Palatine Tonsilloliths and <i>Actinomyces</i>: A Multi-institutional Study of Adult Patients Undergoing Tonsillectomy.

Abstract

To better characterize associations between <i>Actinomyces</i> and tonsillolith versus nontonsillolith tonsillectomy specimens. Bi-institutional retrospective case-case study. University and county hospital. Adult patients with a clinical history of tonsilloliths who underwent tonsillectomy from January 2006 to December 2018 were included. Patients undergoing tonsillectomy for tonsillar hypertrophy and chronic tonsillitis were identified as comparative cases. Similarly, patients with ipsilateral oropharyngeal cancer (OPC) who underwent contralateral tonsillectomy of a normal-appearing tonsil for prophylaxis against a second primary cancer were also included as comparative cases. The study population comprised 134 patients who underwent tonsillectomy: 62 tonsillolith and 72 nontonsillolith (tonsillar hypertrophy, n = 30; chronic tonsillitis, n = 30; normal-appearing contralateral tonsil in patients with ipsilateral OPC, n = 12). <i>Actinomyces</i> was reported in 11% of the patients with tonsilloliths on initial pathology reports but in 95% after re-evaluation (n = 54 of 57). <i>Actinomyces</i> prevalence was significantly higher in patients with tonsilloliths as compared with patients with recurrent tonsillitis (73%, n = 22 of 30, <i>P</i> < .001) and normal-appearing contralateral tonsils in patients with ipsilateral OPC (58%, n = 7 of 12, <i>P</i> < .001). <i>Actinomyces</i> prevalence was not significantly different between patients with tonsilloliths and tonsillar hypertrophy (83%, n = 25 of 30, <i>P</i> = .11). The prevalence of <i>Actinomyces</i> in tonsillolith tonsil specimens is high; however, <i>Actinomyces</i> routinely colonizes nontonsillolith tonsil specimens. Therefore, <i>Actinomyces</i> is unlikely to be the primary driver of tonsillolith pathogenesis, and <i>Actinomyces-</i>targeted treatment of tonsilloliths may not be effective. Treatment strategies addressing tonsilloliths should be further investigated.