Submucosal invasion in colorectal cancer

smHistopathology produces images which are basically two-dimensional sections across a three-dimensional object in a particular plane (and that plane is often fairly random). There is a long history of trying to reconstruct three-dimensional objects from histology images, I remember looking at a three-dimensional reconstruction of a bronchial mucus gland produced from polystyrene ceiling tiles by the late Prof. Bill Whimster – an early pioneer of these techniques. Advances in digital imaging and computing power have made three-dimensional reconstruction a more feasible proposition but so far it has rarely demonstrated anything that has relevance to diagnostic histopathology. In this month’s Histopathology Prof. Phil Quirke’s group at Leeds have produced results from three-dimensional reconstruction that could change our practice. The study used immunohistochemical staining of colon specimens to define the lymphovascular structures in the submucosa and they found that the density of lymphovascular vessels does not increase with increasing depth in the submucosa. This means that risk of metastases does not necessarily increase with deeper invasion (as embedded in some staging systems such Kikuchi’s) but it is more likely that total volume of submucosal invasion would be the best predictor of metastatic potential.