET scan showed diffuse brain metastasis. Chemotherapy with cisplatin and etoposide was instituted. Her course was complicated by confusion, lethargy, pulmonary embolus, recurrent ascites, and sepsis. She passed away 8 months after diagnosis. DISCUSSION: The available literature consists mainly of series of case reports or small case series that provide guidance for optimal therapy to prolong survival. Prognosis is very poor and is secondary to the tumor's aggressive biology, the presence of metastatic disease at the time of diagnosis, and poor response to chemo/radiotherapy. Seventy percent of patients present with metastases at the time of diagnosis. The reported 6 months, 3 year and 5 year survival rates of 58%, 13%, and 6%, respectively, with a median survival of 10.4 months. There is no agreed standard treatment approach for colorectal SmCC at the present time. Combination of surgery, chemotherapy and radiotherapy is the standard at this time but overall prognosis is poor. It is of utmost importance to perform colonoscopic evaluation if patients have any alarm features such as iron deficiency anemia, unexplained abdominal pain, and altered bowel habits so that diagnosis can be made earlier.