Renal cholesterol granulomas: identification and morphological pattern of development

[Renal granulomatous nephritis: Histopathological point of view]

Granulomatous interstitial nephritis (NIG) is a rare form of interstitial nephritis that can be related to acute or chronic clinical presentation. NIG is characterized by granulomas located to the renal interstitium and composed of either epithelioid histiocytes with giant cells and/or of foreign body reaction. The symptoms are unspecific and associate varying degrees of renal failure with abnormal urinanalysis. Extra-renal signs may point to systemic disease. Pathological examination from kidney percutaneous biopsy or surgical resection is required to assert NIG diagnosis and to guide the etiological research. The main causes of NIG are sarcoidosis, drug reactions, mycobacterial infections and crystalline nephropathies. Sarcoidosis is characterized by non-necrotic and well-formed giant cell epithelioid interstitial granulomas. Drug reactions have less well-defined granulomas with inconstant eosinophils. The presence of caseous necrosis within giant cell and epithelioid granulomas leads to infectious NIG diagnosis (tuberculosis and fungal infection). Identification of crystals within foreign body reaction can be improved by polarized light study. Xanthogranulomatous pyelonephritis and malakoplakia are rarer causes of NIG characterized by patches of histiocytes associated with inconstant giant cells. Differential diagnoses of NIG are represented by granulomatous reactions centered on glomeruli and vessels (vasculitis and emboli of cholesterol crystals). Less than 10% of NIG are idiopathic. The prognosis and the treatment vary according to the cause. The factors of poor renal prognosis are chronic irreversible tubulo-interstitial injury (tubular atrophy and interstitial fibrosis).

Investigating mitochondrial autophagy by routine transmission electron microscopy: Seeing is believing?

Mitochondrial autophagy is affected in many diseases. In the past few years, the multiple-steps process of selective degradation of mitochondria has been dissected in details by combining outcomes from different approaches. Perhaps one of the most rigorous methods to clearly visualise mitochondria undergoing autophagic engulfment and degradation, is transmission electron microscopy (TEM). In this opinion paper, we want to give a brief summary of the mitophagic process, and by which means mitophagy can be addressed, including TEM analysis. We will report examples of autophagy and mitophagy-related TEM images, and discuss how to decipher the different steps of the mitophagic process by routine TEM. In our opinion, this technique can be used as a powerful confirmatory approach for mitochondrial autophagy and can provide details of the organelle fate throughout the course of mitophagy with no substantial sample manipulation.

Cholesteroloma of the breast: A 10 year retrospective review of 79 cases with radiology correlation

A cholesteroloma or cholesterol granuloma of the breast is an uncommon lesion representing an inflammatory/reactive process with unclear etiology. In this study, we reviewed our 10-year experience with cholesteroloma of the breast with clinical, radiologic, and histopathological correlation. Seventy-nine cases were selected. The mean patient age was 57.7 (range 25-90) years old. Patients had hypercholesterolemia with mean blood cholesterol level of 201 mg/dL (P < 0.001). The mean body mass index (BMI) was 26.7 kg/m² (P = 0.1976). The indications for the breast biopsies were mass lesion on radiology (85.5%, n = 65) and microcalcifications (10.5%, n = 8). Of the 65 cases of the mass lesions, 52 presented as solid masses and 13 were cystic. On the diagnostic mammogram or ultrasound, 81.9% were BI-RADS 4% and 6.9% were BI-RADS 5. Macrocysts were the most common pathological finding associated with cholesteroloma suggesting the etiology of cholesteroloma may be the result of repair process from obstruction and rupture of the macrocysts. Six cases (9.2%) of cholesterolomas had persistent masses during follow-up. The recognition of this lesion and radio-pathological correlation can help us better understand this entity and distinguish it from its mimickers.

