Actinomycosis mimicking carcinoma of the maxillary sinus.

Human actinomycosis may pose a diagnostic problem at times and is often mistaken for a neoplasm. A thirty-five year old male was clinically diagnosed as a case of carcinoma of the right maxillary sinus on the basis of history, clinical presentation and radiologic findings. Tissue biopsy was negative for malignancy on three consecutive occasions. Microscopic examination showed bits of granulation tissue and fragments of filamentous structures. On microbiological examination, Actinomyces israelii was isolated and fungus culture was negative. Long term Penicillin treatment caused disappearance of all signs and symptoms. The report highlights the importance of bearing in mind the fact that certain rare, chronic, suppurative granulomatous infections, like actinomycosis, may mimic malignancy.