Malakoplakia is a rare, chronic granulomatous inflammatory condition predominantly affecting immunocompromised individuals. The condition most commonly involves the urogenital tract, but it can affect nearly every organ system in the body, including the pulmonary, gastrointestinal, endocrine, lymphatic, and musculoskeletal systems, the central nervous system (CNS), and the skin, and therefore poses a diagnostic challenge. Although the etiology is not completely understood, the most widely accepted theory is that the condition is due to defective phagolysosomal activity within macrophages, leading to an abnormal granulomatous reaction to the partially digested bacteria within these immune cells. Gram-negative bacteria are frequent culprit organisms (including Escherichia coli, Pseudomonas, Proteus, and Shigella spp.). Staphylococcus spp. have also been found to be causative in some cases.

Malakoplakia may occur at any age, but it classically affects middle-aged women. Children are rarely affected. Most cases reported occurred in immunocompromised patients, including those with malignancy, hypogammaglobulinemia, autoimmune disorders such as rheumatoid arthritis, or chronic conditions such as diabetes mellitus, HIV / AIDS, and post-organ transplantation, primarily kidney transplants. Malakoplakia has only rarely been reported in immunocompetent individuals.

Malakoplakia, from the Greek malako meaning "soft" and plako meaning "plaque," typically presents with soft, friable mucosal papules, plaques, or nodules that predominantly affect the genitourinary tract. Patients may be asymptomatic or present with pain and fever, with additional findings depending on the organ systems affected. Genitourinary tract involvement classically presents in a middle-aged woman with dysuria, recurrent urinary tract infections (UTIs), hematuria, and abdominal pain.

Cutaneous malakoplakia manifests in the perineal and genital regions as friable papules or nodules, abscesses, draining sinuses, or ulcers.