Fluid biopsy for circulating tumor cells in an occult ovarian cancer patient exhibiting bilateral supraclavicular lymph node metastases: A case report

Metastases to the supraclavicular region usually originate from the head and neck or from infraclavicular tumors. Ovarian primaries of supraclavicular metastases are extremely rare. The present study reports the case of a 60-year-old patient with a bilateral supraclavicular mass that was diagnosed as a poorly-differentiated squamous cell carcinoma of unknown primary, following a fine-needle aspiration biopsy (FNAB) and comprehensive clinical investigation. The analysis of a peripheral blood sample using the CellSearch system revealed the presence of circulating tumor cells (CTCs) that were positive for epithelial cell adhesion molecule (EpCAM) and cytokeratin (CK) expression. Since EpCAM is usually expressed in adenocarcinoma, an excisional biopsy of the right supraclavicular lymph node was performed. The patient was diagnosed with occult ovarian low-grade serous carcinoma by immunohistochemistry. To the best of our knowledge, this is the first report to demonstrate that CTCs may be detected in the peripheral blood of a patient with cancer of unknown primary (CUP) by using the CellSearch system. A literature review was performed to analyze the diagnostic procedures of CUP metastatic to the cervical lymph nodes and the clinical features of CTCs.