Renal parenchymal malacoplakia: a rare cause of ARF with a review of recent literature

A very complicated UTI: malakoplakia following E. coli urinary tract infection

Malakoplakia is a rare inflammatory disorder believed to result from a defect in macrophage phagocytic function triggering a granulomatous reaction. It can present with genitourinary, gastrointestinal, or cutaneous manifestations in immunocompromised or, less commonly, immunocompetent hosts. We describe a case of renal malakoplakia in a young, otherwise healthy patient presenting with nephromegaly and sepsis following an E. coli urinary tract infection. We discuss diagnosis and management, including antibiotic selection and the decision to pursue nephrectomy. This case highlights the potential for kidney recovery with prolonged antibiotic therapy in conjunction with adjunct immunomodulatory therapies and source control.

Multimodal imaging appearance including cinematic rendering of renal malakoplakia in a patient with E. coli bacteremia

Renal malakoplakia is a rare inflammatory disorder that predominantly affects the bladder, but has also been known to affect the kidneys. We present a case of a young woman with renal malakoplakia and concomitant E. coli bacteremia. The patient underwent numerous imaging studies during her clinical evaluation including ultrasound, magnetic resonance imaging, and computed tomography with 3-dimensional and cinematic renderings. Diagnosis was ultimately confirmed with renal biopsy which demonstrated Michaelis-Gutman bodies, a pathognomonic pathological finding in malakoplakia. She was started on antibiotics as well as bethanechol and ascorbic acid. Although her renal function improved with this treatment, she continued to have signs and symptoms of infection and she is planned for upcoming left nephrectomy.

Outgrowing skin involvement in malakoplakia after kidney transplantation: A case report

INTRODUCTION

Malakoplakia is a rare pseudotumor that arises in the context of recurrent infections, particularly in immunocompromised states. We report a case of renal allograft parenchymal malakoplakia.

CASE REPORT

A 59-year-old woman successfully received a cadaveric renal transplant in June 2018. Two months after transplantation, she was treated for a urinary tract infection (UTI). In March 2019, she underwent allograft biopsy for increasing creatinine. The biopsy identified T cell mediated rejection and steroid pulse therapy was performed. In December 2019, she was hospitalized for right flank pain and pyuria, and her creatinine level was 1.9 mg/dL. Radiographic findings were suggestive of a hematoma or abscess in the perirenal area, and septated fluid collection was suspected. Biopsy results suggested malakoplakia, and von Kossa stain was positive for Michaelis- Gutmann bodies. Tissue culture demonstrated Escherichia coli, and this was treated with antibiotics. The dose of tacrolimus was reduced. The patient was discharged after 1 month of hospitalization and was maintained on oral antibiotics. Follow-up imaging revealed an increase in the extent of lesion into the adjacent abdominal wall. Assuming the case to be refractory, we performed surgical resection and abscess drainage. Although the renal parenchymal involvement persisted, the size showed a decreasing trend over 2 months of serial observation with ultrasonography.

CONCLUSIONS

Malakoplakia should be considered as a differential diagnosis for recurrent UTI with graft dysfunction. Malakoplakia can be successfully treated with reduction in immunosuppression and medical therapy using long-term antibiotic treatment in most cases. However, early surgical treatment must be considered for refractory cases.

[Basic nephropathology for pathologists-part 1 : Kidney biopsy-inflammation and immune complexes]

The assessment of kidney biopsies is mainly confined to specialized centres. However, sometimes a kidney biopsy is submitted to a general pathologist, and in addition peritumorous renal parenchyma in tumour nephrectomies can have concomitant non-neoplastic renal disease. Here we present a survey of inflammatory and immunologic changes in all renal compartments, which may in part indicate the need of prompt therapeutic intervention such as in vasculitis, glomerulonephritis and interstitial nephritis. It is important to take into account that renal involvement of vasculitis is mainly centred in glomeruli and only to a much lesser extent in arteries, and that the frequently observed interstitial inflammation very often is an epiphenomenon of another primary kidney disease and not an independent disease process. Typical renal patterns of injury are emphasised.

CT and pathological features in renal parenchymal malakoplakia: a case report and review of the literature

Renal malakoplakia is a rare form of chronic inflammatory granulomatous disease in the kidney. It occurs in adult patients with immunocompromised status or debilitating disease. In the present study, we reported a case of a 50-year-old woman with no underlying disease. This report describes the CT and pathological features of renal malakoplakia in a 50-year-old woman. Plain CT scan showed a large soft tissue mass at the middle and upper pole of the left kidney. Enhanced CT scan showed delayed enhancement in the solid part of the mass. Our results might provide some useful information for the diagnosis of renal parenchymal malakoplakia.

