[Tularemia lymphadenitis. An emerging differential diagnosis of necrotizing granulomatous cervical lymphadenitis]

Tularemia is emerging as an important differential diagnosis of necrotizing granulomatous lymphadenitis, particularly in the head and neck region. The causal organism, Francisella tularensis is a Gram-negative coccoid bacterium. Tularemia usually presents with necrotizing granulomatous purulent lymphadenitis featuring multiple mostly small granulomas with geographic necrosis bordered by palisades of histiocytes. Diagnosis is mainly based on these characteristic but non-pathognomonic histological features in conjunction with negative tests for mycobacterial infections and serological confirmation of tularemia-specific antibodies or detection by polymerase chain reaction (PCR). This article describes our experiences with five patients with tularemia lymphadenitis and gives an overview of the diverse histopathological features and the differential diagnosis of this uncommon but possibly underrecognized disease.