Sclerosing mesenteritis due to Mycobacterium genavense infection: A case report

Abstract

Rationale: Since its first identification in the early 1990s, Mycobacterium genavense has been considered and opportunistic pathogen. It mainly causes gastrointestinal symptoms, but also disseminated infections in severely immunosuppressed patients. Sclerosing mesenteritis is a long-term complication with high morbidity and mortality. As it is a rare condition, there are no specific guidelines for its management. We report a challenging case of persistent M. genavense infection, and propose surgery as an alternative treatment strategy.

Patient concerns: A 38-year-old Caucasian man presented to the emergency room with fever, abdominal pain, and night sweats for 3 months. HIV screening revealed a previously unknown HIV-1 infection, with a CD4 cell count of 216 cell/µL and viral load of 361.000 copies/mL at diagnosis. A body CT-scan showed mild splenomegaly as well as mesenteric and retroperitoneal enlarged lymph nodes. Fine needle aspiration revealed the presence of acid-fast bacilli, but mycobacterial cultures were negative. In the second sample, 16S RNA sequencing yielded a diagnosis of M. genavense infection. Despite 2 years of corticosteroids and antimycobacterial treatment excluding rifampicin due to a severe cutaneous reaction, there was no clinical improvement and an increase in the mesenteric lymph node size was observed, with a sclerosing transformation of the mesentery. A surgical approach was proposed to release small bowel loops and to remove fibrin. A second surgery was required due to an acute peritonitis ought to yeyunal segmental isquemia and perforation. Finally, the patient evolved favorably, and antimycobacterial drugs were suspended without relapse.

Lessons: Despite a prolonged multidrug strategy, some patients develop persistent M. genavense infection. Once sclerosing mesenteritis is established, clinicians have few treatment options. Surgery should be considered in patients with sclerosing mesenteritis or bowel obstruction. The combination of medical and surgical treatment could be a potential cure for these patients.

Figure 1.

Images of the CT-scan performed in February 2019. White arrows show mesenteric lymph node enlargement. Mild splenomegaly (14 cm) is also indicated.

Figure 2.

Images of the CT-scan performed in May 2021. White arrow shows mesenteric sclerosis.

Figure 3.

Intraoperative images showing retraction of the mesentery, fibrin and profuse inflammatory exudate.

Figure 4.

Images of the CT-scan performed in December 2021. It shows radiological improvement, without peritoneal abscesses nor mesenteric lymph node enlargement.