Imaging Manifestations of Acute and Chronic Renal Infection That Mimics Malignancy: How to Make the Diagnosis Using Computed Tomography and Magnetic Resonance Imaging

PURPOSE

To review the computed tomography and magnetic resonance imaging manifestations of acute and chronic renal infections that may mimic malignancy and to provide useful tips to establish an imaging diagnosis.

CONCLUSION

Acute and chronic bacterial pyelonephritis are usually readily diagnosed clinically and on imaging when the diagnosis is suspected based upon clinical presentation. When unsuspected, focal, extensive or mass-like, acute and chronic bacterial pyelonephritis may mimic infiltrative tumours such as urothelial cell carcinoma (UCC), lymphoma, and metastatic disease. Infection may be suspected when patients are young and otherwise healthy when there is marked associated perinephric changes and in the absence of metastatic adenopathy or disease elsewhere in the abdomen and pelvis. Renal abscesses, from bacterial or atypical microbial agents, can appear as complex cystic renal masses mimicking cystic renal cell carcinoma. Associated inflammatory changes in and around the kidney and local invasion favour infection. Emphysematous pyelonephritis can mimic necrotic or fistulizing tumour; however, infection is more likely and should always be considered first. Xanthogranulomatous pyelonephritis can mimic malignancy when focal or multifocal and in cases without associated renal calculi. Malacoplakia is an inflammatory process that may mimic malignancy and should be considered in patients with chronic infection. Bacillus Calmette-Guerin (BCG)-induced pyelonephritis is rare but can mimic renal malignancy and should be considered in patients presenting with a renal mass when being treated with BCG for urinary bladder UCC.

Malakoplakia as a cause of severe hypercalcemia through ectopic 25-hydroxyvitamin D3 1-alpha-hydroxylase expression: A case report

RATIONALE

Malakoplakia is a rare disease characterized by the presence of nongranulomatous macrophage infiltration. In most cases, it affects the urinary tract. Malakoplakia can cause acute kidney injury when it is localized in the kidneys.

PATIENT CONCERNS

Here, we report the case of a 65-year-old female patient with renal malakoplakia responsible for hypercalcemia. During her initial assessment, she was also diagnosed 25-OH vitamin D insufficiency, for which she was prescribed oral cholecalciferol. Three months later, she developed severe hypercalcemia with normal 25-OH vitamin D and parathyroid hormone levels and high 1,25-dihydroxyvitamin D levels.

DIAGNOSES

After a superimposed granulomatous disease was excluded, malakoplakia cells were suspected to be responsible for the abnormal 25-hydroxyvitamin D3 1-alpha-hydroxylase activity, which was confirmed by immunohistochemistry.

INTERVENTIONS

Cholecalciferol was stopped, the patient was rehydrated with intravenous physiological saline, and prednisone was initiated to decrease the enzyme activity.

OUTCOMES

Six months later, she displayed normal serum calcium, 25-OH vitamin D and 1,25-dihydroxyvitamin D levels.

LESSONS

This case illustrates that malakoplakia may exhibit ectopic 25-hydroxyvitamin D3 1-alpha-hydroxylase activity and cause severe hypercalcemia upon vitamin D supplementation. Therefore, such supplementation should not be given in malakoplakia patients without an actual deficiency and requires careful monitoring of serum calcium.

[A Case of Xanthogranulomatous Inflammation of Terminal Ileum Presenting as a Mass in a Woman with Severe Obesity]

Xanthogranulomatous inflammation is an acute or chronic inflammatory condition most frequently reported in pyelonephritis and cholecystitis. However, the involvement of the terminal ileum is extremely rare. Its clinical significance is that it can m imic a malignant lesion clinically and intraoperatively, as well as radiographically. A 34-year-old European ethnic female presented with gradually aggravated abdominal pain in right lower quadrant for 15 days. There was no significant medical, surgical or traumatic history, except class III obesity (BMI, 41.0 kg/m ² ). An abdominal CT showed about a 4.7×3.7 cm sized, mass-like lesion in the terminal ileum. Despite symp tomatic treatment, her clinical symptoms did not improve. After six days, she underwent a laparoscopic ileocecectomy. Pathologic findings showed extensive inflammation with occasional multinucleated giant cells and aggregates of foamy histiocytes, consistent with xanthogran ulomatous inflammation. Here, we present a case of xanthogranu-lomatous inflammation in the terminal ileum presenting as subacute abdominal pain and a mass on imaging study. Xanthogranulomatous inflammation should be added to the differential diagnosis of patients with a suspected mass-like lesion in the terminal ileum.

