Introduction: Subhepatic appendix is most often due to an anomaly of rotation of the primary intestine occurring during embryogenesis. This ectopic topography associated with advanced age can be a serious diagnosis problem at the stage of appendicitis or appendicular peritonitis.
Case presentation: We report the case of a 60-year-old melanoderm man, with a history of urinary pathology and peptic ulcer, referred from a health district for abdominal pain of the right hypochondrium evolving for about 5 days, secondarily generalized, in whom we suspected peritonitis, the etiology of which remains to be determined. During the surgical intervention, after preoperative resuscitations measures, a phlegmonous perforated appendix was found under the liver. No postoperative complication was noted, and he was discharged home 8 days after his operation.
Conclusion: Subhepatic appendicular peritonitis occurring in an elderly patient poses enormous diagnostic problems. When faced with right upper quadrant pain, considering acute ectopic appendicitis would significantly reduce complications.
Keywords: Case report; Embryogenesis; Peritonitis; Subhepatic appendix.