[The solitary echinococcal cyst--a rare cause of a round pulmonary focus]

A 29-year-old man from Kazakhstan presented with right-sided chest pain, cough, whitish sputum and a temperature up to 38.5 degrees C. He had been working in an animal farm for the previous two years.

Laboratory tests showed increased inflammatory parameters (WBC 15.9 gpt/l with an increased proportion of band and segmented granulocytes, C-reactive protein (242.3 mg/dl). Chest radiogram showed an infiltration and effusion in the right base judged to be due to pneumonia. In addition there was a round homogeneous mass, 2.5 cm in diameter, at the lateral thoracic wall in the 8th lower lobe segment. Computed tomography (CT) of the lung and mediastinum confirmed these findings. Bronchoscopy, echocardiography, upper abdominal sonography and CT of the skull revealed no other space-occupying lesion.

The right-sided pneumonia was successfully treated, at first with ceftriaxone (i.v.), later with ofloxacin (by mouth). An echinococcal cyst was considered especially because of the patient's profession in Kazakhstan in the differential diagnosis of the right-sided round mass and confirmed by an indirect haemagglutination test giving an antibody titre of 1:1024. In response a thoracotomy was performed and the mass, histologically an echinococcal cyst (E. granulosa), resected. There were no other cysts. There was no explanation for the right-sided pneumonia.

Even though Echinococcosis is rare in Central Europe, it should be included in the differential diagnosis of a round pulmonary mass. A detailed history, especially with regard to occupation and country of origin, is essential. Serological tests for specific Echinococcus antibodies, together with usual imaging procedures, will usually and quickly provide the diagnosis.