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Malakoplakia is a rare chronic inflammatory condition, which primarily occurs in genitourinary tract, with prostatic malakoplakia being extremely rare. We present two cases of acute urinary retention, with clinically firm nodular prostate and a raised serum prostate-specific antigen. Transrectal ultrasound-guided prostatic biopsy showed features of malakoplakia. There was a significant reduction of size of prostate on transrectal ultrasonography after 4 weeks of antibiotics. However, one patient had failed trial without catheter and was subjected to transurethral resection of prostate. The biopsy of the prostatic chips also showed features of malakoplakia. Other patient improved symptomatically after antibiotics and was managed conservatively. Both the patients are on regular follow-up and are asymptomatic. Prostatic malakoplakia presenting as urinary retention is very uncommon with around 12 cases in the literature. Recognition of prostatic malakoplakia is important because clinically it can masquerade prostatic malignancy. Treatment with antibiotics is necessary before subjecting the patients for surgery in patients with obstructive symptoms.

Background Malakoplakia is an uncommon, tumor-like inflammatory disease characterized by impaired histiocytes that are unable to completely digest phagocytized bacteria. The genitourinary tract is the most common site of involvement, however, cases have also been described in the gastrointestinal tract, suggesting that it is the second most common site of involvement. This study investigates the clinical and histologic features of malakoplakia in the gastrointestinal tract. Case presentation For 23 gastrointestinal specimens (biopsies and resections) from patients with a pathologic diagnosis of malakoplakia, we recorded the gender, age, location, primary diagnosis, endoscopic or surgical indication, endoscopic/gross impression and immune status (immunocompromised vs. immunocompetent). Conclusion Malakoplakia occurred throughout the length of the gastrointestinal tract with most of the cases located in the sigmoid colon and rectum (n = 10); other sites included the transverse and descending colon (n = 4), stomach/gastroesophageal junction (n = 4), appendix (n = 2), cecum (n = 1), small bowel (n = 1), and the peri-anal area (n = 1). Endoscopically, these lesions most commonly appeared as polyps (n = 10) or masses (n = 5), other clinical endoscopic impressions varied from a thickened area/fibrosis to mucosal erythema. Most patients were immunocompromised due to a disease state (e.g. organ transplantation, cancer diagnosis, autoimmune condition) and/or medication effect. Eight patients with malakoplakia were on immunosuppressive medications (8/23, 35%). Common immunosuppressed disease states included cancer (n = 9), autoimmune disease (n = 5), status post organ transplantation (n = 4), diabetes (n = 5), infection/sepsis (n = 3), and HIV/AIDS (n = 1). Some patients had multiple co-morbidities (i.e. diabetes and organ transplant). Twenty-one patients with malakoplakia were in an immunosuppressive state (21/23, 91%).

CASE A 66-year-old woman with polymyositis and recurrent urinary tract infections presented with lumbar pain and progressive lower extremity neuropathy. Imaging showed lytic destruction of the vertebral bone from L2 to L4 with extension into adjacent musculature. Histological examination demonstrated Michaelis-Gutmann bodies consistent with malakoplakia. The patient underwent revision T12-sacrum posterior fusion, L2-5 laminectomy, and anterior L3-4 corpectomy, followed by L2-4 anterior stabilization and a 6-week course of ceftriaxone. At 3 months postoperatively, she was asymptomatic without recurrence. CONCLUSION Malakoplakia of bone should be considered in the differential diagnosis of lytic bone lesions and can be effectively treated with surgical debulking with penetrative antibiotics.

Rationale: Malakoplakia and xanthogranulomatous pyelonephritis are chronic inflammatory conditions of the kidney characterized by the infiltration of inflammatory cells. Patient concerns: An 82-year-old female patient had a history of hypertension, type 2 diabetes mellitus, dyslipidemia, and end-stage renal disease under hemodialysis. She was admitted repeatedly 4 times within 4 months due to urosepsis. Diagnosis: The enlarged right kidney with a low-density lesion at the right middle calyx, and a well-enhanced ureter were noted on the computed tomography scan. Therefore, xanthogranulomatous inflammation was suspected. Semi-rigid ureteroscopy with biopsy was performed, and xanthogranulomatous inflammation of the ureter was confirmed on the pathology report. Interventions: After right open radical nephrectomy was performed, the final pathology report revealed malakoplakia with xanthogranulomatous pyelonephritis. Outcomes: After the surgery, she has no longer suffered from urosepsis for 8 months, and there were no adverse event or recurrence noted. Lessons: With this case report, we aim to emphasize that these 2 diseases are not mutually exclusive, but they may exist simultaneously in the same patient.

