Detection of metastatic vulvar and cervical squamous carcinoma in regional lymph nodes by use of a polyclonal keratin antibody.

A polyclonal keratin antibody (pK), a marker for epithelial cells, was used to evaluate lymph nodes (LNs) from patients with invasive squamous carcinomas of the cervix (CxCa) or vulva (VCa) to determine whether this technique could increase the detection of metastases (mets) over that obtained by light microscopy using a routine hematoxylin and eosin (H&E)-stained slide. The LN status of 15 cases of stage 1B CxCa and 14 cases of VCa was determined using a routine H&E slide. Subsequently, all LNs were resectioned and examined using a pK immunoperoxidase stain. In 329 lymph nodes from 14 cases of CxCa and 9 cases of VCa originally classified as LN-negative, only a single met was detected by the pK technique. In five cases of VCa and one case of CxCa (121 LNs), with LN mets or LN tumor emboli on the original H&E, three additional microscopic foci of mets were detected by pK. Of the four foci of mets discovered by pK, one was visible in retrospect on the original H&E section, and all four were easily identified on examination of a serial H&E section adjacent to the pK section. These results suggest that pK stains are unlikely to significantly increase our sensitivity in detecting mets in CxCa and VCa, beyond merely further sectioning and H&E staining of nodes.