Colorectal cancer and situs inversus totalis: case report

Situs inversus totalis is a rare congenital condition that occurs in one out of 4000–20000 people, characterized by complete transposition of the thoracic and abdominal viscera1-14. In contrast, situs solitus is a term that refers to the normal arrangement of body organs. Any disposition of organs between these two extremes is designated by situs ambiguous, situs transversus or situs inversus partialis8. The etiologic nature of this anomaly is not known. This condition is typically associated with normal life expectancy unless a gastrointestinal or cardiac anomaly is present 2,8. The typical cardiac anomaly has from 3–5% incidence, is transposition of the great vessels, and 80% of these patients have a right sided aortic arch5. Other vascular anomalies are variation of celiac trunk and superior mesenteric artery4. There are also anomalies of the gastrointestinal system to include biliary tree atresia, duodenal atresia, preduodenal portal vein, colonic aganglionosis, malrotation of the intestine, polysplenia/asplenia, anular pancreas, diaphragmatic hernia and others4,5. Moreover, it may be associated with clinical syndromes, like Kartagener’s (situs inversus, chronic rhinosinusitis and bronchiectasias)14. This anomaly is not a premalignant condition. However, many cases of malignant neoplasms and situs inversus totalis have been reported, especially gastric cancer8. Association between colorectal cancer and situs inversus totalis is rare.