An unusual case of isolated brain metastasis with impending brain herniation from sigmoid colon cancer: case report and review of literature.

Colorectal carcinoma with a finding of isolated brain metastasis is rare. Furthermore, neurologic symptoms secondary to oligometastasis to the brain are very rare initial presentations for colorectal cancer. Hence, it is uncommon to do brain imaging in the initial staging of colon carcinoma. We present an unusual case of a patient who initially presented with a headache. Laboratory tests revealed mild anemia. Brain imaging revealed a mass in the parietal lobe; hence, neurosurgery was performed with resection of the mass. Histopathology showed it's colonic in origin. Colonoscopy revealed adenocarcinoma in the sigmoid colon and a staging computed tomography scan showed no distant metastases. This case report highlights the unusual presentation of an isolated brain metastasis secondary to primary colon carcinoma. Any patient with a primary colon tumor who complains of neurologic symptoms should be considered for brain evaluation to minimize the risk of overlooking such important finding.