Asian Cardiovasc Thorac Ann 2006;14:e71-e73
© 2006 Asia Publishing EXchange Ltd
Pulmonary Artery Sarcoma Mimicking Massive Pulmonary Embolus: A Case Report
Bahaaldin Alsoufi, MD,
Matthew Slater, MD,
Pamela P Smith, MD1,
Tara Karamlou, MD,
Atiya Mansoor, MD1,
Pasala Ravichandran, MD
Department of Cardiothoracic Surgery
1 Department of Pathology, Oregon Health & Sciences University, Portland, USA
For reprint information contact: Bahaaldin Alsoufi, MD Tel: 1 416 364 7185 Fax: 1 503 494 7829 Email: Balsoufi{at}hotmail.com, 33, Harbour Square, # 1028, Toronto, Ontario M5J 2G2, Canada.
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ABSTRACT
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Intimal sarcomas of the pulmonary artery are rare tumors that are often difficult to distinguish from pulmonary thromboembolic disease, complicating accurate diagnosis and timely therapy. We report the case of a gentleman with a primary pulmonary artery sarcoma who presented with a massive pulmonary embolism and complete right ventricular outflow tract obstruction. The patient’s condition was successfully managed with urgent pulmonary artery thromboendarterectomy, pulmonary valve replacement, and tricuspid valve annuloplasty.
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CASE REPORT
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A 76-year-old man presented with two months history of shortness of breath, weakness and malaise. Echocardiogram showed evidence of obstruction of the right ventricular outflow tract at the valvular level, with "diaphragm-like" pulmonary valve, moderate to severe tricuspid valve insufficiency, right ventricular hypertrophy, and moderate systolic dysfunction. Computed tomography (CT) scan of the chest demonstrated a large saddle thrombus with almost complete filling of the main pulmonary trunk and both pulmonary arteries. The thrombus extended into the interlobular arteries bilaterally (Figure 1
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Figure 1. The large saddle pulmonary thrombus extending into both right and left main pulmonary arteries and their segmental branches.
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He was admitted and placed on intravenous un-fractionated heparin. Over the next 12 hours, the patient’s cardiorespiratory condition deteriorated, and he was taken to the operating room for embolectomy. Upon induction of anesthesia, he rapidly arrested. Sternotomy was performed and he was placed on cardiopulmonary bypass emergently. The pulmonary artery was noted to be hard, and a solid, rubbery mass obliterating the lumen was encountered on opening the pulmonary artery. The mass arose at the level of the pulmonary valve and extended distally to the segmental pulmonary branches bilaterally. The mass was excised entirely through an endarterectomy plane that extended to both left and right pulmonary arteries and the distal segmental branches. The posterior leaflet of the pulmonary valve was destroyed, and the remaining leaflets were thickened and fibrotic. The valve was replaced with a 25 mm pulmonary homograft, and tricuspid valve repair using a 30 mm annuloplasty ring was performed. Postoperative TEE showed a competent pulmonary valve and mild tricuspid regurgitation with overall good right ventricular function. On gross inspection, the mass was over 8 cm long, and formed essentially a perfect "cast" of the pulmonary artery from the valve into the pulmonary artery distal vasculature (Figure 2). Hematoxylin and eosin sections of the tumor demonstrated a spindle cell neoplasm with moderate nuclear atypia and a patchy myxoid background. Focal areas showed rhabdomyosarcomatous differentiation (Figure 3).
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Figure 2. The gross pathologic specimen including the mass in the main pulmonary trunk and the bifurcation as well as the distal branching into the segmental pulmonary arteries.
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Figure 3. Hematoxylin and eosin sections of the tumor demonstrated a spindle cell neoplasm with moderate nuclear atypia and a patchy myxoid background.
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The patient’s postoperative convalescence was uneventful. He refused adjuvant chemotherapy. His physical condition improved significantly with resolution of his dyspnea and malaise. Nine months later, on a follow-up CT scan of the chest, he was noted to have a recurrent mass in his right outflow tract without any evidence of metastatic disease. Upon surgical re-exposure, he was found to have recurrence at the right ventricular outflow tract which was resected with negative margins and the tract was reconstructed with a pulmonary homograft. He recovered well from his second surgery and is currently in NYHA 1 class without any recurrence of the disease.
