Actinomycosis of the neck: diagnosis by fine-needle aspiration biopsy.

A patient with actinomyces infection of the posterior neck was diagnosed by fine-needle aspiration biopsy. The lesion presented as a recurrent, firm, and indurated mass that was clinically diagnosed as adenitis and cellulitis and was thought to be a lymphoma 6 months after the onset of his illness. Smears and cell block sections of the aspirate showed characteristic colonies ("sulfur granules") of actinomyces. Subsequent regional lymph node biopsy revealed reactive lymphoid hyperplasia.