Occult tonsillar carcinoma in the unknown primary

Objectives: Evaluate effectiveness of routine tonsillectomy in the assessment of patients with squamous cell carcinoma of the neck of unknown primary, and evaluate outcomes of this group compared with patients without a primary identified initially. Study Design: A retrospective review of the medical records of 37 patients presenting with an unknown primary tumor over a 10-year period. Methods: Charts were reviewed for age and sex of patients, methods of evaluation and diagnosis, sites of tissues obtained on biopsy, N stage of disease, and presence of extracapsular spread. Recurrence and survival data were collected over a mean follow-up period of 34 months. Results: All primary lesions discovered through pathologic evaluation arose from the tonsil (9/9), and all were detected in patients undergoing tonsillectomy in conjunction with direct laryngoscopy. None of the patients (0/9) with occult tonsillar carcinoma have had recurrence, in contrast to 60% (15/25) of remaining patients. Patients with tonsillar primary lesions demonstrated less extracapsular spread of disease (25%) than patients without tonsillar primaries (67%), despite similar N staging within the two groups. Conclusions: Occult tonsillar carcinoma accounts for the unknown primary more frequently than was previously recognized. Bilateral tonsillectomy is recommended to increase the detection yield and to capture the rare case of bilateral disease. A lower incidence of extracapsular spread and reduced recurrence rates in patients with unknown primary tumors presenting as occult tonsillar carcinoma may contribute to the improved prognosis observed in this group.