Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Pleuropulmonary paragonimiasis
- Radiologic Findings
- On chest X-ray, single pulmonary nodule involving in LUL..
CT scans at lung window setting show lobulated nodule on LUL with adjacent interlobular septal and pleural thickening.
CT scan at mediastinal window setting shows heterogenous enhancement of the pulmonary nodule on LUL. with focal adjacent pleural thickening.
On fusion PET-CT, increased FDG uptake is seen on LUL, corresponding to the pulmonary nodule. (maximum standardized uptake value = 5.1)
- Brief Review
- Pleuropulmonary paragonimiasis is a food-borne parasitic disease caused by the lung fluke Paragonimus westermani, which is endemic in Southeast Asia and the Far East. Human infection results from ingestion of raw freshwater crab or crayfish infected with the metacercaria.
P. westermani excyst in the small intestine, and the larvae penetrate the intestinal wall and enter the peritoneal space. Next they penetrate the diaphragm and pleura and enter the lung in 3? weeks, where they mature to adult flukes.
On chest radiographs, 83% of patients had pulmonary lesions (consolidation, cysts, nodule, and linear opacity) and 61% had pleural lesions (pleural effusion, hydropneumothorax, and pleural thickening).
According to Im et al. the characteristic CT features of paragonimiasis were round low-attenuation cystic lesions (5?5 mm) filled with either fluid or gas, within the consolidation. On CT, air-space consolidation was noted in 82% (14/17), nodules in 41% (7/17), linear opacities extending from the pleura to the lung in 41% (7/17), and bronchiectasis in 35% (6/17). Subpleural linear opacities or a tubular structure communicating with a cyst were suggestive of worm migration tracks.
According to Kim et al. Pleuropulmonary paragonimiasis usually manifests as a subpleural or subfissural nodule of about 2 cm in diameter that frequently contains a necrotic low-attenuation area. The constellation of focal pleural thickening and subpleural linear opacities leading to a necrotic peripheral pulmonary nodule is another frequent CT finding of paragonimiasis. Although minimal and easily overlooked, focal fibrotic pleural thickening adjacent to a pulmonary nodule can be an important clue in the diagnosis of pleuropulmonary paragonimiasis on CT.
According to a case report by Watanabe et al., pulmonary paragonimiasis can mimic lung cancer by showing a high FDG uptake on FDG PET.
- References
- 1. Im JG et al. Pleuropulmonary paragonimiasis: radiologic findings in 71 patients. AJR 1992; 159:39?3.
2. Kim TS et al. Pleuropulmonary paragonimiasis:CT findings in 31 patients AJR 2005; 185:616?21.
3. Watanabe S et al. Pulmonary paragonimiasis mimicking lung cancer on FDG-PET imaging. Anticancer Res 2003;23:3437?440.
- Keywords
- Lung, Infection, Parasitic infection,