Pathology of sentinel lymph nodes: historical perspective and current applications in gynecologic cancer

Abstract

Efforts to reduce surgical morbidity related to en bloc lymph node removal associated with cancer surgery led to the development of targeted lymph node sampling to identify the lymph node(s) most likely to harbor a metastasis. Through identification of one or only a few lymph nodes at highest risk, the overall number of lymph nodes removed could be markedly reduced. Submission of fewer lymph nodes affords more detailed pathologic examination than would otherwise be practical with a standard lymph node dissection. Such enhanced pathologic examination techniques (ie, ultra-staging) have contributed to increased detection of lymph node metastases, primarily by detection of low volume metastatic disease. Based on the success of sentinel lymph node mapping and ultra-staging in breast cancer and melanoma, such techniques are increasingly used for other organ systems including the gynecologic tract. This review addresses the historical aspects of sentinel lymph node evaluation and reviews current ultra-staging protocols as well as the implications associated with increased detection of low volume metastases.

Ability of dynamic contrast-enhanced magnetic resonance imaging to determine axillary sentinel lymph node status in patients with breast cancer

“…In the past, the clinical signi cance of lymph node metastases smaller than 2 mm was overlooked owing to the lower detection rate of pathology diagnosis. Recent advances in pathology have helped to improve the segregation of minimal lymph metastases [21]. The clinical signi cance of small-volume metastases of breast cancer in SLNs is now attracting attention, and there is published evidence to suggest that the SLNs in patients with breast cancer may determine the therapeutic strategy and the prognosis [22][23][24].…”

Value of sentinel node ultrastaging and pathologic techniques in tumoral detection

“…Based on the other neoplasms, adequate pathologic evaluation of sentinel lymph nodes is the utmost component of the diagnostic algorithms through additional hematoxylin and eosin (H&E) levels and immunohistochemical stains with variable protocols regarding the number of sections or levels, and the immunohistochemical markers [11,12]. However, for gynecologic oncology sentinel lymph node evaluation, the application of standards from other tumors is not necessarily a valid method because of differences with respect to lymph node metastasis risk, diverse tumor biology, and treatment approaches for positive lymph node disease [13]. Sentinel lymph node techniques in gynecologic cancer were first explored in vulvar carcinoma and after that, have been applied to cervical, endometrial, and lastly ovarian carcinoma [3,14–27,28 ▪ ].…”

Plug-and-Play Lymph Node-on-Chip: Secondary Tumor Modeling by the Combination of Cell Spheroid, Collagen Sponge and T-Cells

“…( c ) Secondary tumor due to metastasis in the sentinel lymph node (keratin stain). Reprinted with permission from Elizabeth Euscher (2020) [ 38 ]. ( d ) Photo of chip installed in the Operetta CLM system.…”