Figure 1:

Example of histologic sampling error in false-negative sentinel lymph node. A: Whole slide image of frozen section slide with total surface/lymph node area outlined in red (24.9 mm²), B: Whole slide image of permanent frozen section control slide after formalin fixation and paraffin embedding with total lymph node area outlined in green (51 mm²) and total surface area outlined in red (130 mm²), C: Permanent section of false-negative lymph with metastatic focus outlined in black (H&E, 40X), D: Permanent section of false-negative lymph node with metastatic focus not present in original FS slide (H&E, 100X)