Second Primary Tumors in Patients Presenting With Unilateral HPV-Associated Tonsillar Squamous Cell Carcinoma

Investigations for Suspected Head and Neck Squamous Cell Carcinoma of Unknown Primary (HNSCCUP): A National Cohort Study

OBJECTIVES

Head and neck squamous cell carcinoma from unknown primary (HNSCCUP) is a rare and challenging condition. This study aimed to investigate the diagnostic pathways of suspected HNSCCUP patients in the United Kingdom.

METHODS

A retrospective observational cohort study was conducted, over 5 years from January 2015, in UK Head and Neck centres of consecutive adults undergoing 18F-Fluorodeoxyglucose-PET-CT (PET-CT) within 3 months of diagnosis with metastatic cervical squamous cell carcinoma. Patients with no primary site on examination and no previous head and neck cancer were eligible.

RESULTS

Data for 965 patients were received from 57 centres; 68.5% were HPV-related disease. Three investigation cycles were observed: ultrasound with biopsy, cross-sectional imaging (MRI and/or CT) and PET-CT, at median times of 17, 29.5 and 46 days from referral. No primary was identified on PET-CT in 49.8% (n = 478/960). Diagnostic tonsillectomy was performed in 58.2% (n = 278/478) and tongue base mucosectomy (TBM) in 21.7% (n = 104/479). Ipsilateral tonsillectomy carried the highest diagnostic yield (18.7%, n = 52/278), followed by TBM (15.4%, n = 16/104). Contralateral tonsillectomy, performed in 49.0% (n = 234/478), carried the lowest yield (0.9%, n = 2/234). PET-CT with concurrent MRI was associated with higher primary site detection than PET-CT with concurrent CT (p = 0.003). A minority of patients undergoing treatment with curative intent received first-definitive-treatment within 62 days of referral (15.2%, n = 77/505, median 92 days, IQR: 71-117).

CONCLUSIONS

Most patients experienced a protracted diagnostic pathway and waited over 3 months for definitive treatment. Earlier PET-CT with concurrent MRI may expedite diagnosis. TBM appears more productive than contralateral tonsillectomy for primary site detection.

Prevalence of synchronous bilateral/contralateral tonsil carcinoma: A systematic review and meta-analysis

The purpose of this systematic review and meta-analysis was to identify the prevalence of synchronous contralateral tonsil carcinoma (SCTC) amongst patients with tonsil carcinoma or head and neck squamous cell carcinoma of unknown primary (HNSCCUP). Thirteen retrospective studies, comprising 2623 patients, were analysed, revealing an overall pooled SCTC prevalence of 4%, rising to 10% in HNSCCUP cases. HPV/p16 positivity was associated with SCTC prevalence of 3%, while HPV/p16 negativity was greater at 8%. Clinical or imaging evaluations often missed SCTC preoperatively, emphasising the importance of contralateral tonsillectomy. Morbidity varied among patients undergoing contralateral tonsillectomy. The prevalence of SCTC is significant in cases of HNSCCUP and tonsil malignancy, emphasising the importance of informed discussions regarding contralateral tonsillectomy. Tailored approaches considering individual patient and tumour characteristics are crucial, with contralateral tonsillectomy generally warranted in HNSCCUP. Further research, including prospective studies with standardised protocols, is needed to improve the understanding and management of SCTC, specifically the clinical significance of occult SCTC.

Synchronous tonsillar tumors with differing histopathology: A case report and review of the literature

Background

Tonsillar squamous cell carcinoma (TSCC) due to human papillomavirus (HPV) infection has seen a dramatic increase in recent years. Bilateral tonsillar squamous cell carcinoma (biTSCC) has a much lower incidence than unilateral TSCC and three main hypotheses of biTSCC pathogenesis prevail: field carcinogenesis, single‐clone, and multiple HPV infections.

Case

A 49‐year‐old Male with a remote history of chewing tobacco presented with symptoms of spitting up tissue and occasional hemoptysis. Physical exam showed a sole left tonsillar mass which was confirmed to be TSCC on biopsy. The patient's computed tomographic (CT) scan was consistent with this finding; however, positron emission tomography (PET) scan indicated a second tumor in the contralateral right tonsil. Surgical resection of both masses and selective neck dissection was performed, and the specimens were sent for further pathological analysis. No complications of surgery were noted and the final diagnosis of synchronous biTSCC was made. The tumors were a T2N0M0 left poorly differentiated TSCC (p16+, EGFR+, bcl2+) with basaloid features, and a T1N0M0 right well to moderately differentiated TSCC (p16+, EGFR+, bcl2−).

Conclusion

Our present case was notable for differing tumor pathology and karyotype analysis between the right and left masses, directly supporting the multiple HPV infections hypothesis of biTSCC pathogenesis. Further genetic characterization of tonsillar tumors is needed to better characterize TSCC and best guide medical/surgical therapy.