3 - Unusual cause of pulmonary embolism in children

Description of Clinical Presentation: 13-year-old girl presented with one acute episode of loss of consciousness for about 1
minute in duration. Prior to this, she had few episodes of chest pain and dyspnea on
exertion.

Diagnostic Techniques and Their Most Important Findings: IMAGING FINDINGS

Echocardiogram done  showed solid cystic lesion measuring 31 x 20 mm  attached to the interventricular septum within the right ventricle .The differentials considered where a cardiac tumour, hydatid cyst or infective endocarditis.

4 chamber and short axis cine images of cardiac MR  confirmed the presence of  immobile, multiloculated cystic lesion attached  to the interventricular septum on the RV side, protruding into the chamber. The lesion abuts the septal leaflet of the tricuspid valve, however there was no protrusion into the right atrium. T2 weighted images of the thorax showed multiple hyperintense lesions  with hypointense rim in both lungs which are of similar morphology to the lesion in the right ventricle. There was also similar T2 hyperintense multiloculated lesion identifed in the left descending pulmonary artery which was occluding the lumen and appeared as hypodense filling defect in the CT pulmonary angiogram. Hypointense membrane like structures noted in the subsegmental branches of right lower lobe.
These imaging findings were characteristic of  hydatid cyst which were primarily located in the right ventriclewhich underwent spontaneous rupture and pulmonary embolism.
There were also subpleural intermediate intense lesions in the lower lobes, which did not have the signal characteristics of the other lesion and appeared as subpleural nodular consolidations suggestive of pulmonary infarct in the CT pulmonary angiogram

FINAL DIAGNOSIS: Spontaneous rupture of right ventricular hydatid cyst with pulmonary embolism
MANAGEMENT: Patient was started on antihelminthic therapy. The patient's relatives deferred surgical excision of right ventricular lesion.

Learning Points from this

Case: Cardiovascular echinococcosis needs to be considered in the differential of intracardiac lesions in children in endemic region
Cyst projecting into the cardiac chamber can undergo spontaneous rupture in 40% of cases, resulting in embolization into the pulmonary circulation or systemic circulation and parasitic dissemination into lungs and other organs.
Characteristic signal intensity of hydatid cysts gives the diagnostic clue.