Histopathologic review of negative sentinel lymph node biopsies in thin melanomas: an argument for the routine use of immunohistochemistry

Sentinel lymph node biopsy (SLNB) is performed for some thin melanomas in the presence of concerning histopathological features. There are no defined standards for how sentinel nodes should be processed to detect microscopic metastases. We compared our method of serially sectioning nodes at 2–3 mm intervals and performing one hematoxylin and eosin (HE 3/49 (6.1%) nodes had benign nodal rests. All other nodes (45/49, 91.8%) were negative by H&E and IHC for metastatic disease. This study supports previous work suggesting the value of IHC in detecting micrometastases in melanoma sentinel nodes. Especially for thin melanomas where metastases are uncommon, but where detection of the metastasis upstages considerably from stage IA to IIIA, evaluation of nodes may be enhanced by combining breadloafing at 2–3 mm intervals with multiple H&E sections and IHC analysis.