Successful use of azithromycin for Escherichia coli-associated renal allograft malakoplakia: a report of two cases.

Malakoplakia is a chronic granulomatous disease associated with incomplete clearance of bacterial pathogens. A multimodal approach to therapy includes antimicrobials with intracellular activity, reduction in immunosuppression, and debulking of lesions. Azithromycin has an intracellular mechanism of action and enhanced Gram-negative activity compared to other macrolides. Despite some in vitro data to support its use, there are no clinical breakpoints or epidemiological cut-off values for most Enterobacterales from the European Committee on Antimicrobial Susceptibility Testing (EUCAST) or the Clinical and Laboratory Standards Institute (CLSI). We present two cases, previously unreported, of Escherichia coli associated renal allograft malakoplakia successfully treated with azithromycin.

Ultrastructural evidence of the evolutional process in malakoplakia.

CONTEXT: Malakoplakia can be caused by incomplete digestion of Escherichia coli by lysosomes, leading to recurrent urinary tract infections and consequential mass-forming events that mimic tumors. OBJECTIVES: By using ultrastructural findings, we aimed to specify the process of phagolysosome to evoke malakoplakia. DESIGN: We observed a series of processes to form a peculiar Michaelis-Gutmann (MG) body in three patients with malakoplakia and compared with xanthogranulomatous pyelonephritis. RESULTS: The ultrastructural findings were realigned according to the sequence of events as pre-phagosomal, phagosomal, and post-phagosomal stages. For the mature MG body, numerous lysosomal aggregates targeting pathogens and subsequent incomplete digestion are prerequisite factors for the pre-phagosomal stage. Scattered lamellated residue is late evidence of the pre-phagosomal stage. Phagosomes can be formed by the fusion of multiple pathogens and multiple lysosomes. We utilized transmission and scanning electron microscopy to speculate on the process of phagolysosomal formation. CONCLUSION: The recognition of E. coli captured by phagosomes or partially damaged by lysosomal attack within the cell was recorded for the first time. Furthermore, SEM observation was performed on human tissue.

[Malakoplakia of the submandibular gland in a renal transplant patient]. / Malakoplakie de la glande sous-mandibulaire chez un patient transplanté rénal.

INTRODUCTION: Malakoplakia (MP) is a rare granulomatous disease, usually occurring in immunocompromised patients, linked to Escherichia coli infection. The lesions are usually located in the genitourinary tract, but there is a great variability in the topography and the clinical presentation. CASE REPORT: A 70-year-old diabetic kidney transplant patient under immunosuppressive treatment presented with a voluminous submandibular chronic lesion, involving the skin, associated with a burgeoning lesion of the oral mucosa. Histological examination of biopsies concluded to MP and bacteriological samples were positive for E. coli. Antibiotic treatment allowed for the regression of the lesion before surgical removal. Histological examination of resected material confirmed the diagnosis of invasive MP of the submandibular gland. DISCUSSION: The diagnosis of MP relies on histological examination, showing the presence of von Hansemann's cells and Michaelis- Gutmann bodies. The treatment is based on active antibiotics targeted against intracellular bacteria, possibly associated with surgery. We report the first case of MP involving the submandibular gland.

Malakoplakia of liver: report of two cases.

Malakoplakia is an unusual chronic inflammatory condition characterized by the presence of Michaelis-Gutmann bodies. Patients with malakoplakia often have an immunodeficiency state. It is believed that malakoplakia results from a defective macrophage response to phagocytosed bacteria. Malakoplakia most commonly affects the genitourinary tract. Cases confined to the liver are rare, with only five cases described in the literature. We report two cases of malakoplakia of liver; both were incidental autopsy findings. The first case involves a 53-year-old man with systemic lupus erythematosus and chronic refractory pancytopenia who presented with febrile neutropenia. His blood culture was positive for Stenotrophomonas maltophilia and Enterococcus faecium, and he subsequently developed invasive pulmonary aspergillosis. The second case involves a 60-year-old man who presented with a mass in periorbital tissue which, on biopsy, showed inflammation and Treponema-like spirochetes. He died unexpectedly at home. Autopsy revealed adrenal gland chronic inflammation and abscess. Both cases had grossly normal livers with microscopic findings of calcified targetoid structures consistent with Michaelis-Gutmann bodies. In these cases, malakoplakia was an incidental finding confined to liver. Although asymptomatic in these cases, diagnosis in the liver may be useful to initiate a search for hepatic or non-hepatic infections.

Pulmonary malacoplakia at early stage: use of polymerase chain reaction for detection of Rhodococcus equi.

Malacoplakia is a rare inflammatory condition characterized by the accumulation of benign macrophages associated with pathognomonic Michaelis-Gutmann bodies (MGBs). It is usually found in the genito-urinary tract, and has been associated with immunocompromised states. In this short report, we present 5 patients with pulmonary nodules clinically suspicious for primary or metastatic lung cancer. The histologic examination of the surgical specimens revealed a nonspecific granulomatous chronic disease, and despite the paucity of classical MGBs, a pulmonary malacoplakia was suspected. In all cases the opportunistic pathogen Rhodococcus equi (R. equi) was identified by 16S rRNA gene sequence analysis, leading to the final pathological diagnosis of malacoplakia. We conclude that pulmonary malacoplakia associated with R. equi is a rare disease affecting also immunocompetent patients. The pathogenesis and the diagnostic problems are discussed. Since infection by R. equi is treatable, the importance of its early recognition should be emphasized.

Pleural malakoplakia caused by Rhodococcus equi infection in a patient after stem cell transplantation.