Megalocytic interstitial nephritis following acute pyelonephritis with Escherichia coli bacteremia: a case report

Megalocytic interstitial nephritis is a rare form of kidney disease caused by chronic inflammation. We report a case of megalocytic interstitial nephritis occurring in a 45-yrold woman who presented with oliguric acute kidney injury and acute pyelonephritis accompanied by Escherichia coli bacteremia. Her renal function was not recovered despite adequate duration of susceptible antibiotic treatment, accompanied by negative conversion of bacteremia and bacteriuria. Kidney biopsy revealed an infiltration of numerous histiocytes without Michaelis-Gutmann bodies. The patient's renal function was markedly improved after short-term treatment with high-dose steroid.

Autopsy Renal Pathology

We provide an overview of assessment of the kidneys at autopsy, with special considerations for pediatric versus adult kidneys. We describe the approach to gross examination, tissue allocation when needed for additional studies of potential medical renal disease, the spectrum of congenital abnormalities of the kidneys and urinary tract, and approach to cystic diseases of the kidney. We also discuss common lesions seen at autopsy, including acute tubular injury, ischemic versus toxic contributions to this injury, interstitial nephritis, and common vascular diseases. Infections commonly involve the kidney at autopsy, and the key features and differential diagnoses are also discussed.

[Case of renal parenchymal malakoplakia presenting as sepsis and treated with nephrectomy]

Malakoplakia is a rare chronic inflammatory condition characterized by defective macrophage function, most of which involve the genitourinary tract, and renal parenchymal involvement is uncommon. We present a case of malakoplakia affecting renal parenchyma. A 46-year-old woman with pyrexia and jaundice was referred to our department. Abdominal enhanced CT scan revealed a left pyelonephritis with ureteral stone and bilateral renal abscesses. Despite the insertion of a left ureteral stent and administration of antibiotics, the patient showed persistent high fever and elevated CRP, and no obvious improvement in clinical and imaging data. In view of the limited effectiveness of the conservative treatment in this case, we decided to perform left nephrectomy. The diagnosis of malakoplakia was made based on the histopathological findings of von Hansemann cells and Michaelis-Guttmann bodies detected in the nephrectomy specimen. She is clinically healthy up to the present (50 months after surgery) with normal clinical indicators and CT findings.

Renal malakoplakia as a pseudotumoral lesion in a renal transplant patient: a case report

Malakoplakia is a rare chronic inflammatory disease associated with gram-negative bacterial infections frequently caused by Escherichia coli. Malakoplakia usually affects the lower urinary tract (bladder) but there are cases described in the kidney as well as in the respiratory and digestive organs. We report on a case with renal parenchymal malakoplakia in a renal transplant patient and describe the pathological lesions of malakoplakia: histiocytic proliferation with scarce inflammatory infiltrate, histiocytes with acidophilic cytoplasm and the presence of characteristic Michaelis-Gutmann bodies. The authors in this study review the updated reports related to the entity in this uncommon localization, the association with an immunocompromised patient, the macroscopic presentation as a pseudotumoral lesion and the possible relationship with the xanthogranulomatous pyelonephritis as a form of a histopathological spectrum in patients affected with gram negative urinary tract infection.

[Malakoplakia in urology: six cases report and review of the literature]

Malakoplakia (MLP) is a rare chronic granulomatous disease that is believed to happen because of an alteration in the bacterial phagocytic system. This entity is characterized by one or multiple tumorations that can appear in any part of the body leading to it's misdiagnosing as a malignant condition. The genitourinary tract is frequently involved. Pathologic study of these lesions shows tissue infiltrated by inflammatory cells (macrophages and hystiocites) with intracytoplasmatic inclusions, which are known as Michaelis-Gutmann bodies. Usually is a benign condition self-limited and is associated with recurrent urinary tract infection (UTI), this condition has a good response to prolonged treatment with fluoroquinolones. We will report six cases that were diagnosed and treatment in our institution during an eight year period. We report still a review of the available literature.