Malakoplakia in a Kidney Transplant Recipient

Introduction: Malakoplakia (MK) is a rare inflammatory condition of impaired phagocytosis, often linked to gram-negative infections. It can be devastating in kidney transplant recipients. Presentations vary, from renal dysfunction to extra-renal involvement. Case Description: A 57-year-old female with end-stage renal disease due to hypertensive nephrosclerosis underwent a kidney transplant five months prior, with recurrent urinary infections post-transplant. She presented with a 50-pound weight loss, three weeks of dysuria, weakness, and hematuria. Labs showed severe acute kidney injury, metabolic acidosis, and elevated lactate. Blood and urine cultures detected E. coli. Ultrasound revealed a hypoechoic focus in the graft, on CT an ill-defined mass suggestive of pyelonephritis or abscess. MRI showed fingerlike masses extending into the cortex, suspicious for post-transplant lymphoproliferative disorder or malignancy. Biopsy showed no malignancy, but identified Michaelis-Gutmann bodies (MGBs). Her immunosuppression was reduced, and long-term antibiotics started. She succumbed to septic shock complications three months later. Discussion: Malakoplakia is poorly understood due to its rarity. In renal transplant patients, urinary infections, graft dysfunction, or new masses should prompt consideration of MK. Its pathophysiology involves impaired phagocytosis, likely due to inadequate cyclic GMP release, hampering macrophage bactericidal activity and increasing infection risk. Pathognomonic biopsy findings include intracytoplasmic Periodic acid-Schiff positive inclusions (MGBs) and histiocytes with granular cytoplasm (von Hansemann cells). Management includes prolonged antibiotics, reduction of immunosuppression, and occasionally surgical excision. Despite this regimen improving mortality, morbidity remains high due to graft failure. Early recognition and timely biopsy are crucial to optimizing outcomes.MGBs on biopsy