Spontaneous regression of an human papillomavirus-positive oropharyngeal squamous cell carcinoma

Background Spontaneous regression (SR) of cancer is an exceedingly rare phenomenon. While SR is well-documented for some cancers, very few reports exist in oropharyngeal squamous cell carcinomas (OPSCCs) and none in human papillomavirus (HPV)-positive OPSCCs. Methods A 67-year old man presented with a left-sided neck mass. Neck CT, PET, and biopsies showed a SCC in a left-sided lymph node without a primary lesion. Immunohistochemistry confirmed HPV16. Six weeks after biopsy, the patient underwent left selective tonsillectomy and neck dissection. Results Surgery revealed a left tonsillar SCC and no lymph nodes with tumor. Histology revealed homogenous fibrosis and intermixed immune cells indicative of tumor regression analogous to reports of immune-related pathologic responses. AE1/AE3 immunostain was also negative for tumor. All lymph nodes remained negative at 1 year follow-up. Conclusion We described a spontaneously regressed lymph node in a tonsillar HPV-positive SCC. The unique immune environment of HPV-positive OPSCCs, and unknown environmental or host factors, may have played a role in our patient's SR which requires future studies to elucidate.