Suppurative granulomatous lymphadenitis caused by corynebacterium ovis (pseudotuberculosis)

A 30-year-old previously healthy man developed cervical adenopathy associated with mild constitutional symptoms. Corynebacterium ovis was isolated in pure culture from lymph node tissue on two separate occasions, and small gram positive organisms were identified in both lymph nodes with tissue gram stain. Histopathologically, the nodes displayed suppurative and necrotizing granulomas. Of eight previously reported cases of C. ovis lymphadenitis in man, all but one have involved inhabitants of rural Australia, most of whom had contact with sheep, an animal reservoir of C. ovis. Necrotizing granulomas were usually observed. The patient described was an American urban dweller with a history of raw milk ingestion. We believe this to be the first reported case of C. ovis lymphadenitis from the United States. C. ovis infection should be considered n the differential diagnosis of localized lymphadenitis with necrotizing and/or suppurative granulomas. In evaluation of granulomatous lymphadenitis tissue gram stain should be performed and culture of a diphtheroid organism not readily dismissed.