Accessory fissures represent a variation of the normal lung anatomy. Incomplete development or even the absence of the major or minor fissures can lead to confusion in distinguishing adjacent lobes. This report aims to present a rare intraoperative finding of an anatomic malformation of the right lung in a 19-year old male patient with recurrent pneumothorax who underwent a surgical repair. An accessory fissure which was separating the superior segment of the lower lobe from the basal segments gave to the whole lung the unique image of a four-lobed one. A profound knowledge of the accessory fissures, even if they are incidentally discovered, is of pivotal importance for the thoracic surgeon and leads to optimal operative assessment and strategic planning.

BackgroundAnatomic deviations, especially those detected during the course of an operation, are medically intriguing, as they raise concerns about their clinical significance and putative complications.Case presentationWe present, to our knowledge, for the first time a case of an anatomic deviation in the form of a second right atrial auricle in a 70 year-old, coronary bypass-operated male Caucasian patient of Greek origin. No complications were noted intra-or postoperatively.ConclusionsA second right atrial auricle was found intraoperatively, without causing any clinical complications, or obstructing the normal course of a surgical procedure.