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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, OBJECTIVE, METHODS, RESULTS. Meshes: Aged, Aged, 80 and over, Carcinoma, Merkel Cell, Culture Techniques, Female, Humans, Immunohistochemistry, Keratins, Lymph Nodes, Lymphatic Metastasis, Male, Middle Aged, Neoplasm Invasiveness, Registries, Sensitivity and Specificity, Sentinel Lymph Node Biopsy, Skin Neoplasms.
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Does immunostaining for cytokeratin 20 improve detection of micrometastatic Merkel cell carcinoma in sentinel lymph nodes? Context: Sentinel lymph node biopsy (SLNBx) can identify Merkel cell carcinoma (MCC) micrometastasis. We attempted to examine the effectiveness of immunostaining and identify antibodies most appropriate for evaluation of SLNBxs for MCC. Histopathologic material from 10 patients with MCC who had SLNBx was reviewed. Twenty-three SLNBxs from 10 patients appeared tumor-free in routine hematoxylin-eosin (H&E)-stained sections. However, tumor cells were detected in immunostained sections from 5 (22%) of 23 SLNBxs in 4 (40%) of 10 patients. Immunostains with pancytokeratin (panCK), cytokeratin-20 (CK-20), neurofilament protein, and chromogranin A were used for all primary and SLNBx specimens. All 5 (100%) micrometastatic foci stained strongly for CK-20 and panCK. Background normal lymph node tissue also stained for panCK but not for CK-20.
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Examination of H&E sections alone is insufficient for excluding micrometastatic MCC in sentinel lymph nodes. We observed the greatest sensitivity and specificity with anti-CK-20 antibody in identifying micrometastatic MCC in sentinel lymph nodes. Final Decision: yes