Introduction Malakoplakia is a rare chronic inflammatory disorder, predominantly affecting the urinary tract. In the head and neck region, it is very rare and may confuse the clinicians during investigations, as features may mimic malignancy. Materials and methods We report a case of malakoplakia involving the parotid gland and review of the reported cases of malakoplakia in head and neck region. Results Histologically, this is the first classic case report of malakoplakia involving the parotid gland in the world literature. A total of 49 cases have been reported in the head and neck region; 38.7% of these are cutaneous. In soft tissue, the tongue is the most common site. Salivary gland involvement is very rare. Previously, submandibular salivary gland involvement has been reported. Conclusion A possibility of malakoplakia should be considered as a differential diagnosis in patients with enlarged head and neck masses. Histology is essential to diagnose this benign inflammatory disorder and to differentiate from a malignant process.

Summary Antibodies targeting uroplakin II (UPII) are highly specific for urothelial cells and are frequently used to determine if a primary bladder lesion or a metastatic lesion originates from the urothelium. However, to date, no studies have tested the expression of UPII in histological mimickers of bladder cancer that are nonurothelial in origin. Given the potential risk of misdiagnosis, immunohistochemical markers are often used to better characterize these lesions. In the present study, we analyzed the immunohistochemical expression of UPII in a set of urothelial carcinoma mimickers that included conventional nephrogenic adenoma (n = 8), papillary nephrogenic adenoma (n = 6), endometriosis/endosalpingiosis (n = 5), inflammatory myofibroblastic tumor (n = 4), ectopic prostate tissue (n = 2), and malakoplakia (n = 2). We also examined the expression of GATA-3, another commonly used immunohistochemical marker in bladder cancer diagnosis, in the same lesions. Weak immunoreactivity for UPII was identified in 6 of 27 mimickers (22%), and GATA-3 was expressed in 16 of 27 mimickers (59%). Strong immunoreactivity for UPII appeared to be a specific marker for urothelial cell of origin, although weak staining was seen in a significant proportion of mimickers. GATA-3 immunostaining was present in a greater number and broader spectrum of mimickers; however, only one case of papillary nephrogenic adenoma showed dual positivity for UPII and GATA-3. These findings support the immunohistochemical panel-based approach in the diagnosis of bladder lesions, especially if nonurothelial bladder cancer mimickers are in the differential diagnosis. Additional larger studies would be of value to expand on these findings.

Malakoplakia is an inflammatory process related to defective macrophage response to bacterial infection. To further characterize the clinicopathologic manifestations of gastrointestinal malakoplakia, 26 cases were identified from 6 institutions. Hematoxylin and eosin-stained slides and available stains were reviewed, and pertinent clinicopathologic features analyzed. Sixteen patients were women (62%). Mean patient age was 64 (range: 24 to 83). Sites included the colorectum (n=23), appendix (n=1), and stomach (n=2). Clinical indications for tissue procurement included screening (n=14), tumor resection (n=5), diarrhea (n=1), adenoma surveillance (n=1), ulcerative colitis flare (n=1), abdominal pain (n=1), and appendicitis (1). All cases featured histiocytes with abundant, pale, eosinophilic cytoplasm focally containing Michaelis-Gutmann bodies. The process frequently involved the mucosa (n=19), with architectural distortion in 13 cases. Lymphoid aggregates were present in 18 cases, which were prominent or obscuring in 11 (all colon biopsies) and provoked concern for lymphoma in 2. Associated findings included adenocarcinoma (n=5), adenoma (n=2), gastric hyperplastic polyps (n=1), chemical gastritis (n=1), collagenous colitis (n=1), and active chronic colitis (n=2). In cases with available stains, Michaelis-Gutman bodies were highlighted by Periodic Acid-Schiff with diastase, Von Kossa, and iron stains. Although 2 cases were positive for Tropheryma whipplei antibody, no T. whipplei transcripts were detected on real-time polymerase chain reaction. All patients with available follow-up are alive and well with no additional instances of malakoplakia. Malakoplakia of the gastrointestinal tract is a benign, incidental finding. Although histologic features in the stomach and colon resections are similar to those at other sites, exuberant lymphocytic response in colon biopsies and immunoreactivity with T. whippleii antibody may provoke initial confusion and lead to unnecessary time and resource investment.

