Mysterious objects in the pleural biopsy of a patient with recurrent pleural empyema: Photo Quiz Answer: Tomato seeds in the pleural biopsy after emergency thoracotomy

Case presentation: A 66-year-old woman with a history of mitral valve disease was hospitalized because of pneumonia of the right lung with bilateral pleural effusions. Antibiotic therapy was initiated and a chest tube was placed into the right pleural cavity. The patient responded well to the treatment and was discharged 3 weeks later. Echocardiography performed during hospitalization showed that mitral valve replacement was indicated and 7 weeks later the patient underwent minimal invasive surgery with implantation of an artificial heart valve. The operation was successful but due to post-operative bleeding an emergency thoracotomy with medial sternotomy became necessary. On the following day the patient developed septic shock. An empyema of the left pleural cavity was identified as the most likely focus of infection and pleural aspirates showed growth of Enterobacter cloacae, Enterococcus avium, Pseudomonas aeruginosa and Candida albicans. Surgical revision including the placement of additional chest tubes and multiple lavages of the pleural cavity lead to a clinical and radiological improvement. However, during the following weeks the condition of the sternotomy wound deteriorated. A CT scan showed signs of sternum osteomyelitis and again drainage of a distinct pleural empyema was required. Sternal swabs grew Candida albicans in large numbers. Because conservative therapy with fluconazole and vacuum-assisted closure systems failed to improve the osteomyelitis and the empyema could not be removed by drainage alone, re-thoracotomy was performed on day 91 and 105, respectively. Biopsies were obtained during the surgical removal of pleural fibrosis and histological examination revealed several egg-like objects (Fig. 1). The patient lived all his life in Germany and travelled once to South Africa 10 years ago. The differential blood count showed no eosinophilia and IgE levels were normal. Sonography of the abdomen showed a slight hepatomegaly and normal findings of spleen and kidneys. Question What could these objects be? Figure 1: Hematoxylin and eosin (H&E) staining of a pleural biopsy showing one of multiple egg like objects. Answer: Tomato seeds in the pleural biopsy after emergency thoracotomy.