RESUMO
BACKGROUND Situs inversus totalis (SIT) is a rare congenital abnormality that includes mirror-image transposition of both the abdominal and the thoracic organs. It may remain undetected into adulthood until an acute medical emergency results in diagnostic imaging. This report presents a challenging case of left-sided acute appendicitis in a 45-year-old man with SIT. CASE REPORT A 45-year-old man with a medical history of gastroesophageal reflux disease, class 2 obesity, prediabetes, and elevated low-density lipoprotein cholesterol presented with severe acute abdominal pain localized in the left lower quadrant with localized tenderness, nausea, and 2 episodes of non-bloody and non-bilious emesis that started a day before the clinical encounter. Computed tomography of the abdomen and pelvis revealed previously undiagnosed congenital SIT. In addition, physical, laboratory, and radiological findings suggested early acute appendicitis with no evidence of complications. Hence, the patient was managed with an emergent laparoscopic appendectomy. Acute appendicitis was confirmed in the post-surgery histopathological examination. The post-surgery recovery was uneventful, and the patient was discharged home on the second postoperative day. CONCLUSIONS This report highlights that SIT may remain undiagnosed into adulthood and poses a challenge in the diagnosis of left-side appendicitis due to atypical symptom presentation, supporting the findings of previous case reports. Therefore, the inclusion of left-sided acute appendicitis in the differential diagnosis of abdominal pain in the left lower quadrant is warranted.