Tumor shrinkage associated with whole-mount histopathologic techniques in oral tongue carcinoma

Shrinkage artifact of tumor tissue from histologic processing has not been rigorously quantified, particularly where the entire tumor is represented in a whole-mount specimen. Fourteen patients underwent partial-glossectomy for oral tongue carcinoma (OTC). Specimens were embedded into agar, cut into 3 mm blocks and photographed (macroscopic image), prior to histopathologic processing. Histology slides were digitized. Contours were made of tumor on both image sets and area plotted against block position. Volume estimates were mathematically derived based on these plots. The tumors shrank in volume by 20.2% (p = 0.0006) on average; shrinkage by area ranged for all image pairs 0–48%. Tumor volume > median was significant in absolute shrinkage (p = 0.002) but not percent shrinkage (p = 0.42). Age, gender, and T stage were independent of shrinkage. This data shows whole-mount techniques produce shrinkage artifact in OTC that varies between tumors and blocks in the same tumor. In order to account for shrinkage, measurement must be performed case-by-case.