Nephrogenic adenoma identified on urine cytology using PAX-2 immunostaining

Clear cell lesions in pathology: Histomorphologic approach to diagnosis

There has been remarkable progress in the field of surgical pathology; however, histomorphology has remained the most important and essential tool of the surgical pathologist in everyday practice till now. It is surprising that the hematoxylin-eosin (H and E) stain, introduced more than a century ago, has still remained the gold standard stain for histological examination and diagnosis of human diseases. Besides different findings or clues observed in histopathology sections like inclusions, granules, grooving, globules, halo, or clearing, which would enable the pathologist to provide a precise and accurate diagnosis; observation of clear cells is one of the important findings and clue for reporting. It may also sometimes lead to difficulties and delays in establishing the diagnosis. It can be focal or extensive and primary or rarely it may be secondary. Clear cell changes may be observed in many non-neoplastic, benign, or malignant tumors of diverse origin. Clear cell tumors contain a preponderance of clear cells. It can be seen in almost all the organs of human body and can be classified according to location or biological behavior. Commonly seen clear-cell tumors are usually malignant and common organs involved are female genital tract, urogenital tract, head and neck areas, central nervous system, skin, and rarely in bone and soft tissues. For approach to clear cell lesions, one has to decide if the change is artifactual, a mimic of clear cell tumors, or a clear cell tumor in reality. Once the mimics and artifactual/degenerative changes have been ruled out, a tumor either primarily of clear cell origin or showing secondary change has to be decided. The tumor next is to be diagnosed as benign/malignant and epithelial/mesenchymal based on morphology.

Common and uncommon features of nephrogenic adenoma revisited

Nephrogenic adenoma is a common diagnosis in urological pathology that may be challenging for general pathologists. Due to its polymorphic appearance under the microscope, some cases can be misdiagnosed as malignancy and then unnecessarily overtreated. Aside from the typical tubules, cysts and papillae, nephrogenic adenoma may display a broad spectrum of histologic appearances and locations, some of them atypical or unexpected. These unusual and concerning features will have special consideration in this description. The goal of the review is to increase awareness of general pathologists of the varied histology of nephrogenic adenoma.

Novel round cells in urine sediment and their clinical implications

BACKGROUND

Voided urine contains a variety of cells from the kidney and urinary tract and urinalysis provides us various information by investigating cellular components. We investigated urine sediment from renal impaired patients.

RESULTS

We found 'round cell' to be distinct from known cells in sediment and is close to proximal convoluted tubule-derived cells based on morphology and molecular marker expression (GGT1 but not podocalyxin). Also it was positive for undifferentiated cell markers, including PAX2, WT1, OSR1, and SIX2. They were observed in end-stage renal failure patients and the number of cells was correlated with the severity of chronic kidney disease. A prospective analysis revealed that patients who had more round cells were more likely to require hemodialysis within a year.

CONCLUSION

Round cells are a novel marker that can be used to predict the need for hemodialysis.

Can We Identify Nephrogenic Adenoma in Urine Cytology Specimens? A Study Evaluating Previously Described Cytomorphologic Features in Correlation With PAX8 Immunohistochemical Staining Results

OBJECTIVES

The aim of this study is to determine if the diagnosis of nephrogenic adenoma (NA) can be made on cytologic criteria alone and if pair box gene transcription factor 8 (PAX8) is useful in the diagnosis of NA in daily cytology practice.

METHODS

Cytologic features of NA previously described in a literature were used to identify NA cells in urinary specimens. Subsequently, all cytology and corresponding biopsy specimens were stained with the PAX8 immunohistochemistry stain. The stains were examined; the results were tabulated.

RESULTS

A total of 44 specimens were reviewed (35 with corresponding biopsy specimens diagnosed as NA and nine negative for NA diagnosis on corresponding biopsy specimens). Of them, 14 demonstrated features previously described as NA. None of atypical cells that were morphologically suspicious for NA showed positive staining, whereas all of the corresponding biopsy sections demonstrated nuclear PAX8 positivity. Only rare lymphocytes present in cytology specimens showed nuclear staining with PAX8.

CONCLUSIONS

Assuming that the results of the PAX8 stain performed are accurate at least in most cases, as suggested by the presence of internal positive controls, our study shows that the previously described cytologic features of NA cannot be used as diagnostic criteria, since they are not characteristic for this entity.

