Acrometastasis as the Initial Presentation of a KRAS-Positive Colon Cancer

The propensity of colon cancer to metastasize to bones is very low compared to prostate, breast or lung cancer. The reason for this is not yet understood, although an explanation for the osteotropism of certain primaries has been offered by the ‘seed and soil’ concept, suggesting that the bone microenvironment provides a favorable ‘soil’ for metastasis and proliferation of some tumor cells (‘seeds’) [1]. Here, we report an unusual case of colon cancer with metastasis to the finger at initial presentation, and exophytic sclerotic lesions to other bones. The incidence of metastases to fingers/toes (acrometastases) is reported to be only 0.1%, even after including involvement of primary sites other than the colon. The etiology and characteristics of acrometastases are reviewed in this case report.