Unusual Osseous Metastases from Rectal Adenocarcinoma: A Case Report and Review of the Literature

Rectal adenocarcinoma typically metastasizes to the liver. When osseous spread occurs, it is most commonly detected in the vertebrae and pelvis. Distal osseous spread is unusual and may be the first presentation of the carcinoma. We present a review of the current literature on unusual osseous rectal adenocarcinoma metastases and highlight a case of a scapular lesion as the first presentation of rectal carcinoma from our institution. A Pubmed search using keywords 'rectal carcinoma metastases,' 'colorectal cancer metastases' and 'skeletal metastases' was performed. Twenty-four cases were identified (54 % male, mean age at diagnosis 61 +/- 16 years). The most common site was the mandible, followed by the foot. In four cases, the metastasis was the first presentation of the carcinoma. Mean time from resection of the primary tumour to osseous metastases diagnosis of skeletal metastases was 26 +/- 17 (SD) months. Mean time from diagnosis of skeletal metastases to death was 3.2 (+/- 2.8) months. Rectal adenocarcinoma osseous metastases located distal to the pelvis and/or vertebrae are rare and associated with a poor prognosis. Unusual bony lesions should raise an index of suspicion for distal carcinoma, including rectal carcinoma.