Unusual Behavior of Intestinal Spirochetosis: A Case Report

Human intestinal spirochetosis is a rare clinicopathological condition characterized by the presence of spirochetal microorganisms on the surface of the colorectal mucosa and, in some cases, by their invasion into the lamina propria. The most frequent cause of this infection is immunocompromised status. Our case report describes a patient with relevant symptoms and endoscopic alterations, but limited invasion by spirochetes, as shown by histological analysis of ileal and colonic specimens. After histological examination, metronidazole was initiated. This resulted in rapid and complete resolution of the symptoms, which demonstrated an infectious etiology. The peculiarity of our case is that the clinical and endoscopic appearances were typical of the aggressive behavior of the disease, but histological samples showed only superficial colonization of the colonic epithelium without clear invasion of deeper layers. This case report emphasizes that the virulence of spirochetes is not strictly related to intestinal mucosal invasion.