Para-Aortic Lymph Node Metastasis Detected by Sentinel Lymph Node Biopsy in Cervical Cancer Initially Presumed to be Stage IA2: A Case Report.

Sentinel node navigation surgery (SNNS) minimizes unnecessary lymphadenectomy and its associated complications while enhancing detection of lymph node micrometastases through ultrastaging. A 34-year-old nulligravid woman with a history of CIN2 was diagnosed with squamous cell carcinoma (4.5 mm width, 4 mm depth) with lymphovascular invasion after conization. Clinical stage was T1a2 (FIGO 2018). Modified-radical trachelectomy with SNNS was planned for fertility preservation. SPECT-CT identified bilateral obturator and left lower para-aortic sentinel nodes. Intraoperative frozen sections revealed a 1.1 mm micrometastasis in the left obturator node and a 2.5 mm macrometastasis in the left para-aortic node. The procedure was converted to modified-radical hysterectomy with bilateral adnexectomy and pelvic lymphadenectomy, followed by concurrent chemoradiotherapy including the para-aortic field. The patient remains disease-free at 10 months. Without SNNS, the para-aortic metastasis would have been undetected, resulting in inadequate radiation coverage. SNNS fundamentally changes therapeutic approaches by enabling accurate disease extent identification and individualized treatment.