Malakoplakia is a rare, granulomatous disease that affects a wide variety of organs and can have a clinical and radiographic presentation resembling that of malignancy. The genitourinary tract is the most commonly involved site. There are scant reported cases presenting as a locally advanced renal mass and even rarer, diagnosed by fine-needle aspiration (FNA) cytology. We report clinical, imaging, cytologic, and histological findings of an interesting case of malakoplakia initially diagnosed by FNA cytology. We also briefly review the literature and emphasize the importance of recognizing this entity when encountered in an aspirate material, which can help mitigate the diagnostic confusion of malakoplakia for clinicians.

The alimentary tract serves as host to a large number of diseases. In the non-neoplastic group of disorders, conventional histochemistry continues to play an important diagnostic role. It is particularly important in recognizing specific infectious diseases, such as Helicobacter gastritis, Whipple disease, intestinal tuberculosis and other forms of mycobacteriosis, malakoplakia, intestinal spirochetosis, fungal enteritides, amebiasis, cryptosporidiosis, isosporiasis, and microsporidiosis. Those conditions and their histochemical properties are discussed in this review, along with the use of histochemistry in the characterization of structural gastrointestinal disorders. The latter include mucosal metaplasias, amyloidosis, glycogenic acanthosis of the esophagus, lymphocytic-collagenous colitis, gastric neuroendocrine hyperplasia, and pill gastritis.

Malakoplakia is a rare condition in which histiocytic cells accumulate within different organs and tissues, sometimes mimicking neoplasia. Gynecologic involvement is extremely rare and therefore may cause relevant diagnostic confusion for both clinicians and pathologists. In this paper, we described the seventh case of ovarian malakoplakia, and we reviewed the literature to compare it with the previously reported ones. Moreover, we investigated the histologic and molecular differential diagnosis of malakoplakia, with special attention to other histiocytic disorders of gynecologic interest. Finally, we discussed the most relevant points with regard to possible pathogenesis and management. Malakoplakia often represents a forgotten entity that should be remembered preoperatively, when approaching a possible gynecologic neoplasia. Moreover, it is of remarkable importance to differentiate malakoplakia from multisystem histiocytosis involving gynecologic organs. All this would prevent misdiagnosis and overtreatment of such a rare but benign condition.

Malakoplakia, a rare acquired granulomatous disease, affects many systems, including the urogenital tract. The literature describes malakoplakia of different viscera, and satisfactory results have been obtained after treatment. We reported a 48-year-old patient with diabetes who received multiple treatments in our hospital for bladder malakoplakia near the ureteral orifice. Despite aggressive treatment, the patient had recurrent bladder malakoplakia and even developed right ureteral orifice stenosis, which resulted in urinary obstruction and hydronephrosis. We believe that malakoplakia in the bladder near ureteral orifice should receive more attention. Satisfactory results may not be obtained through antibiotic treatment alone, and early antibiotic therapy combined with full surgical excision may be a better choice.

A 45-year-old woman presented to us in March 2019 with complaints of fever and right lower quadrant abdominal pain for 1 month. She had undergone renal transplantation in 2017 for end-stage renal disease and developed four episodes of urinary tract infection in the next 16 months post transplantation, which were treated based on culture reports. She was subsequently kept on long-term prophylaxis with trimethoprim and sulfamethoxazole. Her present laboratory parameters showed a normal blood picture and elevated creatinine. Urine culture grew Escherichia coli. Non-contrast CT of the abdomen-pelvis revealed an endo-exophytic hyperdense mass in the graft kidney showing local infiltration and associated few regional lymph nodes. PET-CT revealed the soft-tissue mass and regional lymph nodes to be hypermetabolic, raising the possibility of lymphoma. However, biopsy showed features of malakoplakia. She was subsequently initiated on long-term antibiotic therapy and her immunosuppression decreased.

