Sentinel Nodal Metastasis Detection in Endometrial Carcinoma With Microcystic, Elongated, and Fragmented (MELF) Pattern by Cytokeratin Immunostaining

Abstract

Objectives The microcystic, elongated, and fragmented (MELF) pattern of myoinvasion in endometrial carcinoma (EC) is associated with an increased risk of lymph node metastasis. Our aim is to assess the role of cytokeratin immunohistochemical (IHC) stains in detecting sentinel nodal metastasis in MELF pattern tumors. Methods We recovered 19 MELF pattern EC hysterectomies with lymphadenectomy from our files. Negative nodes were subjected to cytokeratin AE1/AE3 IHC. Ten additional cases with sentinel lymph node (SLN) biopsies primarily assessed by IHC were also analyzed. Results Of the 19 cases of EC, 6 had positive lymph nodes based on H&E-stained sections at the time of their initial diagnosis. With the addition of IHC stains, 8 previously negative cases were found to have node metastases, and 3 of these were SLNs. Among the 10 cases primarily assessed by IHC, 5 had malignant cells in their SLNs. Conclusions Cytokeratin IHC staining detected malignant cells in 9 of 16 cases with SLNs in our sample of women with MELF pattern of myoinvasion. Immunohistochemical stains should be routinely performed on SLNs from all MELF-positive cases to detect occult lymph node metastases and isolated tumor cells.

Cytokeratin Expression Pattern in Human Endometrial Carcinomas and Lymph Nodes Micrometastasis: a Mini-review

“…Often subtle nodal metastases occurring in MELF-type ECs may also be precisely recognized with CK19 immunostaining [80,82]. Recently, Rabe et al [83] suggested the routine CKs staining on sentinel lymph nodes in MELF-pattern ECs to detect metastases and isolated tumor cells. Similarly, another study demonstrated that staining with CK8 and CK18 may be useful in detecting LVSI, emphasizing that higher stages of ECs had statistically higher LVSI (p ≤ 0.005) [66].…”

Microcystic Elongated and Fragmented Pattern Invasion in Endometrial Cancer: Possible Prognostic Value to Precise and Individualized Therapeutic Strategies

“…Moreover, Tahara et al 3 reported a strong expression of programed death-ligand 1 (PD-L1) in the invasive front of the MELF pattern and concluded that programed cell death protein 1/PD-L1 immunotherapy demonstrated significant therapeutic effect on the management of patients with endometrial cancer and grade 1 MELF. Furthermore, Rabe et al 4 claimed that cytokeratin IHC staining could detect malignant cells in the sentinel lymph nodes of patients with endometrial cancer and MELF.…”