[Cholesterol granuloma of the kidney: a case report]

A 58-year-old woman was referred to our outpatient clinic for further examination of a mass detected in the right kidney on follow-up ultrasonography performed for active surveillance of right ovarian cancer. Ultrasonography and computed tomography showed a cyst (diameter, 30 mm) with an irregular wall in the middle of the right kidney. Right nephrectomy was performed since malignancy was suspected. Histological findings of the mass indicated cholesterol granuloma. Although cholesterol granulomas in the middle ear have been frequently reported, those in other organs have been reported in few studies. In this patient, the cholesterol granuloma could be barely distinguished from the cancer by using imaging techniques.

Cholesterol granuloma of the maxillary sinus encountered during floor augmentation procedure: A case report

BACKGROUND

Cholesterol granuloma (CG) is a foreign-body reaction to the deposition of cholesterol crystals. Its occurrence in the paranasal sinuses is very rare.

PURPOSE

This report describes a new case of maxillary sinus CG discovered incidentally during sinus-floor augmentation for dental implant placement in a 60-year-old female patient.

MATERIALS AND METHODS

The preoperative clinical and radiological examinations revealed a normal maxillary antrum with no evidence of sinus pathology. After lateral osteotomy, a dark-green, viscous soft tissue mass appeared through the thin mucous membrane inside the sinus. Enucleation and curettage of the sinus contents including the sinus membrane were performed for histopathologic analysis. The augmentation and implant placement procedures were postponed.

RESULTS

Histopathologic analysis showed several fragments of granulation tissue containing diffuse cholesterol clefts surrounded by mixed chronic inflammatory cell infiltrate including plasma cells and lymphocytes. These features were compatible with the diagnosis of CG. The patient was followed up for 3 months after the first procedure, and a second attempt of sinus augmentation and dental implant insertion was then carried out. The inserted dental implants were followed up for 6 months without any complications.

CONCLUSIONS

CG of maxillary sinus can be an incidental finding. For this reason, the final diagnosis can only be achieved after examination of the material under the microscope.

Cholesterol granuloma of the breast with unusual ossification features (osseous metaplasia)

Cholesterol granuloma of the breast is a rare benign condition that can be mistaken for breast cancer. We present a case of a 42-year-old woman who presented with a 1-year history of asymptomatic palpable nodule in the upper external quadrant of the right breast. Mammography and ultrasonography suggested carcinoma, but excisional biopsy revealed cholesterol granuloma with unusual osseous metaplasia. Although reported to occur more frequently in the middle ear and mastoid process, we believe that better awareness of this rare benign condition is most important to avoid misdiagnosis and unnecessary surgery.

A Case of Breast Cholesterol Granuloma Accompanied by Cancer

Cholesterol granuloma of the breast is a very rare benign disease with clinical and imaging features that are often indistinguishable from cancer preoperatively. We report a case of breast cholesterol granuloma accompanied by cancer. The patient was a 78-year-old woman who complained of a lump in her right breast. Mammography and ultrasonography showed a well-circumscribed mass. Fine needle aspiration cytology showed many cholesterol crystals and inflammatory cells without malignancy. With a diagnosis of cholesterol granuloma, tumor extirpation was performed. Histopathologic examination revealed cholesterol granuloma together with breast cancer, and additional partial mastectomy was subsequently performed. It is noted that breast cholesterol granuloma could be accompanied by cancer.

A new theory to explain the genesis of petrous apex cholesterol granuloma

OBJECTIVE

To propose a new hypothesis that attempts to explain the pathogenesis of petrous apex cholesterol granuloma (PA CG). CLASSIC OBSTRUCTION-VACUUM HYPOTHESIS: PA CGs form when mucosal swelling blocks the circuitous pneumatic pathways to the apical air cells. Trapped gas resorption results in a vacuum that triggers bleeding, and CG forms through anaerobic breakdown of blood products. PROBLEMS WITH THE CLASSIC (OBSTRUCTION-VACUUM) HYPOTHESIS: Impaired ventilation of mucosa-lined pneumatic tracts in the middle ear, mastoid, paranasal sinuses, and lung are very common, but CG is rare. The extraordinary levels of temporal bone pneumatization typically observed in PA CG cases is indicative of excellent ventilation and freedom from inflammatory mucosal disease. Were under pressure due to gas absorption alone sufficient to trigger hemorrhage, CG ought to be frequent in otitis media with effusion.

