Primary pulmonary artery sarcoma (PPAS) is a rare tumor originating from the intimal
mesenchymal cells of the pulmonary artery with an incidence of 0.001–0.03% and is
usually fatal [1]. The diagnosis is difficult and delayed in most cases. It usually
presents in adults (almost equally in males and females), with median age of presentation
of 50 years [2]. Newer imaging techniques could allow early diagnosis in patients
with symptoms of pulmonary vascular obstruction [3]. Surgical resection improves clinical
symptoms, offers the only chance of cure and is performed in many cardiothoracic clinics.
The PPAS spreading to lobular branches of pulmonary artery (PA) represents an especially
serious surgical challenge.
A 58-year-old female patient was referred to our unit in December 2016 complaining
of dyspnea on moderate physical exertion and unproductive cough starting 2 months
prior to admission. Transthoracic echocardiography revealed a mass formation of 62/24
mm in the pulmonary trunk, fused with the valvular leaflets. Third-degree tricuspid
valve regurgitation was recorded as well. Aortic and mitral valves showed no significant
change, with left ventricular ejection fraction (LVEF) of 62%, and right ventricular
ejection fraction (RVEF) of 42%. Laboratory findings revealed no significant changes.
Computed tomography angiography (CTA) showed a negative dynamic in comparison to CT
data of a month earlier: the tumor spread from the bifurcation of the pulmonary trunk
by 5 mm to the left branch of the pulmonary artery, to the bifurcation of the right
branch of the PA and up to 10 mm to the valvular space of the right ventricular outflow
tract (Fig. 1 A). Tumor emboli in the segmental branches of the PA were also seen.
In the lung parenchyma, foci appeared to have increased in size: 4 mm in S6 on the
right (+3 mm), 6 mm in S3 on the left (+1–2 mm), 7 mm in S6 on the left (newly formed).
Positron emission tomography (PET) confirmed the presence of metabolic-active formation
in the pulmonary truck spreading to both PA and secondary changes in S6 of the right
and in S3 and S6 of the left lung. In this case changes in the lungs were assumed
as secondary to primary sarcoma of the PA.
Fig. 1
A – Preoperative CT scan. B – Postoperative CT scan; ligated branch of the common
iliac artery (arrow). C – Intraoperative reconstruction photo
RPA – right pulmonary artery, LPA – left pulmonary artery, PV – pulmonary valve, *PPAS
tissue.
Surgery was performed on December 28, 2016 through median sternotomy. Before institution
of cardiopulmonary bypass (CPB) and following a revision of the lungs, an atypical
resection of the foci in S6 of the right lung and in S3 and S6 of the left lung was
performed. Upon opening the pericardium, about 150 ml of fluids was drained with subsequent
sudden disturbance in hemodynamics with systolic pressure dropping to less than 50
mm Hg, followed by an increase in the central venous pressure and asystole. Direct
cardiac massage was performed and CPB was started. Under a total operative time of
380 min (myocardial ischemia time of 181 min) and hypothermia of 26°C, thromboendarterectomy
from both PA branches with complete replacement of the pulmonary trunk by pulmonary
trunk allograft (PTA, ring diameter 28 mm) was performed. Annuloplasty repair of the
tricuspid valve by De Vega was also performed. Due to insufficient length of the right
branch of the PTA, around 85 mm in length of bifurcation of the abdominal aorta allograft
(BAAA, 20 mm in diameter) was anastomosed to the lobular branch of the PTA. To fit
the diameter of one iliac branch of the BAAA, the right upper and lower lobular PA
branches were sutured together for a suitable anastomosis, while the other iliac branch
of the BAAA was ligated (Figs. 1 B, C).
Perioperative blood replacement therapy – 5 doses of erythrocyte mass, 5 doses of
10% albumin solution, 3 doses of Octaplas (a pooled human plasma solution, Octapharma
Pharmazeutika Produktionsges m.b.H., Vienna, Austria). The patient was extubated after
13 h but remained in the intensive care unit for 5 days due to moderate respiratory
failure. Postoperative chest X-ray showed subsegmental atelectases of both lobes on
both sides, as a consequence of thromboembolism of small branches of the PA in combination
with inflammatory infiltration. Postoperative echocardiography (day 13): no detectable
tumor mass in the PA, aortic, tricuspid and mitral valve – trivial regurgitation,
LVEF 62%, PVEF 46%, maximum gradient across PA valve 3 mm Hg with mild regurgitation,
average PA pressure 36 mm Hg. The patient received long-term antibacterial, anticoagulant
therapy and was discharged on the 20th day after the operation in a satisfactory condition.
