Situs inversus totalis (SIT) is an uncommon congenital disease in which the positions of the chest and abdominal organs are reversed.1Situs inversus (SI) is an autosomal recessive genetic condition that occurs in only about 0.001%–0.01% of the general population.2 This rare genetic anomaly is usually described or diagnosed by chance during chest or abdominal imaging procedures. We report a case of right pulmonary atelectasis in which the heart, spleen and liver were located right of midline.

A 46-year-old man, non-smoker with no particular complaints was referred to our department due to an abnormal chest X-ray showing dextrocardia and homogeneous opacity in the mid-right lung. Chest computed tomography (CT) showed segmentary atelectasis, extending from the right lower lobe to the right middle lobe (Fig. 1). Heart and spleen were also observed right of midline, while the liver was on the left. These findings were consistent with SIT. Fiberoptic bronchoscopy revealed the lack of an upper lobe in the right lung, but it is interesting to note that the structure of the upper lobe of the left lung was normal, i.e., it had 3 segments; apical, anterior and posterior. Bronchoalveolar lavage and cytology were normal. Bronchoalveolar lavage and aspirated fluid were negative for acid-alcohol resistant bacilli and Lowenstein culture for tuberculosis was negative. No clinical or radiological changes were observed after 6 months of follow-up.

Fig. 1.

Chest computed tomographpy showing segmentary atelectasis extending from the right lower lobe to the right middle lobe.

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SI is an uncommon congenital transpositional anomaly in which the organs of the abdomen develop in the wrong place. It occurs at a ratio of men to women of 3:2.3 In the normal arrangement, or situs solitus, the trilobar lung, the liver, the gall bladder and other internal organs are on the right side, but in SI they are on the left. The heart may be on the left on the right.4

In our case, SIT was defined with segmentary atelectasis of the right lung and the development of the right upper lobe in the area of the left upper lobe. To our knowledge, this combination has never been described in the worldwide literature. Sarkar et al.5 are the only authors to have reported a case of unilateral pulmonary hypoplasia associated with abdominal situs inversus in a 2-month-old infant.

In conclusion, SI is diagnosed fortuitously during a chest and abdominal imaging study. In these cases, pulmonary atelectasis in the right upper lobe of the left lung may be observed.