This article provides pictorial review of complicated upper and lower genitourinary infections and their mimics. Imaging features of upper urinary tract infections including uncomplicated acute pyelonephritis, xanthogranulomatous pyelonephritis (XGPN), emphysematous pyelonephritis, perirenal abscess, and pyonephrosis are first reviewed and then followed by pictorial review of their mimics including contrast-associated nephrotoxicity, renal infarcts, malakoplakia, renal cell cancer, leukemia or lymphoma and Castleman's disease. Next, imaging features of lower urinary tract infections including cystitis, emphysematous cystitis, enterovesical, colovesical and vesicovaginal fistulas, Fournier gangrene, prostatitis, epididymitis, and orchitis are reviewed and then followed by pictorial review of their mimics including gas in the bladder and perineum related to instrumentation, radiation cystitis, bladder cancer, testicular torsion, testicular trauma, and testicular cancer and lymphoma. Recognizing imaging characteristics of complicated genitourinary infections and their mimics would allow clinicians to provide appropriate timely management.

Background Malakoplakia is a chronic inflammatory disease characterized by tissue infiltrates of large granular macrophages containing distinctive intracytoplasmic inclusions termed Michaelis-Gutmann (MG) bodies. The genitourinary system is the most commonly involved site, followed by the gastrointestinal tract. Malakoplakia may occur as a complication of primary or secondary immunosuppression and, therefore, renal transplant recipients are at risk. The graft itself or extra-renal sites may be involved. Regarding the latter, six cases of colorectal malakoplakia have been reported following renal transplantation, with all but one patient experiencing significant morbidity. We describe a further example of colorectal malakoplakia following renal transplantation. The other previously reported cases are reviewed. Case presentation A 72 year old female presented with left lower quadrant abdominal pain and vaginal bleeding. She had received a cadaveric renal transplant for chronic renal failure ten months previously. Abdomino-pelvic computerized tomography (CT) scanning demonstrated two lesions in the mesocolon: the first adjacent to the descending colon and the second involving the sigmoid colon. A diagnosis of sub-acute perforated diverticulitis with two phlegmons was proposed. The sigmoid lesion was resected. The descending colon lesion was treated by creation of a cutaneous fistula. Microscopy of the sigmoid lesion showed the typical features of malakoplakia. She was discharged on sulfamethoxazole-trimethoprim. Nine months later, no longer receiving antibiotic therapy, the patient reported lower left quadrant discomfort. CT scanning showed para-rectal and pelvic abdominal masses with cutaneous and intestinal fistulas. Treatment with tazobactam-piperacillin was begun and sulfamethoxazole-trimethoprim was reinstated, with subsequent slow clinical improvement. Subsequent abdominal CT scans have shown persistence of the lesions. Conclusions Physicians caring for renal transplant recipients should be aware of colorectal malakoplakia as a rare but serious complication. The onset may be within months or as long as a decade or more following transplantation. The clinical presentation is varied, nonspecific, and will likely suggest more common diseases. Although radiologic imaging is also nonspecific, awareness of malakoplakia is of importance to radiologists when formulating the differential diagnosis of mass lesions of the colorectum in this clinical setting. Definitive diagnosis remains dependent on pathologic examination of a biopsy or surgical resection specimen.

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 co-morbidities owing largely to misdiagnoses and the similar appearance to malignancy or granulomatous processes. Most patients are immunocompromised, including the solid organ transplant population. Amongst organ recipients, malakoplakia is most commonly seen in renal transplantation, and only rarely reported in thoracic organ recipients. Here, we report two cases of malakoplakia in thoracic transplant patients that highlight the critical need for tissue diagnosis to avoid delay in management.

Malakoplakia, a rare granulomatous disease of infectious etiology, is commonly observed in immunocompromised patients. Chronic lymphocytic leukemia (CLL) is characterized by profound immune dysregulation resulting in significant infection-related morbidity and mortality, and several drugs used in CLL treatment have a severe immunosuppressive effect. Ibrutinib, has become a new standard-of-care in patients with CLL, especially for those harboring unfavorable genetic characteristics such as 17 p deletion, with however, unknown long-term immunological consequences. Here we report a case of a patient with CLL with 17 p deletion diagnosed with malakoplakia of the urinary bladder under ibrutinib therapy who developed severe hypogammaglobulinemia during treatment administration. Presumably, ibrutinib might contribute to the development of malakoplakia on the grounds of induced immunosuppression. This case report highlights the need for regular assessment of immunogammaglobulin adequacy during treatment with ibrutinib, considering that it should be given on a permanent basis.

