Heterotopic ossification in rectal cancer: Rare finding with a novel proposed mechanism.

The rare finding of heterotopic ossification in a case of primary rectal adenocarcinoma is described along with a review of the literature. Immunohistochemistry for a bone morphogenic protein (BMP-2) and fibroblast growth factor (FGF-2), both of which induce and stimulate bone formation, was performed and revealed overexpression of BMP-2 by the tumor cells, elucidating a possible mechanism which up to now had been based merely on speculation.