Ubiquilin2 as a novel marker for detection of urothelial carcinoma cells in urine

BACKGROUND

Ubiquilin 2 (UBQLN2), an ubiquitin-related protein, is strongly expressed in urothelial carcinoma cells, in contrast to no or less expression in non-neoplastic cells; it protects cancer cells from reactive oxygen species (ROS)-induced cytotoxicity. In this study, we investigated whether UBQLN2 immunostaining, using liquid-based cytology sample could improve the accuracy of cytological urine diagnosis.

METHODS

Two-hundred and forty-five urinary samples, including 143 negative controls and 102 urothelial carcinomas, consisting of 42 low-grade and 60 high-grade urothelial carcinomas, were used for immunocytochemical analysis of UBQLN2.

RESULTS

Urothelial carcinoma cells were positive for UBQLN2-staining, while non-neoplastic cells, including renal tubular cells and degenerative atypical cells, were negative. Interestingly, percentage of nuclear stain immunopositive for UBQLN2 was significantly higher in carcinoma cells with high grade/invasive phenotype than in those with low grade/noninvasive phenotype. UBQLN2 immunostaining had an overall sensitivity of 87.6%, specificity of 98.6%, positive predictive value of 97.8% and negative predictive value of 92.8% for the detection of urothelial carcinoma.

CONCLUSIONS

UBQLN2 immunostaining is a practical test for urine cytology, even in samples with few cells, with slight atypia or severe degenerative changes. In addition, it allows prediction of tumor grade and stage by examining the cellular localization of UBQLN2.

Nephrogenic Adenoma of the Urinary Bladder: A Review of the Literature

Background. Nephrogenic adenoma of the urinary bladder (NAUB) is a rare lesion associated with nonspecific symptoms and could inadvertently be misdiagnosed. Aim. To review the literature. Methods. Various internet search engines were used. Results. NAUB is a benign tubular and papillary lesion of the bladder, is more common in men and adults, and has been associated with chronic inflammation/irritation, previous bladder surgery, diverticula, renal transplantation, and intravesical BCG; recurrences and malignant transformations have been reported. Differential diagnoses include clear cell adenocarcinoma, endocervicosis, papillary urothelial carcinoma, prostatic adenocarcinoma of bladder, and nested variant of urothelial carcinoma; most NAUBs have both surface papillary and submucosal tubular components; both the papillae and tubules tend to be lined by a single layer of mitotically inactive bland cells which have pale to clear cytoplasm. Diagnosis may be established by using immunohistochemistry (positive staining with racemase; PAX2; keratins stain positive with fibromyxoid variant), electron microscopy, DNA analysis, and cytological studies. Treatment. Endoscopic resection is the treatment but recurrences including sporadic malignant transformation have been reported. Conclusions. There is no consensus on best treatment. A multicentre study is required to identify the treatment that would reduce the recurrence rate, taking into consideration that intravesical BCG is associated with NAUB.

Nephrogenic adenoma of the urinary tract: clinical, histological, and immunohistochemical characteristics

Nephrogenic adenoma is a benign condition of the urinary tract resulting from the displacement and seeding of renal tubular cells from the renal pelvis to the urethra. A retrospective series of 134 cases collected from four hospitals in three different countries was analyzed in this study. Recorded clinical data included age and sex, topography, urological antecedents, coexistent lesions, and follow-up. Cytonuclear and architectural features were reviewed, and PAX-8, p63, PSMA, S100A1, CEA, EMA, CD117, cannabinoid receptor CB1, AMACR, E-cadherin, and CD10 antibodies were included in an immunohistochemical panel. Males predominated (105 M/29 F) with an average age of 66 years (range, 14-96). Urothelial carcinoma was the most frequent clinical antecedent (43.2 %) and also the most common coexisting lesion (14 %). Tubular architecture was the most frequent pattern detected (40 %) although most cases showed a mixed pattern (45.5 %). Deep infiltrative growth into the muscularis propria occurred in two cases. EMA and PAX-8 were expressed in 100 % of nephrogenic adenomas, while E-cadherin reactivity was observed in 66.6 % of cases, cannabinoid receptor CB1 in 25 %, CD10 in 13.6 %, CD117 in 4.1 %, and AMACR in 2.7 %. For the rest of the antigens, no reactivity was found. The average time lapse between the pathological antecedent and the discovery of a nephrogenic adenoma was 32 months. We conclude that nephrogenic adenoma displays a broad spectrum of histological features that may mimic malignancy. In our experience, CB1 immunostaining adds a further argument in favor of a renal origin of this lesion. The combination of PAX-8+, p63-, and EMA + distinguishes nephrogenic adenoma from urothelial and prostate carcinoma, its most frequent malignant look-alikes.