Malakoplakia is a rare histiocytic disease first described in 1902 by Michaelis and Gutmann. It is associated with host immunocompromise including chronic inflammatory conditions, infectious conditions or malnutrition. Here, we report the case of uterine malakoplakia as a rare cause of postmenopausal bleeding in an immunocompromised patient.

The objective of this study was to highlight the role of multimodality imaging and present the differential diagnosis of abnormal tracer accumulation in the prostate and periprostatic tissue. Our departments have performed molecular imaging of the prostate utilizing PET-CT and PET-MRI with a range of biomarkers including F-FDG, radiolabelled choline, Ga-DOTATATE PET-CT and Ga-PSMA images. We retrospectively reviewed the varying appearances of the prostate gland in different diseases and incidental findings in periprostatic region. The differential diagnosis of pathologies related to prostate and periprostatic tissue on multimodality imaging includes malakoplakia, rhabdomyosarcoma, lymphoma, prostate cancer, neuroendocrine tumours, uchida changes, rectoprostatic fistula, synchronous malignancies, lymphocoele and schwanoma. There exists a wide differential for abnormal tracer accumulation in the prostate gland. As a radiologist and nuclear medicine physician, it is important to be aware of range of prostatic and periprostatic pathologies.

Rationale: Malakoplakia is a rare disease characterized by the presence of nongranulomatous macrophage infiltration. In most cases, it affects the urinary tract. Malakoplakia can cause acute kidney injury when it is localized in the kidneys. Patient concerns: Here, we report the case of a 65-year-old female patient with renal malakoplakia responsible for hypercalcemia. During her initial assessment, she was also diagnosed 25-OH vitamin D insufficiency, for which she was prescribed oral cholecalciferol. Three months later, she developed severe hypercalcemia with normal 25-OH vitamin D and parathyroid hormone levels and high 1,25-dihydroxyvitamin D levels. Diagnoses: After a superimposed granulomatous disease was excluded, malakoplakia cells were suspected to be responsible for the abnormal 25-hydroxyvitamin D3 1-alpha-hydroxylase activity, which was confirmed by immunohistochemistry. Interventions: Cholecalciferol was stopped, the patient was rehydrated with intravenous physiological saline, and prednisone was initiated to decrease the enzyme activity. Outcomes: Six months later, she displayed normal serum calcium, 25-OH vitamin D and 1,25-dihydroxyvitamin D levels. Lessons: This case illustrates that malakoplakia may exhibit ectopic 25-hydroxyvitamin D3 1-alpha-hydroxylase activity and cause severe hypercalcemia upon vitamin D supplementation. Therefore, such supplementation should not be given in malakoplakia patients without an actual deficiency and requires careful monitoring of serum calcium.

A 32-year-old woman named A.C. was diagnosed five years ago with stage IIIB nodular sclerosing Hodgkin lymphoma (HL). Following initial chemotherapy, she had refractory disease as evidenced by hypermetabolic activity on positron-emission tomography (PET) scan. A.C. was treated with a short course of salvage chemotherapy, stem cell collection, and autologous HSCT about 11 months after initial diagnosis. Her post-transplantation course was complicated by pneumonia and interstitial lung disease secondary to chemotherapy that rapidly improved with high-dose steroids .

Malakoplakia is a rare granulomatous disease that commonly involves the genitourinary tract, with the urinary bladder being the most frequently affected site. Grossly, malakoplakia can present as soft yellow plaques, nodules, bladder mass, or even without any visible lesion. In this article, we present a 74-year-old female with a background of hypertension, hyperlipidemia, and poorly controlled diabetes who presented with sepsis of unknown origin. During the course of the investigation of the source of her sepsis, an incidental bladder tumor was discovered. She subsequently underwent transurethral resection of the bladder tumor. Histology revealed ordinary low-grade papillary urothelial carcinoma that had small colonies of malakoplakia that appeared to have developed secondary to the tumor and presented concurrently. We seek to demonstrate the rare association of papillary urothelial carcinoma and malakoplakia.

