Lymph node infection by Trichomonas tenax: Report of a case with co-infection by Mycobacterium tuberculosis

In an 82-year-old woman, presenting with fever and asthenia, cervical adenopathy was noted. Clinical and radiological investigations were fruitless. Laboratory examinations detected a refractory anemia. The lymph node was excised and showed numerous trichomonads on touch preparations. Histologically, the node showed caseous necrosis and macrophagic reaction. Diagnosis of lymph node infection by Trichomonas tenax was made. Three weeks later, culture of the node showed Mycobacterium tuberculosis and let us conclude co-infection. T tenax is usually regarded as a harmless saprophyte of the oral cavity. This exceptional observation shows for the first time an invasive potential of T tenax. It raises questions about links with tuberculosis and refractory anemia. HUM PATHOL 31:1317-1321.