Heterotopic ossification in metastatic colorectal carcinoma: case report with morphoproteomic insights into the histogenesis.

A case of metastatic colorectal carcinoma with heterotopic ossification is described. Objective Morphoproteomic analysis was performed to help define the histogenesis of the heterotopic ossification in this context. Design Immunohistochemical stains for Gli2, α-SMA, SPARC (osteonectin), and nestin were performed and the expression level (chromogenic signal intensity) and subcellular compartmentalization of these protein analytes were assessed in the tumor cells vis-à-vis the companionate stromal cells and osteoblasts in a morphoproteomic application. Results This analysis revealed that the heterotopic ossification is more likely the result of pluripotent stromal cells that undergo differentiation to form osteoblasts rather than the tumor cells undergoing osseous metaplasia. Conclusion Morphoproteomics provides evidence that the histogenesis of heterotopic ossification in this case of metastatic colon cancer is from the stromal cells in the tumoral microenvironment.