a 54-year - old male patient with main pulmonary artery ( mpa ) dilatation detected in out - clinically performed computed tomography ( ct ) and with well controlled arterial systemic hypertension was referred to our department for advanced diagnostics and for a further therapy decision to be made . his first hospitalisation due to congenital heart disease suspicion was at the age of 18 . at that time there were no clinical symptoms besides the presence of protomezosystolic murmur over the left sternal edge and cardiac apex . in chest x - ray tomography performed at that time enlargement of the left pulmonary artery was found . in those days  in 1976  atrial septal defect was suspected and the patient was referred for haemodynamic and angiographic studies . were restarted , and ct revealed mpa dilatation to 40 mm . during the present hospitalisation the patient denied the presence of any cardiovascular symptoms and confirmed regular physical activity . examination revealed only slight systolic murmur ( levine 1/6 ) over the left sternal edge . chest x - ray revealed enlargement of the left hilum probably due to enlargement of the main pulmonary artery ( fig . the right pulmonary artery ( rpa ) was enlarged up to 29 mm , and the left one was not precisely visible . right ventricule diameter and contractility were normal ( rvdd  29 mm ) without symptoms of pulmonary hypertension ( trpg  20 mmhg ) . cardiac ct revealed mpa aneurysm ( 47  40 mm in diameter ) with significant enlargement of the left ( 37  35 mm ) and right pulmonary artery ( 24  27 mm ; figs . 1 and 2 ) . potential primary causes of mpa dilatation were eliminated , such as : distal mpa stenosis , pulmonary embolism , and the presence of any pulmonary disease . coronary arteries ct scan was performed and showed no signs of left coronary artery compression with mpa aneurysm ( fig . 3 , 4 ) . additional laboratory studies excluded inflammatory and collagen disorders . according to the gathered data a diagnosis of idiopathic dilatation of the main pulmonary artery ( idpa ) was stated . at that time chest x - ray showing enlargement of left hilum probably due to main pulmonary artery dilatation main pulmonary artery dilatation ( computed tomography reconstruction ) main pulmonary artery dilatation with right and left pulmonary artery enlargement ( computed tomography study ) computed tomography scan showing pulmonary artery aneurism with no compression on left coronary artery after six months control echocardiography showed a proximal mpa diameter of 28 mm with enlargement progression of the distal segment to 51 mm and rpa to 31 mm . right ventricule diastolic diameter was also enlarged to 41 mm with preserved contractility . computed tomography study revealed progression of mpa diameters to 52  45 mm , lpa diameter to 36  27 mm , and rpa diameter to 30  26 mm . after the next four months an echocardiography study showed stable parameters of pulmonary arteries with mpa enlargement progression to 57 mm . isolated pulmonary artery enlargement , also known as idiopathic dilatation of the pulmonary artery , is a rare congenital defect with a prevalence of 0.6% of all congenital heart defects ( chd ) [ 1 , 2 ] . clinical criteria of idpa diagnosis were first presented by green in 1949 and improved in 1960 by desmukh [ 5 , 6 ] . according to them , idpa may be diagnosed if : isolated mpa diameter exceeds 30 mm with or without pulmonary arteries enlargement , there is an absence of intra or extracardiac shunt , cardiac or pulmonary disorders , arterial wall pathologies ( i.e. atherosclerosis , callosity , syphilis ) , and with normal pulmonary artery and right ventricule pressure . actually due to the availability of more accurate diagnostic tools further criteria were added : ratio of pulmonary artery bifurcation and aortic annulus diameters more than 1.4 and/or ratio of mpa and aortic annulus diameters more than 1.5 . however , there are no precisely defined normal ranges of mpa diameter . it is accepted that mpa should not exceed 30 mm or mpa diameter should not be larger than aortic diameter on the corresponding level . it should be noted that those criteria apply to pulmonary artery dilatation in patients with pulmonary hypertension but not to idpa . until now post - mortem histopathological studies showed mucopolysaccharide deposits in the tunica media of the mpa , which is similarly detected in cystic medial necrosis . thus , idpa may be caused by unidentified connective tissue pathology . in the vast majority of cases usually it is accidentally diagnosed while chest x - ray shows significant enlargement of the left pulmonary hilum . clinical manifestation involves non - specific angina , dyspnoea , exercise intolerance , cough , and haemoptysis . according to some authors , in patients with idpa a physical examination may reveal : systolic murmur over the left sternal edge ( up to 3/6 in the levine scale ) with maximal force in 2 or 3 intercostal space , the presence of pulmonary click , and 2 tone split [ 9 , 10 ] . since those symptoms are not specific final diagnostics require echocardiography with mpa diameter calculation , evaluation of valve morphology and function , and exclusion of pulmonary hypertension . the occurrence of spontaneous dissection of pulmonary artery aneurism in patients with idpa is extremely rare . reported a case of 39-year - long uneventful follow - up of a patient with untreated idpa . thus , it is crucial in the diagnostic process to exclude the possibility of secondary mpa enlargement to chd , patent ductus arteriosus , pulmonary artery stenosis , pulmonary hypertension , mpa infection ( bacterial , mycotic , tuberculotic and syphilic ) , vascular inflammatory process ( behcet disease , huges - stovin disease ) , and connective tissue defects ( marfan or ehlers - danlos syndrome ) . the main causes of death in patients with pulmonary hypertension and pulmonary artery aneurism are dissection and rapture of aneurism . some authors support the thesis that all patients with pulmonary artery aneurism should be referred for surgical intervention . others advocate that patients presenting clinical symptoms ( dyspnoea , chest pain , haemoptysis ) , dynamic progression of mpa enlargement , or dissection should only be treated surgically due to high mortality risk [ 17 , 18 ] . since the majority of data show that rupture of an mpa aneurism occurs mostly in patients with primary disease , such as connective tissue disorder , pulmonary hypertension , or mycotic infection , it remains rational to refer all symptomatic patients with secondary pulmonary artery aneurism for surgical intervention [ 19 , 20 ] . suggest that the timing of the surgical procedure in the population with pulmonary hypertension should be additionally guided with right ventricule dimension , function and presence of pulmonary regurgitation , or stenosis , regardless of mpa size . those techniques might be incorporated into idpa if the decision to go ahead with surgical treatment is made . longitudinal plication of mpa ( aneurysmorrhaphy ) may be performed without use of cardiopulmonary bypass and is relatively less technically demanding . however , plication should not be performed in patients with connective tissue disorder or chd since the risk of further enlargement of mpa is high . definitive correction may be achieved by total aneurysmectomy and repair with dacron or gore - tex graft or autologous pericardial replacement . in patients with severe pulmonary artery valve dysfunction due to pulmonary artery valve dilatation reconstruction of right ventricule outflow tract ( rvot ) might be needed . for that purpose the use of homograft , porcine aortic xenograft , or bovine jugular vein is indicated . a few authors have reported the feasibility of percutaneous coronary artery angioplasty with stent implantation due to coronary artery compression by mpa aneurism . in such cases it is recommended that precise visualisation of compressed artery segment be performed with use of computed tomography since standard angiography may not be sufficient [ 23 , 24 ] . in conclusion , in the presented case we confirmed constant progression of pulmonary artery dilatation since it was first observed more than ten years previously . however , right ventricule function has been preserved and the patient is currently free from any symptoms . idiopathic dilatation of the main pulmonary artery diagnosis is stated since other primary causes were eliminated . the heart team agreed that currently the risk of surgical intervention is higher than the potential benefit . the patient is scheduled for frequent control follow - up and will be operated if any symptoms occur .
idiopathic dilatation of the pulmonary artery ( idpa ) is a rare congenital heart disease . 
 it has been described for almost one hundred years , and numerous definitions have been proposed . 
 the idpa diagnostic criteria have not been updated for years . 
 secondary to primary disease , pulmonary artery aneurism was recognised as a lethal defect ; however , long - term follow - up of patients with idpa has not been well researched . 
 thus , indications to medical or surgical treatment are not evidence based . here 
 , we present a rare case of a 54-year - old patient with idpa , who remained under observation for 36 years without surgical intervention .