Incidental histopathological diagnosis of tonsilar actinomycosis: A report of four cases.

Actinomycosis of the tonsils is uncommon even though the causative organisms are normal commensal of the oropharyngeal tract that may colonise the tonsillar crypts with resultant infection in apparently healthy individuals. Diagnosis is often incidental in tonsillectomy specimens sent to the pathology laboratory for varied diseases. This is a 10-year study of tonsillectomy specimens diagnosed with actinomycosis. Specimens were formalin-fixed and paraffin processed and stained with haematoxylin and eosin, gromott methenamine silver and periodic acid-Schiff. Four cases of tonsillar actinomycosis were diagnosed from a total of 772 tonsillectomy specimens. Histologically, characteristic oeosinophilic granules with peripheral radial protuberances surrounded by microabscesses were seen. Tonsillar actinomycosis is often an incidental diagnosis; however, a high index of suspicion should be entertained in patients with recurrent tonsillitis and/or tonsillar hypertrophy of unknown cause.