The need for vigilance in the pathologic evaluation of sentinel lymph nodes: a report of two illustrative cases.

The advent of sentinel lymph node (SLN) biopsy for breast cancer has had a considerable impact on clinical oncology. The SLN procedure has been widely adopted, but major clinical issues remain unresolved pending the outcome of randomized trials. Pathologic handling of SLNs is less controversial; however, significant pitfalls in their handling have been reported. Herein we report two additional uncommon situations that demonstrate the need for the utmost vigilance in both the macroscopic examination (i.e., trimming of "positive" nodal tissue) and microscopic examination (i.e., presence of nevus cell aggregates mimicking metastatic carcinoma) of SLN specimens.