INTRODUCTION: Vascular invasion of tumor is well described in Lung cancer. We wish to report a case of lung cancer which was extending intravascularly into the pulmonary artery masquerading as a pulmonary thrombus. Pulmonary endoarterial biopsy was obtained via a percutaneous transvenous catheter which confirmed the diagnosis of recurrent lung adenocarcinoma. To the best of our knowledge, this is first reported case of lung cancer diagnosed with this novel approach.
CASE PRESENTATION: A 76-year-old male with prior history of Non-small cell lung cancer (NSCLC) status post right middle and lower lobectomy and partial right upper lobe wedge resection presented with gradually progressive dyspnea and cough. Initial CT chest failed to reveal any new suspicious pulmonary or mediastinal lesions. Progressive symptoms warranted close follow up. A repeat CT chest 6 months later revealed mild fullness in the right hilar area, but a subsequent Positron Emission Tomography scan failed to reveal any abnormalities. After a period of another six months, CT chest revealed a decrease in caliber of right upper lobe and right main pulmonary arteries. MRI of the chest showed an intravascular mass suggestive of a thrombus. Follow up CT chest with contrast confirmed proximal extension of this lesion into the main Pulmonary artery completely occluding the right pulmonary artery raising the question of thrombus versus tumor (Figure 1). The lesion was not easily amenable to a surgical approach. Therefore, a pulmonary angiogram was performed and biopsy specimens were taken with the use of an endovascular biopsy catheter which confirmed the diagnosis of recurrent NSCLC (Figure 2).
DISCUSSIONS: Direct intravascular extension of bronchogenic carcinoma is not uncommon. Lung cancers unlike other visceral cancers are more prone to vascular invasion and it is thought to be related to the relatively low pulmonary arterial pressures which may render itself more susceptible to neoplastic penetration. Macroscopic vascular extension is relatively rare and has been reported to portend a poor outcome. In this case, the tumor recurred inferior to Right upper lobe Pulmonary artery and invaded the right pulmonary artery resulting in complete occlusion of the lumen mimicking a pulmonary thrombus. Yamaguchi et al, reported a case series of Lung carcinoma with polypoid intravascular invasion of main pulmonary artery, but the diagnosis could not be made pre-operatively 1. The location of tumor and patient's limited pulmonary reserve made surgical intervention a high-risk procedure. Therefore, a novel endovascular approach was adopted. Very few cases of this diagnostic approach have been reported in literature. Endovascular approaches have been used to diagnose lung cancer with superior vena caval invasion, right and left atrial tumours and pulmonary artery leiomyosarcoma. To the best of our knowledge, this is the first reported case of NSCLC with intravascular extension in to the pulmonary artery that was diagnosed with a pulmonary endoarterial biopsy. A high-risk surgical intervention was obviated by this procedure.
CONCLUSION: When neoplastic vascular invasion of the pulmonary artery or great veins is suspected, trans-vascular approach to biopsy should be considered. It appears to be safe and can provide diagnostic tissue while also assisting with staging of the patient.
DISCLOSURE: Todd Gienapp, None.