Concurrent cor triatriatum sinister and levoatriocardinal vein in an 11-year-old boy presenting with foudroyant pulmonary edema after appendectomy: A living tribute to the mal-incorporation theory

Cor triatriatum sinister (CTS) is a rare cardiovascular malformation, in which the left atrium (LA) is separated by a membrane into the proximal and distal LA chambers (1). Levoatriocardinal vein (LACV) is an even rarer vascular anomaly that connects the LA (or tributaries of pulmonary vein) with the left innominate vein (an embryologic derivative from the cardinal system) (2). Development of the pulmonary vein and systemic venous sinus are spatiotemporally correlated during embryogenesis (3). Here, we report a case of an 11-year-old boy unexpectedly presenting with acute pulmonary edema after appendectomy. Echocardiography and chest computed tomography (CT) revealed a combination of CTS and LACV, which were then surgically corrected. We briefly reviewed the English literature reporting the pediatric patients with concurrent CTS and LACV, compared their clinical profiles with ours, highlighted the pathomechanism of a delay onset of clinical manifestations in our patient, and provided an anatomical feature indicating the mal-incorporation theory for the embryogenesis of CTS.