Flat pattern of nephrogenic adenoma: previously unrecognized pattern unveiled using PAX2 and PAX8 immunohistochemistry

Nephrogenic adenoma is a benign lesion of the urinary tract, particularly the urinary bladder. It is a gross and microscopic mimicker of urothelial neoplasm or metastatic carcinoma. Several histological patterns (tubular, tubulocystic, polypoid, papillary, fibromyxoid) have been recognized, but a flat pattern has not been described. Histologically, nephrogenic adenoma consists of tubules, cysts or papillae lined by flat to polygonal cells with frequent hobnail appearance. The stroma is often edematous or has a granulation tissue-like appearance with acute or chronic inflammation. By immunohistochemistry, nephrogenic adenomas are positive for renal epithelial markers CK7, CD10 and alpha-methylacyl-coenzyme A racemase, and negative for bladder urothelium or prostate markers. Recent studies have shown that nephrogenic adenomas are positive for PAX2 and PAX8. We encountered an interesting case of tubular nephrogenic adenoma with adjacent areas suspicious of flat urothelial atypia. Immunohistochemistry for PAX2 and PAX8 were positive in these areas, unveiling a flat pattern of nephrogenic adenoma. This case prompted us to study 15 cases of nephrogenic adenoma to determine additional instances of flat pattern and to assess the value of PAX2 and PAX8 immunoreactivity to diagnose nephrogenic adenoma. PAX2 and PAX8 immunostaining was positive in 14/15 and 15/15 cases, respectively. The flat pattern was present at least focally adjacent to tubular, polypoid and papillary areas, in 8/15 cases of nephrogenic adenoma. In conclusion, the flat pattern is a common finding in nephrogenic adenomas, but easily under recognized by morphologic examination and may be confused with flat urothelial lesions with atypia. Immunostains for PAX2 and PAX8 are useful in the detection of nephrogenic adenomas and particularly unveil those nephrogenic adenomas with flat pattern.

PAX Genes in Cancer; Friends or Foes?

PAX genes have been shown to be critically required for the development of specific tissues and organs during embryogenesis. In addition, PAX genes are expressed in a handful of adult tissues where they are thought to play important roles, usually different from those in embryogenesis. A common theme in adult tissues is a requirement for PAX gene expression in adult stem cell maintenance or tissue regeneration. The connections between adult stem cell PAX gene expression and cancer are intriguing, and the literature is replete with examples of PAX gene expression in either situation. Here we systematically review the literature and present an overview of postnatal PAX gene expression in normal and cancerous tissue. We discuss the potential link between PAX gene expression in adult tissue and cancer. In addition, we discuss whether persistent PAX gene expression in cancer is favorable or unfavorable.

Pax genes in embryogenesis and oncogenesis

The paired box genes are a family of nine developmental control genes, which in human beings (PAX) and mice (Pax) encode nuclear transcription factors. The temporal and spatial expressions of these highly conserved genes are tightly regulated during foetal development including organogenesis. PAY/Paxgenes are switched off during the terminal differentiation of most structures. Specific mutations within a number of PAX/Pax genes lead to developmental abnormalities in both human beings and mice. Mutation in PAX3 causes Waardenburg syndrome, and craniofacial-deafness-hand syndrome. The Splotch phenotype in mouse exhibits defects in neural crest derivatives such as, pigment cells, sympathetic ganglia and cardiac neural crest-derived structures. The PAX family also plays key roles in several human malignancies. In particular, PAX3 is involved in rhabdomyosarcoma and tumours of neural crest origin, including melanoma and neuroblastoma. This review critically evaluates the roles of PAX/Pax in oncogenesis. It especially highlights recent advances in knowledge of how their genetic alterations directly interfere in the transcriptional networks that regulate cell differentiation, proliferation, migration and survival and may contribute to oncogenesis.