Malacoplakia of the skin: overview of a rare clinical entity.

BACKGROUND: Malacoplakia is a rare acquired, infection-related granulomatous disorder, that may affect many systems, but typically occurs in the urinary tract. Cutaneous involvement is less prevalent, and most commonly presents with a perianal or genital region localization. Cutaneous malacoplakia is believed to be caused by an acquired bactericidal defect of macrophages in the setting of chronic infections and immunocompromised states. A diagnosis of cutaneous malacoplakia should be considered when encountering non-specific granulomatous lesions that are refractory to treatment. Histologic findings are marked by the presence of foamy macrophages containing the pathognomonic Michaelis-Gutman bodies. OBJECTIVES: The aim of this review is to discuss the current perspectives on the pathophysiology, clinical features, diagnosis, and treatment of this disease. We would also like to emphasize that the integration of clinical information, microscopic findings, and exclusion of other cutaneous granulomatous processes is necessary to accurately diagnose this exceedingly rare disease and provide opportunity for therapeutic intervention. PATIENTS/METHODS: Data for this work were collected from the published literature and textbooks. RESULTS: Combined surgical excision and protracted antibiotic courses appear to have the highest success rate. Antibiotics should be culture specific, but drugs that easily permeate the macrophages appear to be the best choice.

Malakoplakia in Thoracic Transplant Recipients.

Malakoplakia is a rare granulomatous disease characterized by the presence of Michaelis-Gutmann bodies on histopathologic analysis. Lesions manifest in a wide range of organs with cutaneous, gastrointestinal, and genitourinary systems being most common, and often result in significant comorbidities owing largely to misdiagnoses and the similar appearance to malignancy or granulomatous processes. Most patients are immunocompromised, including the solid-organ transplant population. Among organ recipients, malakoplakia is most commonly seen in renal transplantation, and only rarely reported in thoracic organ recipients. Herein we report 2 cases of malakoplakia in thoracic transplant patients that highlight the critical need for tissue diagnosis to avoid delay in management.

Malakoplakia of the thyroid gland: a case report and review of literature.

Malakoplakia is a rare granulomatous disease that most commonly occurs in the urinary tract. It is characterized by sheets of histiocytes with granular basophilic inclusions and Michaelis-Gutmann bodies. We present an exceedingly rare case of malakoplakia of the thyroid in a 54-year-old Caucasian woman on immunosuppressive therapy for renal transplant performed in 1994.

Detection of the 20-kDa virulence-associated antigen of Rhodococcus equi in malakoplakia-like lesion in pleural tissue obtained from an AIDS patient.

A malakoplakia-like lesion was detected in a pleural biopsy from an AIDS patient presenting clinical and radiologic features of pneumonia. Cultures of bronchoalveolar lavage and pleural fluid evidenced Rhodococcus equi as the causative agent of pleuro-pulmonary infection. Immunochemical characterization of the R. equi isolate showed the presence of a strain similar to the ATCC 33704 reference strain presenting the capsular antigen of serotype 4, and the intermediate virulence-associated antigen of 20-kDa. Histopathology of the patient's pleural biopsy showed plaques of macrophages interspersed with lymphocytes, and intracytoplasmic cocci and bacilli in macrophages, which were variably acid-fast positive. Immunohistochemistry of cocci, bacilli and their degradation products resulted strongly positive when stained with a mouse monoclonal antibody (MAb) produced against the 20-kDa antigen. This finding could have important implications for the pathogenicity of R. equi for human beings, since we do not know yet all the factors involved in the formation of malakoplakia. Indeed, the results obtained in the present study, taken together with the results obtained for pigs inoculated with R. equi strains of intermediate virulence (Madarame et al. 1998), raise the possibility that most strains presenting the 20-kDa antigen may be capable of inducing malakoplakia. If this hypothesis is confirmed by immunohistochemical analysis of human pulmonary malakoplakia cases due to R. equi, the detection of this antigen may be extremely helpful in the diagnosis and treatment of such patients. This is the first report of R. equi infection in human beings that suggests a relationship between pleural malakoplakia and the virulence-associated antigen of 20-kDa.

Focal malakoplakia in chronic periapical periodontitis.

AIMS: Three cases of chronic periapical periodontitis including focal areas with malakoplakia changes are reported. METHODS AND RESULTS: These areas included both von Hansemann-type macrophages and periodic acid-Schiff-positive, iron- and calcium-containing concretions. Some concretions corresponded to spherules with a targetoid configuration, thus fitting the morphological criteria for classical Michaelis-Gutmann bodies. CONCLUSION: The vast majority of the cases of malakoplakia that have been reported in the literature corresponded to a characteristic, fairly homogeneous lesion, but a few instances of focal malakoplakia have been described in various chronic conditions. These considerations support the opinion that the local conditions for the production of Michaelis-Gutmann bodies may occur focally in diseases characterized by macrophage accumulation.

Cutaneous malakoplakia in pigs inoculated with Rhodococcus equi.

Cutaneous malakoplakia was observed in pigs inoculated intramuscularly with Rhodococcus equi strains of intermediate virulence. Macroscopically, the inoculation sites showed the indurated swelling of the skin. Histopathologically, abscess formation with histiocytic granulomatous reaction was observed. Many macrophages contained target or owl-eye shaped hematoxyphil intracytoplasmic inclusions or calcosherites (Michaelis-Gutmann bodies) of various sizes. The Michaelis-Gutmann bodies were also seen outside of the macrophages. Histochemically, most Michaelis-Gutmann bodies stained positively with the von Kossa silver method and periodic acid Schiff. Immunohistochemically, some of Michaelis-Gutmann bodies were stained by two rabbit polyclonal antibodies (rabbit anti-A5 serum and rabbit anti-ATCC 33701 serum) and a mouse monoclonal antibody (anti-20-kDa antigen monoclonal antibody). This is the first report of cutaneous malakoplakia in domestic animals, which also revealed the relationship between R. equi infection and malakoplakia immunohistochemically. This experimental swine model is useful to investigate the morphogenesis of Michaelis-Gutmann bodies in malakoplakia through chronological skin biopsies.