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DISCUSSION
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Intimal sarcomas are rare intravascular malignant mesenchymal neoplasms that arise predominantly in the aorta and pulmonary artery. Sarcoma of the pulmonary artery was first described at autopsy by Mandelstamm in 1923. Since then, there have been only a few hundred cases reported in the literature. The incidence of intimal sarcoma in the pulmonary artery is twice that seen in the aorta. The tumor has a slight female predominance and presents almost exclusively in middle age adults, though the age range is broad. The reported age at presentation has ranged from 13 to 89 years. Symptoms range from nonspecific subtle worsening shortness of breath and cough to progressive right heart failure and eventual circulatory collapse. Symptoms and signs such as weight loss, fever, anemia, and digital clubbing may be subtle clues to the diagnosis.
In a review of 110 patients with primary pulmonary artery sarcoma reported in the literature, the described symptoms were: dyspnea 67%, chest pain 54%, cough 43%, and hemoptysis 22%.1 The diagnosis is often delayed and may be confused with pulmonary artery embolic disease. Very rarely, the correct diagnosis is made preoperatively.2,5,6 Most patients receive inappropriate therapy such as prolonged anticoagulation or thrombolysis for months or years prior to the diagnosis of malignancy. Laboratory tests are often nonspecific. The patient may have elevated erythrocyte sedimentation rate, thrombocytopenia, polycythemia or evidence of disseminated intravascular coagulopathy.
Electrocardiography may show right heart strain, right ventricular hypertrophy, and nonspecific ST segment changes or T wave inversion. Echocardiography can reveal the mass, or evidence of right ventricular outflow tract obstruction, however it is often not possible to accurately distinguish between a thrombus or a tumor. Chest roentgenogram findings are also nonspecific, including increased right heart size, pulmonary artery dilatation, abnormal hilar shadow, and decreased pulmonary markings. Occasionally a mass suspicious for malignant metastases can be identified. Pulmonary angiogram can show suspicious findings: a pedunculated lesion with "to and fro" motion representing the tumor on a stalk, or smooth gradual tapering of the pulmonary artery with pruning of the distal vessels have all been considered findings suggestive of malignancy.
Other imaging modalities, such as CT scan, gadolinium-enhanced MRI, or PET scan can show evidence of metastatic disease but are unable to differentiate between pulmonary artery embolus and sarcomas.2,7 The preoperative quality of life is poor because of progressive right heart failure, and survival is dismal in patients without any surgical intervention. Surgery offers the only palliative and potentially curative treatment choice for those patients.
Surgical interventions included: "shelling out" the tumor concomitant with pulmonary artery thromboendarterectomy, pneumonectomy with or without extracorporeal support, and extended resection with major reconstruction. Many tumors though are not completely resectable at the time of the diagnosis, and palliative surgery with thromboendarterectomy may be the only option. Even with surgical therapy, the prognosis is poor. The mean survival rate is 1.5 months without resection and 10 months with resection. Complete resection remains the main factor affecting survival in patients following resection. The effectiveness of adjuvant therapy remains questionable. Patients present with distant metastases in almost two thirds of reported cases; most to the lungs, but also to the liver, brain, adrenals, mesentery, and lymph nodes. In some reports, adjuvant chemotherapy and radiotherapy were effective in prolonging the survival of patients after radical resection. Survival was extended up to 65 months in one report following combined resection and adjuvant therapy.3,5 However, the results of adjuvant chemotherapy were not replicated in all studies.2,6 In addition, due to the rarity of these tumors, there are no standard recommendations regarding the type and duration of adjuvant modalities in the treatment of these sarcomas. In general, oncologists have applied the same methods used in the treatment of different soft tissue sarcomas, which varied in different eras and different hospitals. Combined heart-lung transplantation has been attempted for unresectable pulmonary artery sarcomas. However, even with successful surgical outcomes, the high incidence of metastases in those patients limits its utility.8
In summary, there is no standard practice to treat those rare tumors. It may be helpful to enroll all the patients into an international registry with treatment protocols, in order to answer some important questions regarding the indications, extent of surgery, and the role of neoadjuvant versus adjuvant therapy; with the type, duration and optimal sequence to offer the best chance of cure and prolonged survival.
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REFERENCES
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ABSTRACT
CASE REPORT
