Visualization of Scattered Tumor Regression Following Neoadjuvant Chemoimmunotherapy With a Novel Intraoperative PET/CT Scanner.

Radevic, Andreja; Austerlitz, Joaquin; McAdoo, Ashtyn; Golliday, Kyrionna; Takahashi, Takeshi; Mehrad, Mitra; Rosenberg, Adam J; Murphy, Barbara A et al. · Head Neck · 2026

case_report · Level V

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Abstract

Neoadjuvant chemoimmunotherapy is being explored in locally advanced head and neck squamous cell carcinoma (HNSCC), yet the spatial patterns of pathologic response and clinical implications remain poorly characterized. A 79-year-old female with recurrent left oral tongue SCC (PD-L122C3 Combined Positive Score 90) who underwent prior resection and free flap reconstruction received neoadjuvant pembrolizumab, paclitaxel, and carboplatin followed by definitive surgical resection with intraoperative positron emission tomography/computed tomography (PET/CT) imaging. Final histopathology revealed two discrete foci of residual poorly differentiated SCC, measuring 1.8 and 0.5 cm, separated by an 8 mm intervening bridge of inflammation without viable tumor. Intraoperative PET/CT with 3D specimen mapping confirmed the spatial relationship between residual foci and intervening treatment effect. Pathologic response to neoadjuvant chemoimmunotherapy in HNSCC can manifest as a multifocal regression pattern. Intraoperative real-time approaches to assessing treatment response warrant further investigation. ClinicalTrials.gov identifier: NCT06915454.