Cervicofacial actinomycosis: CT and MR imaging findings in seven patients.

BACKGROUND AND PURPOSE Cervicofacial actinomycosis is uncommon, but without proper treatment it causes extensive tissue destruction. Early diagnosis is critical but usually difficult with cultures or imaging. Our aim was to identify characteristic imaging features that facilitated diagnosis in seven patients with cervicofacial actinomycosis. METHODS We retrospectively reviewed the CT and MR findings in seven patients with pathologically proved actinomycosis. Histologic diagnosis was made by means of surgical excision or biopsy in seven patients. Culturing was performed in two patients. Enhanced CT scans (n=7) and MR images (n=2) were evaluated for the location, margin, infiltrative nature, enhancement pattern, and presence of lymphadenopathy. RESULTS CT and MR images showed either a well-defined (n=2) or ill-defined (n=5) mass. Involved areas included the nasal cavity (n=2), buccal space (n=1), pyriform sinus (n=1), aryepiglottic fold (n=1), oro- and hypopharynx (n=1) and tongue (n=1). Imaging confirmed the infiltrative nature, showing the tendency of the lesion to invade across tissue planes and boundaries (n=6). Moderate homogeneous contrast enhancement was seen on CT scans in six patients with several small low-attenuating foci (n=2). T1- and T2-weighted MR images showed intermediate signal intensity with moderate contrast enhancement (n=2). Reactive lymphadenopathy was associated in three patients. CONCLUSION Although cervicofacial actinomycosis occurs infrequently, it should be included in the differential diagnosis when images show a soft-tissue mass with inflammatory changes and an infiltrative nature in the cervicofacial area.