Histiocytic disorders of the chest comprise a broad spectrum of diseases. The lungs may be involved in isolation or as part of systemic disease. Some of these disorders are primary and have unknown etiology, and others result from a histiocytic response to a known cause. Among primary histiocytic disorders, pulmonary Langerhans cell histiocytosis (PLCH) is the most common; others include Erdheim-Chester disease and Rosai-Dorfman disease. Adult PLCH occurs almost exclusively in adults aged 20-40 years who smoke. Pediatric PLCH is extremely rare and typically occurs as part of multisystemic disease. Erdheim-Chester disease affects middle-aged and older adults; thoracic involvement usually occurs as part of systemic disease. Rosai-Dorfman disease affects children and young adults and manifests as painless cervical lymphadenopathy. Examples of secondary histiocytic disorders are storage diseases such as Gaucher disease, Niemann-Pick disease, and Fabry disease; pneumoconiosis such as silicosis and coal workers' pneumoconiosis; and infections such as Whipple disease and malakoplakia. These disorders are characterized at histopathologic examination on the basis of infiltration of alveoli or the pulmonary interstitium by histiocytes, which are a group of cells that includes macrophages and dendritic cells. Dendritic cells are a heterogeneous group of nonphagocytic antigen-presenting immune cells. Immunohistochemical markers help to distinguish among various primary histiocytic disorders. Characteristic radiologic findings in the appropriate clinical context may obviate biopsy to establish a correct diagnosis. However, in the absence of these findings, integration of clinical, pathologic, and radiologic features is required to establish a diagnosis.

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.

Malakoplakia, a rare granulomatous disease caused by impaired macrophage response, has been reported only rarely in children. We report 3 unique cases, with lesions occurring in unusual locations in children with primary immune deficiencies.

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.

Malakoplakia (from the Greek malakos, ‘soft’ and plakos ‘plaque’) is a granulomatous inflammatory condition, commonly presenting as a plaque in the genitourinary system, but has been shown to affect a wide variety of structures including the skin. Presentation is varied and a high degree of clinical suspicion is needed to make a diagnosis. We report a case of cutaneous malakoplakia presenting as an inguinal swelling in a 48-year-old kidney transplant patient with temporally associated graft dysfunction. New groin swelling in an immunosuppressed patient often prompts investigation centred on a malignant cause. While this is often appropriate, less common infectious and inflammatory causes should be considered. This case highlights the importance of thorough workup and investigation, including histopathology, in immunosuppressed cohorts and acts as a reminder that less common and more complex diagnoses warrant consideration in this group.

Malakoplakia is a rare acquired disease that can affect many systems but is more common in the urogenital tract. Cutaneous malakoplakia is even rarer. It is far more frequent in immunodeficient patients. We report a case of cutaneous malakoplakia in a kidney transplant patient who had recently stopped receiving immunosuppressive therapy to illustrate a review of the relevant recent literature.

Malakoplakia is a granulomatous disease associated with an infectious etiology, usually involving the urinary tract. It reveals itself as a recurrent urinary tract infection (r-UTI), and in some cases, it is associated with impairment of renal function. Immunosuppression is one of its main associated factors, and it has been increasingly described in patients with solid organ transplantation (SOT), mainly kidney transplantation. Macroscopically, it can form masses and sometimes it may be confused with neoplasia, which is why histological findings are fundamental for the diagnosis. Here, we present a case of bladder malakoplakia, manifested by r-UTI from Escherichia coli in a patient with renal transplantation, refractory to long-term antibiotic treatment and reduction in immunosuppression, which resolved after surgical management. We also summarize the clinical characteristics of malakoplakia and compare them with previous reports in the literature on SOT.

Surgical pathology results can play a crucial role in the management of immunocompromised patients. Here we highlight factors that differ between immunocompromised and immunocompetent hosts, such as variation in inflammatory response. Conditions that are covered include drug reactions, disease within solid organ allografts, immune reconstitution inflammatory syndrome, specific immunodeficiency syndromes, neoplasms related to viral infections, and viral, bacterial, fungal, and parasitic infections. Special techniques including immunohistochemistry, in situ hybridization and molecular detection of pathogen nucleic acid from formalin-fixed, paraffin-embedded tissue are discussed.