Pathology study confirmed the presence of PPAS, intimal type, with myofibroblastic
differentiation, G3. Tumor growth in the margins of resection, and metastatic lesion
of the right and left lungs were revealed (Fig. 2). Immunohistochemical study: SMA
++, Des (–), Vim +++, CD31 –/+, CD34 –/+, FVW –/+, Ki67 – 25%.
Fig. 2
A – Gross image of explanted tumor. B – Mitotic activity in the tumor (arrows), H
+ E, 400×. C – Tumor metastasis in the lung, H + E, 100×
Postoperatively the patient initially received 8 courses of adjuvant polychemotherapy
(docetaxel 120 mg and gemcitabine 100 mg) from February, 2017 to October, 2017 with
a negative effect according to CT data (enlargement of lung foci from 5 mm to 22 mm).
Subsequently, the patient was switched to another polychemotherapy (mesna 400 mg and
ifosfamide 1.2 g/m2) and received 6 courses, starting from October, 2017, with positive
radiological results (decrease in lung foci from 9 × 14 mm to 6.3 × 9 mm in S5, from
5 mm to 3.5 mm in S9–S10, from 7 mm to 4 mm in S6 of the right lung).
Echocardiography 18 months postoperatively was not significantly different from that
of the early postoperative period. The patient had a CT control on November, 2018,
roughly 23 months after the operation, with further reduction in lung foci size.
The PPAS is an uncommon malignant tumor of the cardiovascular system. Moritz Mandelstamm
first described this disease in 1923 [1]. Since then, around 400 confirmed PPAS cases
were reported with a slight predilection for men with the majority of cases occurring
in patients around 50–55 years old [2]. Symptoms vary depending on the tumor histology,
size and location. Common symptoms include dyspnea, cough, chest pain, malaise, and
anorexia. Occluded circulation induced abnormal coagulation, arrhythmias, and pericardial
effusion tamponade. Signs indicative of neoplasia, such as weight loss, clubbing,
anemia, and an elevation in the erythrocyte sedimentation rate, may occasionally be
found. Systolic murmur of the PA valve area origin and signs of dysfunctional right
ventricle can be frequently observed during physical examination. Usually, a chest
radiograph can detect hilar enlargement and the echocardiography can locate the mass
in the vessels. In clinical practice PPAS is extremely rare, whereas the prevalence
of pulmonary embolism is fairly high. Due to similar symptoms and echocardiographic
findings, PPAS is often confused with pulmonary embolism [2, 4]. The diagnosis of
PPAS is often made during the operation when the tumor mass was thought to be chronic
pulmonary emboli originally. Chest CT scan and cardiac MRI are helpful anatomically
while PET scan has been proven to be more potent to differentiate these two diseases
and to characterize the features of tumor mass in the PA. Due to limited effects of
chemotherapy or radiotherapy, surgical resection has been proven to be the most beneficial
alternative for the treatment of PPAS [4, 5].
Fures et al. stated that the effects of radiotherapy and chemotherapy after surgical
treatment of PPAS are not clearly defined [6]. Mattoo et al. considered that if the
disease was diagnosed early before the occurrence of distal metastasis or involvement
of adjacent mediastinal structures, the intimal sarcoma could be cured by total resection
[7].
In our case, the patient received 14 courses of polychemotherapy and there is no evidence
of tumor recurrence in the pulmonary artery, along with a decrease in size of metastatic
foci in the lungs.
The uniqueness of this case is the modification of composite allograft (PTA and BAAA)
implantation following complete resection of the pulmonary trunk with both branches
of the PA and thrombectomy due to severe intraoperative thromboembolism. Such a composite
conduit is especially useful in the case of PA major branches’ length deficiency and
also if lobular branches are affected by PPAS. If lobular branches require a prosthesis,
BAAA is a readily available biological bifurcation prosthesis.
We chose the BAAA over xenograft, xenopericardium patch, Dacron and PTFE prostheses
as the plastic nature of the allograft was considered to reduce the risk of infection,
hemorrhage and thrombosis.
In this case, resection of pulmonary metastases before CPB institution was performed
to reduce the risk of bleeding into the pulmonary parenchyma following full heparinization.
We chose to ligate one branch of the BAAA instead of suturing it due to low pressure
in the PA and to reduce myocardial ischemia time under CPB.
Overgrowth of PPAS into both branches of the PA up to the lobular branches cannot
be considered as a contraindication to surgical treatment. In such cases multimodal
therapy, comprising PA and lobular branches’ replacement with a composite allograft
(PTA and BAAA) in conjunction with adjuvant polychemotherapy can be considered as
the treatment of choice. Composite allograft implantation, described in this paper,
involves replacement of the PA with both its branches and is associated with low risk
of bleeding and thromboembolic and infectious complications.
Disclosure
The authors report no conflict of interest.