Role of Sentinel Lymph Node Biopsy in the Staging of Synovial, Epithelioid, and Clear Cell Sarcomas

Soft tissue sarcomas generally have a a parts per thousand currency sign5% risk of lymph node metastasis, but synovial, epithelioid, and clear cell subtypes reportedly have a much higher risk. The utility of sentinel lymph node biopsy (SLNB) for patients with these sarcoma subtypes is unknown. 29 patients with nonmetastatic synovial, epithelioid, and clear cell sarcomas who underwent SLNB were examined. Median age was 35 years (range 11-73 years), and 69% were male. Tumors were located in the lower extremity in 17 patients and the upper extremity in 12. The histological subtypes were synovial sarcoma in 16 patients, epithelioid sarcoma in 10, and clear cell sarcoma in 3. All patients had a staging chest computed tomography (CT) scan, none of which were suspicious, and 20 patients had staging positron emission tomography (PET) scans (16 negative, 3 indeterminate, and 1 suspicious). All patients had resection of their primary tumor. At least one sentinel node was found in 28 patients (97%), and the median number of sentinel nodes identified was 2 (range 1-4). One patient had a positive sentinel node on routine hematoxylin and eosin (H&E) staining and developed lung metastases. Two patients had positive sentinel nodes following immunohistochemical staining, and both remain disease free despite not undergoing completion lymphadenectomy. One patient developed a lymph node metastasis after a negative SLNB. For patients with these sarcoma subtypes without radiological evidence of nodal or distant metastases, the incidence of occult lymph node metastasis is relatively low. Determining utility of SLNB may require a multicenter trial.