INTRODUCTION:This case report expands the differential diagnosis of a CT scan showing unilateral intersitial marking with associated mediastinal lymphadenopathy beyond lymphangitic carcinomatosis.
CASE PRESENTATION:A 19 year old man, with a remote history of asthma as a child with no symptoms for several years ,who was in his usual state of health when he developed the sudden onset of right sided chest pain and shortness of breath. He denied any cough, fever ,hemoptyosis or weight loss. He also denied any known sick contacts or known exposure to tuberculosis. He works in a law firm and denied any tobacco or drug use. On admission to hospital temperature was 100.2, heart rate 90, blood pressure 118/59, temperature 98.7, respirations 20, pulse oximetry 97% on room air. PHYSICAL EXAMINATION and LABORATORY DATA: unremarkable including immunoglobulins, H.I.V and vasculitic screen EKG: Sinus tachycardia with a rate of 108 and no ST-T wave changes. Chest CT-PA revealed no pulmonary embolus but a right hypoplastic lung with right sided unilateral mediastinal lymphadenopathy , pleural effusion and prominent interstitial marking . Pulmonary function testing was unremarkable except a mildly reduced diffusing capacity. The pleural effusion was not felt to be large enough to undergo thoracentesis and the clinical concern was lymphangitic carcinomatosis despite the his young age.Of note,the radiologist remarked on a septum within the left atrium dividing the right pulmonary vein from the left but the significance of this was yet to be recognized. As a result, he underwent broncoscopy and transbronchial biopsy.During which,it was noted that there was prominent varicosities on the surface on the right lung which bled easily.Biopsy revealed prominent submucosal capillaries and mild interstitial chronic inflammation and alveolar macrophages.These results suggested pulmonary venous hypertension predominantly affecting the hypoplastic right lung This prompted investigations into a possible cardiac abnormality.Transesophageal echo revealed a membrane in the left atrium obstructing right pulmonary venous inflow resulting in rt pulmonary venous pressure of 25-30mmHg. This appearance is consistent with cor triatriatum. Cardiac MRI demonstrated, on first pass post-contrast imaging, filling of the proximal chamber in the left atrium was significantly delayed relative to filling of the distal chamber. This is consistent with slow flow in the right pulmonary vasculature. Moreover, phase contrast imaging demonstrates significantly asymmetric blood flow in the branch pulmonary arteries, with approximately 15 to 20 times more in the left pulmonary artery than the right. The patient underwent an unremarkable surgical excision of the septum and three month follow up cardiac MRI revealed normal symmetric pulmonary artery and venous enhancement and normal biventricular function.
DISCUSSIONS:Cor triatriatum, first described in 1968 by Church, is a rare congenital cardiac anomaly. It constitutes approximately 0.1% of the children with congenital heart disease. It results from failure of resorption of the common pulmonary veins during embryogenesis. The condition is characterized by the presence of a fibromuscular membrane dividing the LA into two chambers—a superior posterior chamber and an inferior anterior chamber. Routine cardiac catheterization and angiography have been proven unreliable in differentiating cor triatriatum from other causes of left atrial inflow obstruction. Standard transthoracic echocardiography in adults also has its limitations in imaging posterior structures, and hence may not allow complete characterization of the membrane or the flow across the orifice in the membrane. A definitive treatment for cor triatriatum is complete surgical excision of the membrane, which has shown excellent long-term results, with 85% survival without recurrence.
CONCLUSION:This is an unique example of unilateral pulmonary venous hypertension resulting from cor triatriatum causing hypoplastic lung with mediatinal lymphadenopathy and chronic intersitial inflammation and edema.
DISCLOSURE:Brian Casserly, None.