Abstract: TH-PO812
Renal Malakoplakia: A Rare Disease Causing Acute Renal Failure
Session Information
- Pathology and Lab Medicine - I
November 02, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pathology and Lab Medicine
- 1800 Pathology and Lab Medicine
Authors
- Ladiwala, Zoya, Luminis Health Anne Arundel Medical Center, Annapolis, Maryland, United States
- Adnani, Harsha, Luminis Health Anne Arundel Medical Center, Annapolis, Maryland, United States
Introduction
Malakoplakia is a rare chronic inflammatory condition characterized by granulomatous lesions, frequently involving the kidneys. We present a case of renal malakoplakia in the setting of Escherichia coli (E.coli) bacteremia leading to acute renal failure.
Case Description
A 36-year-old woman presented with vomiting and shortness of breath. Initial evaluation revealed hypotension, tachycardia, leukocytosis (22,000/μL), and acute kidney injury with elevated creatinine (6.4 mg/dL from a baseline of 0.6 mg/dL). Urinalysis showed blood, leukocytes, bacteria, and a urine protein/creatinine ratio of 31 mg/mg. Computed tomography scan indicated fatty hepatomegaly and globular nephromegaly. Urine and blood cultures grew E. coli. The patient was treated for septic shock with antibiotics and vasopressors. However, she developed oliguric acute renal failure and required continuous renal replacement therapy. A left kidney biopsy was pursued to evaluate the nephromegaly, which revealed multifocal microabscesses, parenchymal necrosis, fibrosis, calcifications, and an inflammatory infiltrate with histiocyte predominance, consistent with malakoplakia. Von Kossa stain confirmed the presence of numerous Michaelis-Gutmann bodies. Renal mercaptoacetyltriglycine 3 scan showed differential function of 25% in the left kidney and 75% in the right kidney. Despite prolonged antibiotic therapy, the patient continued to experience volume overload, persistent leukocytosis, bacteremia, and fungemia. Given the higher disease burden in the left kidney, she underwent a radical left nephrectomy for source control. Postoperatively, her clinical condition improved, and she was discharged on suppressive minocycline.
Discussion
The pathogenesis of malakoplakia involves impaired bactericidal capacity of macrophages. Michaelis-Gutmann bodies, characterized by calcium and iron deposits, are pathognomonic. Diagnosis is challenging due to variable clinical presentations and imaging findings resembling malignancy. Renal biopsy remains the gold standard for definitive diagnosis. Given its rarity, evidence-based treatment is limited; however, a general approach includes systemic antibiotics and surgical excision.
Renal malakoplakia poses clinical challenges in differentiating from other infections and tumors. Early diagnosis through biopsy is crucial for prompt treatment and to prevent long-term morbidity and mortality.