Sentinel Lymph Nodes and Vulvovaginal Melanoma: Comparison of Sentinel Lymph Node Protocols
Elizabeth D Euscher, Anais Malpica. University of Texas MD Anderson Cancer Center, Houston, TX
Background: Sentinel lymph node (SLN) biopsy is recommended for staging of patients (pts) with clinically node negative melanoma at any site; however, no universal pathology protocol for processing SLNs exists. Most centers utilize a combination of additional H&E levels (lev) and immunohistochemistry (IHC), but the number of and optimal distance between levels remain subject to debate. This study presents a single institution experience with two different SLN protocols in cases of vulvovaginal melanoma (VVM).
Design: From 1995-2012 30 pts with VVM underwent SLN biopsy. Pt age, follow up, tumor size, tumor thickness, presence/absence of lymphovascular invasion, number/status of SLN and non SLN and size of SLN metastases were recorded. Ultrastaging (US) was performed on 26 pts with negative SLN on the initial H&E slide: H&E lev only, 3 pts; 1H&E lev (at 4-16µ) with IHC, 17 pts; superficial lev (at 4-16µ) plus 4 additional H&E lev (250µ) with IHC, 6 pts; not performed, 2 early pts. To determine whether wide interval (WI) H&E lev plus IHC was superior to one H&E lev plus IHC, 4 additional WI at 250µ were cut in all cases without WI. IHC with a PanMel stain was performed in cases lacking IHC.
Results: Pts' ages ranged from 17-85 yr (62, median) with 5-149 months follow up (29, median) available for 27 pts: alive, 11 pts; alive with disease, 2 pts; dead of disease, 13 pts; dead unknown cause, 1 pts. Tumors (.55 to 5.0 cm; median 1.6 cm) ranged from .43-12.0 mm (2.0 mm, median) thick. 110 SLN were identified (1-11 SLN/pt). 10 pts (30%) had 15 positive (+)SLN. Initial H&E section detected 6 (+)SLNs. US detected 9 (+)SLN; one (+)SLN was seen on the second WI H&E slide. Metastasis size ranged from 2 cells to 14.0 mm. In 4/15 (27%) SLN, metastases were detected by IHC only. 17 pts had 99 non SLN identified, and 2 pts had (+) nonSLN. There were no false negative SLN. Table 1 contains clinicopathologic features of the 30 pts.
|Feature||Positive SLN (n=10)||Negative SLN (n=20)|
|Median Age (yr)||56.5||65.5|
|Follow up||6/10 pts DOD||7/20 pts DOD|
|Tumor thickness (mean, mm)||3.25 ±3.35||3.17 ±3.17|
|Lymphovascular invasion present||5/10||10/20|