Discussion:
Hydatic cysts of the heart are extremely rare with an incidence of
0.02-2% and these cysts are barely affect pulmonary
arteries.1 Despite being rare, the sequences of
pulmonary artery involvement such a pulmonary embolism a pulmonary
hypertension, rupture and anaphylaxis or cardiac arrest are
life-threatening.3 Several explanation has been
described to contribute to the involvement of pulmonary artries:
1.migration of the larvae into the artery wall through “vasa vasarum”,
2.larvae entering the lumen as a result of direct damage from lung
parenchyma, 3.blood dissemination through liver or other organs.
H Alper et al. reported a patient with recurrent hydatic cysts involving
several organs that undergone several operations. The patient’s
manifestation was chronic dyspnea that later was diagnosed via MR and
CT-scan as occlusion of pulmonary artery due to rupture of an intramural
cyst and thrombosis formation in the lumen; The thrombosis was removed
by surgical intervention.1 Another possible mechanism
of thrombosis is the rupture of cysts locatedin the right heart
chamber.4 Arwa et al. reported a 86-year-old female
with previous liver hydatic cyst; Four years later the patient presented
with productive cough and dyspnea. The radiologic findings on MRI and CT
demonstrated several multiseptate cysts in the lumen of right pulmonary
artery besides several primary cysts in the lung
parenchyma.5 These cases showed the presence of
secondary hydatic lesion in the lumen as a result of simultaneous cysts
in other primary organs. Only Aysegul S et al. reported an intra-luminal
cyst with obstructive effect on left pulmonary artery and its branches
found onendobronchial US investigation which seemed to be a primary
cyst.3
Diagnosis of hydatic cysts is based on radiologic and serologic
findings.4 Ultrasonography, plain radiographs, MRIs
and CT-scans or a combination of these methods are used based on the
clinical situation. Magnetic resonance features of hydatic cysts on T2
images include spherical shape, with hyposignal rim on the outside (host
reaction) and central signal similar to cerebrospinal
fluid.1 Computed tomography studies also show cysts
fluid attenuation with defined borders and enhanced contrast on the
surrounding tissue.6
Symptoms of primary lung cysts might remain silent for years and the
cysts might be the incidental findings of radiographic investigations.
Symptomatic intact cysts in the lung parenchyma might represent with
cough, hemoptysis and chest discomfort.7 Due to cyst’s
slow growth and formation of collateral blood perfusion, hydatic cysts
in the pulmonary artery remain asymptomatic until obstruction
occurs—that obstruction could be due to mass effect or rupture and
subsequent thrombosis.5, 8 The decrease in the
pulmonary flow due to obstruction or mass effect on bronchi explains the
dyspnea.3 Regarding to the current COVID-19, our case
was initially misdiagnosed as SARS-COV2 infection. Several factor led to
inaccurate initial COVID-19 diagnosis like the pandemic precautions,
lack of previous hydatic cyst history, shorter duration of symptoms and
clear initial assessments in the first hospital. However, negative
RT-PCR and CT-scan findings ruled out COVID-19 infection.
Lack of sufficient evidence and standandardized protocols limits the
options of treatment. It is suggested that the surgical removal is
treatment of choice in cases with life threatening obstruction of vital
vessels. 1, 5, 9
The hydatic cysts of the pulmonary artery are rare—but
life-threatening—and limited to case reports. Most of these cysts are
secondary to cysts in the lung or the liver and found in the intramural
or luminal space. In this case the patient with no history of hydatic
cysts in the lung parenchymarepresented symptoms such as dyspnea and
shortness of breath. Regarding to the pandemic and symptoms that
mimicked COVID-19, the patient was misdiagnosed as COVID-19 infection.
Our report shows that primary hydatic cyst with mass effect in the extra
luminal surrounding of pulmonary artery is a possible diagnosis that
should be considered and investigated through radiographic evaluations.
The treatment choice is made based on patient situation to relieve
symptoms which in this case were successful surgical removal.