Malakoplakia is a rare inflammatory condition that typically occurs in the urinary tract. The cutaneous form is less prevalent, and most commonly occurs in the perianal or genital regions. Here we present a 61 year old lady with cutaneous malakoplakia of the neck, which was successfully treated with surgical excision and a prolonged course of ciprofloxacin. We follow our case report with a discussion and literature review of all seventeen previously reported cutaneous head and neck malakoplakia cases from the literature. A diagnosis of cutaneous malakoplakia should be considered in nodular, ulcerated or discharging lesions that are refractory to treatment. Histology is essential, not only to diagnose malakoplakia, but also to exclude other important differential diagnoses, such as malignancy. Combined surgical excision and prolonged antibiotic courses appear to have the highest success rate. Antibiotics should be culture specific, but quinolones appear to be the best empirical choice.

La malakoplakie est une maladie inflammatoire granulomateuse chronique, qui affecte généralement le tractus génito-urinaire et exceptionnellement la glande mammaire. Il faut savoir évoquer ce diagnostic devant une mastite pseudotumorale. Sa définition est anatomopathologique. Nous rapportons un cas inhabituel de malakoplakie mammaire chez une patiente ayant des antécédents de tuberculose. L'imagerie était en faveur d'une mastite carcinomateuse. L'analyse histologique de la biopsie mammaire révélait une inflammation granulomateuse faite d'histiocytes renfermant des granulations pathognomoniques de Michaelis-Gutmann. La patiente était mise sous traitement médical à base de ciprofloxacine avec bonne évolution clinique et radiologique après un recul d'un mois.

Malakoplakia is a rare chronic granulomatous disease of unknown cause. It is thought to be caused by an acquired bactericidal defect of macrophages. Malakoplakia is associated with chronic infections and immunosuppression. Although it occurs mainly in the urinary tract, it has already been reported in almost every organ system. The isolation of bacteria, especially Escherichia coli, is common in malakoplakia patients. Here, we present a case of primary cutaneous malakoplakia in a kidney transplant recipient who had been taking prednisone, tacrolimus, and mycophenolate. Culture of a lesion grew Burkholderia cepacia complex. Treatment with high doses of trimethoprim-sulfamethoxazole was successful. We also present a systematic review of the literature, identifying 4 previously reported cases of malakoplakia after renal transplantation under similar immunosuppressive therapy, most occurring in the urinary tract or perineum and following benign courses to cure. Data in the literature suggest that malakoplakia has become even rarer since changes were made in the immunosuppressive therapy employed after kidney transplantation.

This is a case report of a 65-year-old female with malakoplakia in the urinary bladder. An ultrasound scan showed many tumor-like polyp lesions, where a transurethral resection was performed. Since the lesions revealed gross papillary neoplasms, malignancy was suspected. However, histpathological examination showed an aggregation of many infiltrating histiocytes containing characteristic Michaelis-Gutmann bodies positively reactive with von Kossa staining, indicating a typical case of malakoplakia of the urinary bladder. Immunohistochemical study demonstrated that the cytoplasms of the histiocytes were focally positive for an anti-Escherichia coli antibody. One of the etiologies of malakoplakia is infection by Escherichia coli, which is supported by our data.

Idiopathic granulomatous orchitis is a rare inflammatory process of the testis of unknown etiology. It is characterized by presence of non-specific granulomatous inflammation and admixed multinucleated giant cells. It usually presents as a testicular mass which is highly suspicious of malignancy. Histologically, there is extensive destruction of seminiferous tubules with tubular or interstitial pattern of granulomatous inflammation and prominent collagen fibrosis. Trauma and possible auto-antibodies against sperms have been postulated to be the underlying mechanism. Differential diagnoses include intratubular germ-cell neoplasia, malignant lymphomas, and malakoplakia. Orchiectomy is currently the most appropriate therapy for this condition.

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.

Malakoplakia is a rare chronic inflammatory condition characterized by defective macrophage function, most of which involve the genitourinary tract, and renal parenchymal involvement is uncommon. We present a case of malakoplakia affecting renal parenchyma. A 46-year-old woman with pyrexia and jaundice was referred to our department. Abdominal enhanced CT scan revealed a left pyelonephritis with ureteral stone and bilateral renal abscesses. Despite the insertion of a left ureteral stent and administration of antibiotics, the patient showed persistent high fever and elevated CRP, and no obvious improvement in clinical and imaging data. In view of the limited effectiveness of the conservative treatment in this case, we decided to perform left nephrectomy. The diagnosis of malakoplakia was made based on the histopathological findings of von Hansemann cells and Michaelis-Guttmann bodies detected in the nephrectomy specimen. She is clinically healthy up to the present (50 months after surgery) with normal clinical indicators and CT findings.

