[Portal vein thrombosis and Prevotella melanigenica revealing an appendicular abscess].

Introduction: The misleading aspects of appendicitis are multiple. We report an observation, original not only from a clinical and bacteriological point of view but also because of the presence of a portal vein thrombosis.

Observation: A 48 year-old man was hospitalized for prolonged fever. Examination revealed a thrombosis of the portal vein. Several hemocultures were positive for Prevotella melaninogenica. There was no abnormality in blood crasis and/or thrombophilia. Since the digestive and endoscopic control was negative, as well as the scanographic and sonographic exploration of the appendix area, exploratory laparotomy was performed and revealed an abscess on the appendix, which was responsible for the clinical, biological and radiological images. Appendectomy led to complete, immediate and permanent regression of the fever.

Comments: The discovery of a Prevotella-type germ disputes the pathogenicity of such an anaerobic germ, at distance from a site where it is normally saprophyte.