Small cell carcinoma of the large intestine presenting as central nervous systems signs and symptoms. Two case reports with literature review.

Extrapulmonary small cell carcinoma is rare. Small cell carcinoma of the colorectum has been reported in 73 patients. Patients with colorectal small cell carcinoma present with signs and symptoms related to the primary site. Usually patients present with advanced stage. Rarely do patients with colorectal small cell carcinoma present with signs and symptoms related to the central nervous system (CNS). We report two patients who presented with CNS signs. The two patients underwent craniotomy for definitive diagnosis and resection in one patient. In both cases, pathology was consistent with pure small cell carcinoma. Post-operatively, a search for a primary revealed the rectum and the hepatic flexure of the colon to be the sites. Patients were started on combination chemotherapy. One patient achieved a complete remission and the second is currently receiving chemotherapy with a partial response. This is the first report of colorectal small cell carcinoma presenting as CNS lesion(s).