Left Isomerism With Normal Bronchopulmonary Anatomy: Broadening the Heterotaxy Spectrum

Abstract

Situs ambiguous is a rare congenital condition characterized by the abnormal arrangement of thoracoabdominal organs along the left-right axis. This condition often presents as either left or right isomerism, leading to complex anatomical variations and associated clinical challenges. We present the case of a 44-year-old female who was incidentally discovered to have situs ambiguous with polysplenia and left atrial appendage isomerism during the evaluation of abdominal pain and urinary symptoms caused by a ureteral calculus. Notably, the patient exhibited normal bronchopulmonary anatomy. The patient underwent a ureteroscopy, laser lithotripsy, stone extraction, and right ureteral stent placement. The patient was discharged shortly thereafter. We believe our case underscores the critical importance of recognizing the potential dissociation between thoracic and abdominal isomerism. It also highlights the need for further investigation into the embryological processes that contribute to these unusual presentations.

Figure 1

Coronal noncontrast CT demonstrates kidney stone in the right ureter (red arrow).

Figure 2

Axial noncontrast CT shows the liver in the LUQ (blue circle), the stomach in the RUQ (green triangle), polysplenia (white arrows), a circumaortic left renal vein (red arrow), and a prominent azygos vein (yellow curved arrow).

Figure 3

Coronal noncontrast CT demonstrates the midline position of the cecum and ascending colon (white arrow) and a short transverse colon present in the RUQ (red arrow).

Figure 4

Sagittal CT shows (a) the normal configuration of the bilobed left lung and (b) the normal configuration of the trilobed right lung.

Figure 5

Coronal CT demonstrates normal eparterial right upper lobe bronchus (blue arrow) and hyparterial left upper lobe bronchus (red arrow).

Figure 6

Coronal CTA demonstrates long and narrow bilateral atrial appendages suggesting left isomerism (blue arrows).