Background. Malakoplakia is a very rare chronic inflammatory disorder, first described in 1902. In 75% of cases, the condition affects the genitourinary tract. Five cases of malakoplakia affecting the neck were previously reported in the literature. Methods and Results. An 83-year-old woman presented with an enlarging mass in the posterior triangle of the neck that was histologically confirmed as malakoplakia. Presenting features are often nonspecific, and the diagnosis is dependent on histological findings. The characteristic microscopic findings are of Michaelis–Gutmann (M-G) bodies that stain positive with periodic acid–Schiff reagent, von Kossa's reaction for calcium, and Perl's ferrocyanide reaction to ferric iron. Conclusion. Although rare, a diagnosis of malakoplakia should be considered in patients with an enlarging mass. This may mimic the presentation of malignancy, particularly in patients in whom erosion through skin occurs, and histological confirmation is advocated. © 2009 Wiley Periodicals, Inc. Head Neck 32:1269–1272, 2010

An autopsy case of malakoplakia involving the kidney and prostate was reported. The case was a 58-year-old Japanese male with submassive hepatic necrosis of three and half months' duration. He received 20 to 40 mg of prednisolone daily during the course of the disease (total 2,700 mg). Malakoplakic lesions were incidentally found in the right renal parenchyma and prostate at autopsy. The lesions were characterized microscopically by an accumulation of macrophages with PAS-positive intracytoplasmic granules and with intracytoplasmic inclusions of owl's eye appearance called Michaelis-Gutmann bodies and, electronmicroscopically, by numerous phagolysosomes with varying numbers of bacteria. Immunocytochemical stain revealed that the bodies were positive for lysozyme, indicating that the Michaelis-Gutmann bodies are of lysosomal origin. No calcium, phosphorous, and iron were demonstrated in them by X-ray microanalysis, suggesting that they are of immature form in which a mineralization does not take place as yet. Malakoplakia has not been previously described in association with submassive hepatic necrosis. Administration of a large amount of steroid for the treatment of submassive hepatic necrosis was suspected to be implicated in the development of the malakoplakia in the present case.

Context.—Malakoplakia is a rare granulomatous disease that occurs commonly in the urinary tract. Histologically, it is defined by sheets of histiocytes (Hansemann cells) with accumulation of granular basophilic periodic acid-Schiff– positive, diastase-resistant inclusions and calcified Michaelis-Gutmann bodies, which are pathognomonic but not necessary for diagnosis. In addition to the urinary tract, malakoplakia has been reported in other organs, including the gastrointestinal tract, central nervous system, female genital tract, and the tongue. Objectives.—To review the literature of reported sites of malakoplakia outside the urinary tract and their variable clinical presentations, and to discuss the main diagnostic features and differential diagnoses of malakoplakia. The pathogenesis and possible etiologic factors are also presented. Data Sources.—Data for this work were collected from the published literature, textbooks, and the Internet. Conclusions.—It is important to be aware of the existence of this entity in abnormal locations. In many situations, malignancy can be mimicked, especially when the lesion is ulcerated and is accompanied by lymph node involvement. Misinterpreting large, rapidly growing nodules of malakoplakia as tumor might lead to overstaging. Pathologists should be also aware of the possibility of malakoplakia coexisting with other lesions, such as tuberculosis and carcinoma, in the same specimen.

Malakoplakia is a rare inflammatory disorder that results from an infectious process and that may be associated with immunosuppression. It most often occurs in the genitourinary tract; however, isolated cases have been reported in many other organs, including colon, stomach, lung, liver, bone, uterus, and skin. In the bladder, which is the most common site of involvement, it may be mistaken for malignancy on cystoscopic examination or computerized topography scan. Gram-negative bacteria such as Escherichia coli and Klebsiella pneumonia are often isolated from malakoplakia lesions, although other less common bacteria such as Rhodococcus equi may also be found. This is a case report of prostatic malakoplakia diagnosed on needle core biopsy from a patient suspected to harbor a malignancy.