Neck Node Squamous Cell Metastasis from Unknown Primary and Mutagen Sensitivity: A Case Series

Area of Science:

• Oncology
• Pathology

Background:

• Cancer of unknown primary (CUP) frequently presents as neck node metastases, predominantly squamous cell carcinomas (SCCs).
• Many of these SCCs are human papillomavirus (HPV)-related and may originate from Waldeyer's ring, often exhibiting cystic morphology.

Observation:

• This study reports four cases of neck node SCC metastases from CUP in patients under 50 years old.
• All four patients had undergone pretreatment mutagen sensitivity (MS) assay and exhibited elevated MS levels (>1.0 chromatid break/cell).

Findings:

• One male patient died within 3 years, while three female patients survived over 15 years post-treatment.
• The survivors had HPV-positive (two) or cystic (one) SCC. Two survivors developed metachronous primary cancers at distant sites.
• Elevated MS in HPV-positive or cystic head and neck SCC (HNSCC) from CUP appears to correlate with a favorable prognosis.

Implications:

• Elevated MS may serve as a predictive biomarker for good outcomes in specific subtypes of CUP neck node metastases.
• The development of metachronous cancers of different histologic types in survivors warrants further investigation beyond the field cancerization hypothesis.
• Further research is needed to elucidate the clinical significance of elevated MS in CUP neck node SCC metastasis.