軟口蓋穿孔を契機に診断された咽頭放線菌症の1例

抄録

Soft palate perforation in an adult is a challenge for differential diagnosis. The differential diagnosis includes a wide variety of diseases, such as granulomatosis with polyangiitis (GPA), malignancy such as NK/T cell malignant lymphoma, tuberculosis, and syphilis. A rare manifestation of actinomycosis, a perforation in the left soft palate, is presented. Typically, actinomycosis presents as a slowly progressive, painless, indurated mass, evolving into multiple abscesses with draining sinus tracts on the skin surface or oral mucosa. Therefore, it often misdiagnosed as malignancy or tuberculosis due to their similar appearances. The case of a 75-year-old man with long-term tobacco abuse and recurrent tonsillitis who presented with soft palate perforation is described. Imaging findings were noncontributory to the diagnosis. Cultures from the oral smear were unremarkable and did not reveal actinomycosis, probably due to its anaerobic nature. Histopathological examination of actinomycotic granules was useful in the diagnosis. First, surgery was performed, similar to tonsillectomy, to excise a recalcitrant fibrotic lesion. The patient received intravenous benzylpenicillin potassium (PCG, 400 MU/day) for 6 weeks, followed by oral therapy with ampicillin sodium (ABPC, 1000 mg/day) for 4 months. During the 4-month follow-up period, no recurrence was observed. The traditional prolonged, high-dose penicillin treatment can likely be shortened and the dose reduced if sufficient surgical resection of the infected tissues is performed in the absence of bone involvement.

The present case highlights the importance of actinomycosis in the differential diagnosis of soft palate perforation.