Malacoplakia Presenting as a Solitary Renal Mass

Abstract

1703alacoplakia, a rare granulomatous inflammatory disease characterized by pathognomonic intracytoplasmic Michaelis-Gutmann bodies, was first reported as a lesion of the urinary bladder in 1902. Until the 1950s, this disease was thought to occur exclusively in the urinary tract. Malacoplakia, however, affects many other organ systems including the gastrointestinal tract, bone, lungs, lymph nodes, and skin. The urinary tract is most frequently involved, and all parts of the urinary tract can be affected. In a 1981 review of 153 cases, 89 (58%) had involvement of the urinary tract and 63 (40%) had bladder lesions. The next most common site was the kidney (16%) [1]. Sixty-two cases of renal involvement were found in a review published in 1993 [2]. Renal lesions are most often multifocal and frequently involve both kidneys. We report a case of malacoplakia in a 37-year-old man who presented with a complicated cystic renal lesion that increased in size over the 2 years that he was monitored using CT. Case ReportA 37-year-old man with no significant medical history was referred for evaluation of an enlarging cystic renal mass that had been followed for 2 years using CT. The patient initially presented for treatment of acute bacterial prostatitis, which subsequently resolved with antibiotic therapy. An initial CT study of the abdomen, performed for evaluation of persistent microscopic hematuria after this episode, showed a 2-cm, predominantly low-attenuation lesion with a septum located in the upper pole of the left kidney (Figs. 1A and 1B). On CT 2 years later, the lesion had increased in size and measured 2.8 cm in diameter. The lesion was heterogeneous with an attenuation of 27 H (Figs. 1C and 1D). Because unenhanced images were not obtained for either study, enhancement could not be determined. Because this lesion not only was a complicated cystic lesion but had enlarged in the interval, the patient underwent laparoscopic radical nephrectomy, which was performed without complication. Subsequent CT and sonography of the abdomen and urine cultures have remained normal at 1-year follow-up.On gross examination, the lesion was multiloculated; measured 2.5 × 1.2 × 1.2 cm; had a smooth, thickened inner lining; and contained grossly hemorrhagic fluid. Microscopic examination of the renal parenchyma and calices showed well-delineated aggregates of histiocytes with intracellular round, concentric, laminar, Michaelis-Gutmann bodies positive for anions of calcium salts using von Kossa's stain. No microorganisms were present. DiscussionMalacoplakia is a rare granulomatous inflammatory process that affects many organ systems including the genitourinary tract, gastrointestinal tract, bone, lungs, lymph nodes, and skin. Aside from the urinary tract, no sex predominance is seen. The genitourinary tract is affected most often, particularly in immunocompromised individuals. Disease of the genitourinary system is most common in middle-aged women (female-male ratio, 4:1), with an average age at presentation of more than 50 years [1]. M...

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

“…The electron microscopy showed phagolysosomes in different stages and bacterial rests included in the histiocytes. 2,5,7 We report this case because of the unusual form of malakoplakia presentation as a pseudotumoral lesion. 2 A percutaneous needle biopsy was not performed because the general clinical conditions of the patient ameliorated and the clinician decided to carry out a nephrectomy.…”

“…2,5,7 We report this case because of the unusual form of malakoplakia presentation as a pseudotumoral lesion. 2 A percutaneous needle biopsy was not performed because the general clinical conditions of the patient ameliorated and the clinician decided to carry out a nephrectomy. If the The differential diagnosis of malakoplakia includes other chronic inflammatory processes such as Mycobacterium avium infection; renal fungus infection and renal neoplasm as renal cell carcinoma; squamous cell carcinoma; and renal non-Hodgkin Lymphomas in transplanted and/or immunocompromised patients.…”

“…2 In immunocompromised patients, the differential diagnosis with non-Hodgkin lymphoma is very important because the therapy and prognosis are different.…”

Malakoplakia of the Urinary Tract: A Benign Disease with a Possible Malignant Outcome

“…Wielenberg et al [11] in a review of 153 cases, found 89 cases (58%) that involved the urinary tract, out of which 63 (40%) occurred in the urinary bladder. Next to the bladder, commonly involved urinary sites are the kidneys, ureters, and renal pelvis.…”

Malakoplakia of Gall Bladder: A Histological Surprise

“…It is a form of chronic granulomatous disease, usually affecting urinary tract [4]. It can also affect the other parts of the body such as gastrointestinal, genital, and biliary tracts, central nervous system and skin.…”