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Kidney Week

Abstract: SA-PO1118

Mystery Mass in an Asymptomatic Kidney Transplant Recipient

Session Information

Category: Trainee Case Report

  • 1902 Transplantation: Clinical

Authors

  • Kochar, Guneet S., Vanderbilt University Medcial Center, Nashville, Tennessee, United States
  • Concepcion, Beatrice P., Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Satyanarayana, Gowri, Vanderbilt University Medical Center, Nashville, Tennessee, United States
Introduction

Malakoplakia is a rare inflammatory granulomatous mass comprised of partially digested bacteria due to the inability of macrophages to completely digest an infectious organism. It is most often seen in immunocompromised patients. Here we present a case of malakoplakia in a recent kidney transplant recipient with a complex urologic history who was otherwise asymptomatic.

Case Description

A 64-year-old male who received a living unrelated kidney transplant four months ago, complicated by slow graft function after transplant, and right femoral AV fistula ligation one month ago presents with two weeks of swelling in his right groin. He had bladder cancer with cystectomy and creation of an Indiana pouch with urinary diversion nineteen years ago, subsequent development of stomal stenosis and a ureteroenteric stricture causing obstructive nephropathy. The obstruction and chronic hypertension led to renal failure requiring hemodialysis. His creatinine improved after ligation of the right femoral AV fistula. Two “knots” in his right groin developed two weeks after fistula ligation and began draining purulent fluid. He admitted to intermittent cloudy urine draining from his urostomy but denied fevers, chills, allograft pain, weight loss, fatigue, malaise. A CT scan revealed a possible post-operative hematoma versus an indeterminate mass. Surgical exploration revealed scant seropurulent drainage, and organized inflammatory and necrotic tissue. Pathology was significant for PAS-diastase and iron stains with numerous intracytoplasmic targetoid inclusions, consistent with pathognomonic Michaelis-Gutmann bodies. Cultures were positive for E. coli. The patient was treated with 4 weeks of ceftriaxone with subsequent resolution of his groin swelling.

Discussion

While malakoplakia is a rare diagnosis, this should be considered in the differential of any immunosuppressed patient with a mass. Tissue diagnosis, to confirm with specific request for PAS and von Kassa staining allows for identification of the pathognomonic Michaelis-Guttmann bodies. Cultures identify a causative organism and allow for targeted treatment. Most commonly, E. coli is the underlying pathogen, but Klebsiella, Pseudomonas, Enterococcus, and Streptococcus have been identified. Finally, careful evaluation of the immunosuppressive regimen should be undertaken if malakoplakia is identified.