Malakoplakia is a disease especially of the urinary tract with typical plaques most frequently observed in the urinary bladder's mucosa. In the context of immunosuppression malakoplakia can also occur in other organs. Some of these extravesical malakoplakias are associated with an infection by Rhodococcus equi, a rare human pathogen well known from veterinary medicine. Here we present the first case of a pleural malakoplakia without lung involvement caused by a proved Rhodococcus equi infection.

Pseudotumor of the tracheal-laryngeal junction with unusual morphologic features caused by Rhodococcus equi infection.

Infectious pseudotumors are unusual proliferations of histiocytes in response to certain microbial organisms. Occasionally this process may involve large airways, producing a mass lesion that may cause respiratory obstruction. Infectious pseudotumors can be confused with malignancy in their radiologic appearance and clinical presentation. We present a case of an aggressive endotracheal pseudotumor associated with Rhodococcus equi infection in a patient with advanced HIV disease. Microscopically, the lesion was composed of sheets of epithelioid histiocytes with large, strongly eosinophilic intra-cytoplasmic granules and features of malakoplakia. In this report, we review the literature of these unusual lesions and compare them to cases of conventional malakoplakia involving the large airways. We also explore the pathogenetic mechanisms that may contribute to the distinctive histologic appearance of Rhodococcus-associated pseudotumors.

[Colonic malacoplakia treated with sulfamethizole and trimethoprim]. / Malokoplaki i colon behandlet med sulfamethizol og trimetoprim.

We report a case of colonic malacoplakia in a 78-year-old woman, developed following short-term treatment with prednisolone. Clinically, the patient presented with diarrhoea (up to ten times a day) and malaise. Laboratory tests revealed severe anaemia and elevated inflammatory parameters. Colonoscopy showed macroscopic yellowish nodular changes throughout the colon. Biopsies were diagnostic for malacoplakia and exhibited moderate growth of Escherichia faecium and ciprofloxacin-resistant Escherichia coli. The condition resolved during three months of antibiotic treatment with sulfamethizole and trimethoprim.

Extragenitourinary malakoplakia in a patient with myeloma clinically mimicking extramedullary myelomatous disease.

Malakoplakia is a rare granulomatous disorder of unknown etiology and usually affects patients with underlying immunosuppression. This disorder usually involves the genitourinary tract but has been reported in a wide array of anatomical sites. We present a case of extragenitourinary malakoplakia, developing in a patient with a history of plasma cell myeloma, which clinically mimicked recurrent extramedullary myelomatous involvement. Radiologically, this lesion was a 10-cm soft-tissue mass located in the left flank and iliacus muscle. Excisional biopsy revealed a histiocytic infiltrate with histologic features diagnostic of malakoplakia. This case demonstrates the clinical and pathologic diagnostic challenges of malakoplakia arising outside the genitourinary tract. Given that it can closely mimic malignancy in such settings, malakoplakia should be considered in the differential diagnosis of soft-tissue masses developing in patients with hematologic malignancy and iatrogenic immunosuppression. This case highlights the importance for awareness on the part of clinicians, radiologists, and pathologists that malakoplakia can present as a soft-tissue mass.

Cutaneous malakoplakia in an HIV-positive patient.

Malakoplakia is an uncommon granulomatous infectious disease that is found primarily in the genitourinary tract, but may rarely involve the skin. We report a case of cutaneous malakoplakia in an HIV-positive patient diagnosed on the basis of Michaelis-Gutman bodies. The patient presented with ulcers, draining sinuses and tender papules and nodules mainly on perigenital area, buttocks and right thigh.

Ultrasonographic evaluation of renal infections.

Renal sonography can be easily performed and provides valuable information concerning the underlying disease process, helping to decide appropriate management. This article reviews the important renal infections, such as pyelonephritis, emphysematous pyelonephritis, renal abscess, hydatid disease, renal tuberculosis, pyonephrosis, and HIV-associated nephropathy.

[A rare case of birenal malacoplakia with renal failure]. / Seltener Fall einer birenalen Malakoplakie mit Nierenversagen.

HISTORY AND ADMISSION FINDINGS: A 45 year old man was admitted to our hospital because of fever, loss of appetite, and deterioration of general health. For two weeks the patient suffered from diarrhea which had resulted in moderate volume depletion. In addition, he complained of bilateral flank pain at the time of admission. Furthermore, the patient had a history of heavily drinking alcohol as well as cigarette smoking for many years. He had never attended a medical doctor before. INVESTIGATIONS: The patient presented with the clinical picture of acute renal failure and urosepticaemia which was caused by Escherichia coli. The kidneys were found to be at the upper limit of normal by sonography. Magnetic resonance imaging revealed signal-alterations in both kidneys with hyper- and hypointense zones in the renal parenchyma. DIAGNOSIS: To clarify the cause of rapid deterioration of renal function, we performed a renal biopsy. The histology of the renal specimen revealed an unusual type acute bacterial interstitial nephritis most likely due to an infection with E. coli. The clinical picture, the laboratory findings and renal histology, lead to the diagnosis of birenal malakoplakia. TREATMENT AND COURSE: After intravenous and subsequent oral antibiotic therapy the fever and the clinical signs of urosepticaemia subsided and renal function gradually improved. Antibiotic therapy and supplementation with vitamins were continued for 20 weeks. Five years after initial diagnosis, renal function was stable at a glomerular filtration rate of approximately 45 ml/min. CONCLUSIONS: Malakoplakia of the kidney is a rare form of bacterial interstitial nephritis and requires long-term antibiotic therapy.