Sentinel lymph node biopsy in patients with extramammary Paget's disease.

Background. Patients with invasive extramammary Paget's disease appear to have a risk of regional lymph node metastasis. Despite the poor prognosis for patients with lymph node metastasis, management of extramammary Paget's disease without clinical evidence of involved nodes is controversial. Objective. To evaluate the usefulness of sentinel lymph node biopsy, patients with extramammary Paget's disease underwent sentinel lymph node biopsy using preoperative lymphoscintigraphy and intraoperative patent blue dye injection with a handheld gamma-detecting probe. Methods. Thirteen patients with primary genital extramammary Paget's disease were included in the study. Sentinel nodes identified were excised and examined by hematoxylin and eosin staining. All sentinel lymph nodes were also subjected to immunohistochemical staining for carcinoembryonic antigen, MUC1, cytokeratin 7, and gross cystic disease fluid protein-15. Results. A total of 23 nodes were removed successfully. Tumor cells were detected in 4 nodes from four patients by hematoxylin and eosin staining. No additional lymph nodes were positive by immunohistochemistry. Three of the four sentinel-node-positive patients developed distant metastases. All nine patients without node involvement were free from disease during the follow-up period. Conclusion. Sentinel lymph node biopsy was safe and feasible method and may have an important role in the management of extramammary Paget's disease with clinically N0 status. To establish the optimal management of inguinal lymph nodes in extramammary Paget's disease, additional studies in large number of patients are needed.