Asymptomatic isolated coccygeal metastasis in low rectal carcinoma.

As well as being relatively rare, osseous metastases from colorectal cancer are frequently asymptomatic and represent a late manifestation of disease. We report a case of an unidentified, asymptomatic coccygeal metastasis discovered on histological processing of the resection specimen from a patient with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy followed by radical abdomino-perineal resection with coccygectomy. The anatomical explanation for this finding may involve passage of tumour cells via the vertebral venous plexus.