Renal malakoplakia mimicking a malignancy and diagnosed by fine-needle aspiration: A case report

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.

Prostatic Malakoplakia: Clinicopathologic Assessment of a Multi-institutional Series of 49 Patients

Prostatic MP is rare, with only case reports and small series (<5 patients) available in the literature. In this study we analyzed an international multi-institutional series of 49 patients with prostatic MP to better define its clinicopathologic features. The median age was 67 years, and the median serum PSA was 7.5 ng/mL. MP was clinically manifest in most cases (28/45 patients with data available, 62%). Of 43 patients with detailed clinical history available, 21 (49%) had concurrent or metachronous malignancies (including prostate cancer). Diabetes or insulin resistance was present in 11 patients (26%). Additionally, 3 patients had a history of solid organ transplantation and 1 had HIV. Of note, 6/34 patients (18%) without concurrent prostate cancer had an abnormal digital rectal examination or PIRADS ≥ 4 lesions on MRI. The initial diagnosis was made on core biopsies (25/49, 51%), transurethral resection specimens (12/49, 24%), radical prostatectomies (10/49, 20%), Holmium-laser enucleation (1/49, 2%) and cystoprostatectomy (1/49, 2%). Tissue involvement was more commonly diffuse or multifocal (40/49, 82%). Von Kossa and Periodic acid-Schiff stains were positive in 35/38 (92%) and 26/27 lesions (96%), respectively. Of note, 2 cases were received in consultation by the authors with a preliminary diagnosis of mesenchymal tumor/tumor of the specialized prostatic stroma. In conclusion, the present study, which is the largest to date, suggests that prostatic MP often manifests with signs and symptoms that may mimic those of prostate cancer in a subset of patients. Moreover, MP may be found incidentally in patients with concurrent prostate cancer.