Ultrastaging improves detection of metastases in sentinel lymph nodes of uterine cervix squamous cell carcinoma

The technique of sentinel lymph node (SLN) detection is increasingly being applied in patients with uterine cervix carcinoma. This study presents the pathologic findings of SLNs in 48 such patients. The institutional pathology files were searched for all patients with a diagnosis of cervical squamous cell carcinoma who had SLNs reported. Patient age, follow-up, tumor size, presence/absence of lymphatic invasion, number and status of SLNs and non-SLNs, location of SLNs, and size of metastases in SLNs were recorded. All SLNs were sectioned in 2-mm slices perpendicular to the long axis and submitted entirely for microscopic examination. For all SLNs negative on the initial hematoxylin and eosin (H&E) stained slides, an ultrastaging protocol was performed consisting of 5 sets of slides at 40-μm intervals (1 H&E slide+2 unstained slides), representing an additional 5 intervals. Lymph nodes negative by the additional H&E intervals had immunohistochemistry for cytokeratin performed on 1 unstained slide. Forty-eight patients ranging from 25 to 62 years of age had a total of 208 SLNs removed. Fifteen (31%) patients had positive SLNs with 1 to 5 positive SLNs per case. The metastasis size ranged from a single cell to 27 mm. Twelve patients had metastasis detected by routine processing in 23 SLNs, whereas ultrastaging detected metastases in 3 SLNs of 3 additional patients. In 2 patients with metastasis detected by ultrastaging, the metastasis was detected by wide H&E intervals (level 2 for 1 patient; level 3 for 1 patient); in 1 patient, the metastasis was detected only by immunohistochemistry and consisted of a single cell. Of the 15 patients with positive SLNs, 3 patients had a total of 6 positive non-SLNs. All of the patients with a positive SLN are currently living. Thirty-three (69%) patients had negative SLNs. Of these, 1 patient had a single positive non-SLN for a false negative rate of 6.25%. Negative SLN predicts negative non-SLN. For most patients with a positive SLN, the SLN will be the only metastasis detected; a minority of patients with a positive SLN may have a positive non-SLN.