Cutaneous malacoplakia: a report of two cases and review of the literature.

Malacoplakia, an inflammatory disease characterized by accumulations of phagocytic macrophages, occurs primarily in immunocompromised individuals. Cutaneous involvement is rare. Two men, each with a renal allograft, had expanding nodules on the temple and perianal area (case 1) and perianal, inguinal, and scrotal skin (case 2). Lesions resolved after combined surgical and antibiotic therapy. Histopathologic examination showed dense infiltration with large phagocytic macrophages containing round, concentric, laminar Von Kossa stain-positive inclusion bodies. Histiocytes had positive results for CD 68, lysozyme, and alpha 1-antitrypsin. Electron microscopic examination demonstrated rare intracytoplasmic inclusion bodies with concentric electron-dense laminations of calcium (Michaelis-Gutmann bodies.) Cutaneous malacoplakia should be considered in the differential diagnosis of nodules or draining ulcers, particularly in immunocompromised patients. Because Michaelis-Gutmann bodies are difficult to identify, specimens should be evaluated for cutaneous malacoplakia by immunohistochemical or electron microscopic means.

Antigenicities of enteropathogenic Escherichia coli, lysozyme, and alpha-1-antichymotrypsin on macrophages of genitourinary malacoplakia.

Seven cases of genito-urinary malacoplakia were analyzed histologically, ultrastructurally and immunohistochemically in a comparison with two cases of xanthogranulomatous pyelonephritis. Immunohistochemically, von Hansemann cells and Michaelis-Guttmann bodies, both hallmarks for the diagnosis of malacoplakia, showed a common antigenicity for enteropathogenic Escherichia coli as cytoplasmic granules of varying sizes. These microscopic manifestations corresponded ultrastructurally to a series of phagolysosomal degradations of coliform bacilli. Serogroups against E. coli OK antigens, which were positive for malacoplakic cells, were not confined to a particular group. Macrophages of xanthogranulomatous pyelonephritis did not show the E. coli antigenicity. Antigenicity of lysozyme and alpha-1-antichymotrypsin on the von Hansemann cells was equivocal, but these enzymes were strongly positive on macrophages of xanthogranulomatous pyelonephritis. The macrophages of both malacoplakia and xanthogranulomatous pyelonephritis were positive for antihuman macrophage antibody. These results indicate that malacoplakia depends mainly on infection by a non-specific strain of enteropathogenic E. coli and may arise from defective digestive enzyme activity of infiltrating macrophages. Immunohistochemical analysis using antisera against E. coli OK antigens, lysozyme and alpha-1-antichymotrypsin was useful in identifying the prediagnostic stage of malacoplakia and in differentiating the lesion from xanthogranulomatous pyelonephritis.

Malacoplaquia intestinal en pediatría: A propósito de un caso y revisión de la literatura / Intestinal Malacoplaquia

Se inform del caso de un niño de 13 años de edad hospitalizado en el Instituto Nacional de Salud del Niño, que ingresó con edema generalizado, diarrea crónica y hematoquezia. La biopsia de intestino estableció el diagnóstico de Malacoplaquia. A pesar del tratamiento instaurado la evolución clínica fué tórpida. Se revisa la literatura médica principalmente la relacionada al grupo pediátrico

[Malacoplakia and renal transplantation. Report of a case of testicular malacoplakia]. / Malakoplakie et transplantation rénale. Rapport d'un cas de malakoplakie testiculaire.

The authors report a case of testicular malakoplakia in a renal transplant patient. They emphasise the predisposing role of immunosuppression which was particularly intense in this patient and they stress the risk of dissemination of the disease to the graft.

Malakoplakia and immunosuppressive therapy. Reversal of clinical and leukocyte abnormalities after withdrawal of prednisone and azathioprine.

Malakoplakia is a chronic granulomatous inflammatory disorder. It is suspected clinically by the presence of chronic infection and diagnosed by histologic examination of affected tissues. Studies of 4 patients with malakoplakia--2 renal transplant recipients, 1 patient with systemic lupus erythematosus, and 1 patient with polymyositis--are reported. All patients were receiving prednisone and azathioprine at the time of diagnosis and had an infection caused by Escherichia coli. Leukocytes from all patients failed to kill Staphylococcus aureus and E coli normally in vitro. Cholinergic agonists had no apparent effect on bacterial killing in vitro or in vivo in the 2 patients examined. Clinically, malakoplakia improved significantly when immunosuppressive therapy was tapered or discontinued, and leukocyte function returned to normal in all 4 patients. The cases reported here and those documented previously suggest that the pathogenesis of malakoplakia and its treatment may not be the same for all patients. Malakoplakia may be more common than previously thought, particularly with the increased use of immunosuppressive therapy.

[Malakoplakia]. / La malakoplakie.

Malakoplakia is a fairly rare disease, normally found in women (four out of every five cases). It mainly attacks the urinary system, but may spread to the other viscera. The symptoms are not clinically specific. The main interest of the disease is its pathogenesis, from which its treatment is derived. It is in fact an immunological dysfunction of the phagocytes, leading to chemical disorders in the macrophages. Its treatment is based on the use of cholinergic agonists and vitamin C therapy.