PATIENTS

The opposite PA of 13 patients with PA CG compared with 31 highly pneumatic PAs in patients undergoing imagery for non-otologic reasons.

MAIN OUTCOME MEASURE

The nature of the bony partition, as seen on computed tomography, between the PA air cell system and the adjacent marrow compartment.

RESULTS

4 of 13 PAs with CGs on the opposite side showed deficient septation between air cells and marrow, whereas this was not observed in any of the 31 extensively pneumatized normal ears. NEW HYPOTHESIS (EXPOSED MARROW): As cellular tracts penetrate the apex during young adulthood, budding mucosa invades and replaces hematopoietic marrow. The bony interface becomes deficient, with coaptation of richly vascular marrow and the mucosal air cell lining. Hemorrhage from the exposed marrow coagulates within the mucosal cells and occludes outflow pathways. Sustained hemorrhage from exposed marrow elements provides the engine responsible for the progressive cyst expansion. As the cyst expands, bone erosion increases the surface area of exposed marrow along the cyst wall. This exposed marrow theory explains the unique proclivity of the healthy and well-pneumatized PA to form a CG.

Two cases of cholesterol granuloma of the breast

We report two cases of cholesterol granuloma of the breast clinically diagnosed as malignant and describe the features. The first patient was a 74-year-old woman who complained of a lump in the left breast. The mammography and ultrasonography suggested a malignant mass. Fine needle aspiration showed multinucleated giant cells. We suspected breast cancer, but cholesterol granuloma was diagnosed on excisional biopsy. The second case was a 51-year-old woman who was found to have a breast tumor on a screening mammography. The mammography and ultrasonography suggested carcinoma, but excisional biopsy revealed cholesterol granuloma. Reports of cholesterol granuloma of the breast are very rare. Cholesterol granuloma should be considered in the differential diagnosis of breast carcinoma.

Cholesterol granuloma of the breast presenting as an intracystic papilloma

Cholesterol granuloma of the breast is a rare benign condition. It is often clinically and radiologically indistinguishable from breast carcinoma. A case of cholesterol granuloma which manifested as an intracystic papilloma on ultrasound is described. This unusual ultrasonographic appearance has not previously been reported.

Calcium oxalate and other crystals associated with kidney diseases and arthritis

The recognition of tissue deposits of crystalline material in a variety of organs, including the kidney, predated the association of crystals and arthritic disease. Because of this, the pathophysiology of crystal formation and its resultant inflammation is based in part on studies of renal stones. A number of disease states involving renal and articular crystallization exist. The most common of these, uric acid precipitation, or gout, and calcium phosphate precipitation were not reviewed in this discussion. This review described a variety of less common disease states involving articular and renal crystal deposition. The renal diseases discussed included both parenchymal or ectopic crystal deposition, as seen in nephrocalcinosis or cystinosis, and ductal crystallization as seen in renal calculus disease. The crystals involved included not only calcium oxalate, but also aluminum, amino acids and proteins (cystine, hemoglobin, cryoglobulins, and immunoglobulins), purine metabolites (xanthine, hypoxanthine), and even lipids and their degradative enzymes (cholesterol, phospholipids, phospholipase, and fatty acids). The simultaneous occurrence of crystals in both kidneys and joints was found in some cases to result from the systemic deposition of an excess of a particular biological compound. However, of more interest, some renal deposits were shown to more selectively reflect the normal or abnormal function of the kidney in its secretory and excretory roles. This is particularly evident in the variety of arthritic states described in end-stage renal disease.