Enhanced Pathologic Analysis for Pericolonic Tumor Deposits: Is It Worth It?

To the Editor Tumor deposits (TDs) are metastatic lesions commonly encountered in the routine histopathologic examination of advanced colorectal (CRC) specimens. In some cases, these lesions are associated with structures such as nerves, lymphatic vessels, venous vessels, and lymphatic aggregates, which can be found near the primary tumor or at some distance from it. In other cases, when no remnants of preexisting structures are identifiable, one could be puzzled by the interpretation of such lesions.1 In the previous TNM editions, the classification of TDs was based on a single morphologic criterion: the size ( 3 mm)2 and the shape (irregular vs smooth contour).3 However, the 3-mm rules were subsequently not confirmed4 and the shape showed poor reproducibility.5 For these reasons, the 2 classifications were abandoned.3,6 Instead of a morphologic feature indicating the likely nature of a TD, another approach is to try to assess the actual origin of the TD, which can be done with enhanced pathologic analysis (EPA). The article by Wunsch et al7 highlights the usefulness of assessing the nature of TDs with EPA. The authors step-sectioned the complete tumor regions of 7 cases of T3 CRC positive for peritumoral TDs in a series of 21 evaluated cases. TDs were defined as …