Histoplasmosis as a possible cause of retroperitoneal fibrosis and median arcuate ligament syndrome: A case report

INTRODUCTION: Median arcuate ligament syndrome (MALS), a condition of poorly understood etiology, is caused by compression of the celiac artery by fibers of the median arcuate ligament. PRESENTATION OF CASE: A 46-year-old man with chronic abdominal pain and weight loss was diagnosed with MALS and admitted for surgery. During surgery, extensive retroperitoneal fibrosis around the celiac artery and adjacent aorta was noted. Large necrotizing granulomas and budding yeast, both indicators of histoplasmosis, were found on pathologic evaluation of retroperitoneal tissue removed during surgery. DISCUSSION: Histoplasma capsulatum may cause pulmonary fibrosis and fibrosing mediastinitis, and the organism may disseminate to reach various internal organs in the immunocompromised individual. Retroperitoneal histoplasmosis has been demonstrated in immunocompromised individuals in the past without retroperitoneal fibrosis. Our patient may have had chronic histoplasma infection of his retroperitoneal lymph nodes, triggering fibrosis in the area surrounding the adjacent celiac artery and abdominal aorta, thus leading to symptomatic MALS. CONCLUSION: Histoplasma capsulatum, an organism that has demonstrated its capability to cause fibrosis elsewhere in the body, may play a causative role in MALS in our patient, given the finding of retroperitoneal fibrosis in conjunction with retroperitoneal lymph node histoplasma.