Bilateral Renal Fungal Bezoars and Perinephric Abscess in an Infant With Arthrogryposis-Renal Dysfunction-Cholestasis Syndrome: A Clinico-pathologic Case Report.

The patients with Arthrogryposis-Renal dysfunction-Cholestasis (ARC) syndrome have genetic susceptibility to the opportunistic infections due to the involvement of VPS33B (vacuolar protein sorting 33 homolog B) in phagolysosome fusion in macrophages. Detailed pathologic studies in ARC patients are missing in literature due to the lack of autopsy. We described the first autopsy case of ARC syndrome in a 2-month-old male infant. His death was due to recurrent sepsis and multiorgan failure despite the appropriate poly-antibiotic therapy and supportive care. The autopsy showed invasive renal candidiasis including bilateral destructive pyelonephritis, pelvic obstructive fungal bezoars, and right large perinephric abscess. The main other findings included severe chronic liver changes and pneumonia. Liver exhibited intrahepatocyte cholestasis, large multinucleated hepatocytes, diffuse portal, bridging and perivenular fibrosis, and interlobular bile duct proliferation. The neuropathologic examination was unremarkable. This case report highlights 3 novel findings. The ARC syndrome-related immunodeficiency may predispose to renal fungal bezoars and perinephric abscess. Cholestatic stress may result in the proliferation of interlobular ducts as an adaptive response. Absence of spinal motor neuron degeneration suggests that the neurogenic amyotrophy is due to the lack of synaptic vesicle trafficking and membrane fusion rather than the defect in cell survival-related autophagosome-lysosome fusion.