Immunohistochemical analysis of sentinel lymph nodes from patients with Merkel cell carcinoma

BACKGROUND. Immunohistochemical analysis of sentinel lymph nodes from patie nts with breast carcinoma and melanoma has been shown to increase the sensi tivity for detecting lymph node metastases. To the authors' knowledge, this technique has not been described in patients with Merkel cell carcinoma. METHODS. Lymphatic mapping and sentinel lymph node biopsy was performed on 26 patients with Merkel cell carcinoma between 1997 and 1999. All sentinel lymph nodes were analyzed with conventional hematoxylin and eosin (H&E) sta ining and then analyzed with immunohistochemical staining to evaluate wheth er this additional technique would increase the number of patients found to have lymph node metastasis. RESULTS. The median age of the patients in the current study was 67 years a nd the median tumor size at the time of presentation was 2 cm. Lymph node m etastases were identified in 5 of the 26 patients (19%). Three of these fiv e lymph node positive patients were identified with H&E staining. The remai ning two patients were identified only after immunohistochemical analysis. The median follow-up in this group of lymph node positive patients was 14 m onths, with 2 of the 5 lymph node positive patients developing a recurrence . The median follow-up in the 21 patients who were lymph node negative was 19 months, with only I patient having developed a recurrence at the time of last follow-up. CONCLUSIONS. Immunohistochemical analysis of sentinel lymph nodes from pati ents with Merkel cell carcinoma appears to increase the sensitivity of dete cting clinically occult lymph node metastases. (C) 2001 American Cancer Soc iety.