MRI of intimal sarcoma of the pulmonary arteries.

A 38-year-old woman presented with left lower chest pain. At the age of 3 years, a commissurotomy of the pulmonary valve and infundibulectomy was performed to correct severe infundibular pulmonary stenosis. The initial thoracic CT diagnosed bilateral pulmonary embolism. Echocardiography revealed a filiforme mass in the pulmonary artery 33 mm in length, floating in the right outflow tract, suggesting a pulmonary sarcoma. In addition, a moderate pulmonary valve insufficiency with mild stenosis was diagnosed. Cardiac magnetic resonance (CMR) confirmed the mass in the left pulmonary artery (PA) with floating parts and a small mass in the right PA (Figure 1) and provided complementary findings identifying the mass as tumor, differentiating it from chronic thromboembolism. In particular, perfusion CMR1 demonstrated blood flow in the mass (Figure 2A and 2B), and late contrastenhanced CMR revealed highand low-signal territories in the tumor suggesting heterogenous cell-rich and celldepleted components of the mass (Figure 3).2 Histology as shown in Figure 4 showed the mass to be an intimal sarcoma with widespread vascularization with cellrich and myxoid, cell-depleted regions. The patient underwent an open surgical resection of the pulmonary mass including repair of the PA and pulmonary valve replacement. An additional chemotherapy with adriamycin/Holoxan and uromitexan was started 4 months later, and a lobectomy of the right upper pulmonary lobe was performed for metastatic disease. One year after being diagnosed, the patient is still alive and has started working again. The clinical presentation and radiological features may mimic pulmonary embolism.3 The CMR criteria suggesting tumor rather than emboli are (1) detectable tissue perfusion and (2) heterogenous enhancement on late CMR imaging resulting from differences in tumor cellularity.2 Intimal sarcoma is a rare, highly malignant neoplasm that typically arises from the central pulmonary arteries. The prognosis must be regarded as extremely poor. Most patients die within months of right heart failure secondary to outflow obstruction or distal (thrombo) embolism. The main treatment for sarcoma is aggressive surgical resection, but, even after heart and lung transplantation, recurrent metastases in noncardiac organs occurred in half of the patients. The role of adjuvant radiation and chemotherapy remains unclear.3,4 CMR provides important information, readily distinguishing tumors such as intimal sarcoma from thrombotic masses in the pulmonary arteries, which are notoriously difficult to discriminate with conventional diagnostic approaches.