Primary Extrapulmonary Small Cell Carcinoma of the Appendix: A Case Report

ABSTRACT

Primary extrapulmonary small cell carcinoma (EPSCC) of the appendix is an extremely rare entity, and there has been only one previous report on this in the English medical literature. We report here on the first Korean case of EPSCC of the appendix in a 55-year-old woman. The patient had no history of an identified pulmonary tumor, and she presented with constipation and lower abdominal pain. The patient underwent right hemicolectomy with regional lymph node dissection and bilateral salphigo-oophorectomy. The histology of the entire appendiceal tumor revealed pure EPSCC with diffuse immunoreactivity for pancytokeratin, cytokeratin 7, cytokeratin 20, CD56, thyroid transcription factor 1, c-kit and carcinoembryonic antigen, and there was focal weak immunoreactivity for chromogranin A and synaptophysin. After the second cycle of chemotherapy, the condition of the patient gradually deteriorated due to cancer peritonei and the patient died 7 months later. EPSCC of the appendix is a distinctive clinicopathological entity that displays highly aggressive behavior and an unfavorable outcome.