Solitary Fibrous Tumor of the Kidney With Pure Round Cell Features: A Case Report With Review of Literature.

Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm known to occur at various soft tissue and visceral locations. Kidney is a rarely reported site for these tumors. Most of the SFTs described in the kidney exhibit a classical CD34-positive patternless spindle cell histology. Focal round cell morphology is seldom reported. Herein, we describe a 48-year-old male patient with renal SFT. This tumor had pure round cell morphology with a CD34-/STAT6+ immunophenotype. Fluorescent in situ hybridization and a multiplexed sequencing assay performed on an Illumina® HiSeq 4000 platform revealed NAB2 and STAT6 gene rearrangement. Renal tumors with round cell morphology are diagnostically challenging and SFT is not often considered in the differential diagnosis of a round cell tumor of the kidney. Moreover, a CD34-negative profile can be rather confounding while diagnosing such lesions. In such scenarios, a strong nuclear STAT6 immunostaining is extremely helpful in clinching the diagnosis. SFT should always be considered in the differential diagnosis of round cell tumors of the kidney due to significant diagnostic and therapeutic implications.

Reporting Trends, Practices, and Resource Utilization in Neuroendocrine Tumors of the Prostate Gland: A Survey among Thirty-Nine Genitourinary Pathologists.

Background. Neuroendocrine differentiation in the prostate gland ranges from clinically insignificant neuroendocrine differentiation detected with markers in an otherwise conventional prostatic adenocarcinoma to a lethal high-grade small/large cell neuroendocrine carcinoma. The concept of neuroendocrine differentiation in prostatic adenocarcinoma has gained considerable importance due to its prognostic and therapeutic ramifications and pathologists play a pivotal role in its recognition. However, its awareness, reporting, and resource utilization practice patterns among pathologists are largely unknown. Methods. Representative examples of different spectrums of neuroendocrine differentiation along with a detailed questionnaire were shared among 39 urologic pathologists using the survey monkey software. Participants were specifically questioned about the use and awareness of the 2016 WHO classification of neuroendocrine tumors of the prostate, understanding of the clinical significance of each entity, and use of different immunohistochemical (IHC) markers. De-identified respondent data were analyzed. Results. A vast majority (90%) of the participants utilize IHC markers to confirm the diagnosis of small cell neuroendocrine carcinoma. A majority (87%) of the respondents were in agreement regarding the utilization of type of IHC markers for small cell neuroendocrine carcinoma for which 85% of the pathologists agreed that determination of the site of origin of a high-grade neuroendocrine carcinoma is not critical, as these are treated similarly. In the setting of mixed carcinomas, 62% of respondents indicated that they provide quantification and grading of the acinar component. There were varied responses regarding the prognostic implication of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and for Paneth cell-like differentiation. The classification of large cell neuroendocrine carcinoma was highly varied, with only 38% agreement in the illustrated case. Finally, despite the recommendation not to perform neuroendocrine markers in the absence of morphologic evidence of neuroendocrine differentiation, 62% would routinely utilize IHC in the work-up of a Gleason score 5 + 5 = 10 acinar adenocarcinoma and its differentiation from high-grade neuroendocrine carcinoma. Conclusion. There is a disparity in the practice utilization patterns among the urologic pathologists with regard to diagnosing high-grade neuroendocrine carcinoma and in understanding the clinical significance of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and Paneth cell-like neuroendocrine differentiation. There seems to have a trend towards overutilization of IHC to determine neuroendocrine differentiation in the absence of neuroendocrine features on morphology. The survey results suggest a need for further refinement and development of standardized guidelines for the classification and reporting of neuroendocrine differentiation in the prostate gland.

Collapsing Glomerulopathy: A Single Centre Clinicopathologic Study of Seven Years.

INTRODUCTION: Collapsing Glomerulopathy (CG) is recognized as distinct pattern of proliferative parenchymal injury with poor response to empirical therapy. AIM: A single center retrospective study was carried out to find out clinicopathological features of idiopathic CG. MATERIALS AND METHODS: A total of 3335 native renal biopsies were analyzed retrospectively which were performed from 2008 to 2014 with emphasis on clinicopathological correlation and histopathological presentation. RESULTS: Idiopathic CG constituted 0.75% incidence (25 out of 3335 biopsies) of all biopsies, adults constituting major study part with 88%. The duration of the symptoms at the time of biopsy was 34.12±26.09 days and 35±22.91 days respectively in adults and children. Hypertension was noted in 9(40.9%) and oliguria in 8(36.4%) in adults. Urinalysis revealed microscopic haematuria 12(54.5%) in adults. Nephrotic range proteinuria was reported in 10 (45.5%) adult patients. Glomerular collapse with hyperplasia/ hypertrophy of podocytes was seen in 4.54±3.11 glomeruli. Tubular microcystic dilation was seen in 16(64%) patients. Tubular atrophy involving mild (t1) in 15(60%), moderate (t2) in 4(16%) and severe (t3) in 6(24%) patients. Interstitial fibrosis was mild (i1) in 17(68%), moderate (i2) in 2(8%) and severe (i3) in 6(24%) patients. CONCLUSION: Idiopathic CG is a morphological pattern of grave podocyte injury with poor prognosis. However, there are chances of remission/ recovery if the tubular atrophy and interstitial fibrosis are of grades ≤ t1 i1.

Pediatric Renal Biopsies in India: A Single-Centre Experience of Six Years.

BACKGROUND: Renal biopsy is a well-established diagnostic modality for the assessment of kidney diseases in children. It can provide diagnostic precision and prognostic value and guide in therapeutic options for many renal diseases. OBJECTIVES: This report describes the indication, histopathological patterns, and epidemiology of renal diseases in children in India. PATIENTS AND METHODS: This is a single-center study on renal biopsies performed between January 2008 and December 2013 in 346 children (age ≤ 14 years). RESULTS: Eleven (3.17%) biopsies were inadequate, and 335 biopsies were considered for analysis. The mean age was 7.91 ± 3.04 years with a predominance of males (68.1%). Nephrotic syndrome (46.2%) was the most common indication, followed by urinary abnormality (41.19%), acute nephritic syndrome (10.74%), and chronic renal failure (1.79 %). Primary glomerulonephritis (GN) was predominant (81.79%), and secondary GN constituted 16.12% of the biopsies. Primary GN included mesangial proliferative GN (MePGN), IgM nephropathy, focal segmental glomerulosclerosis, minimal change disease, IgA nephropathy, membranoproliferative GN, membranous nephropathy, crescentic GN, and post-infectious GN. Secondary GN revealed lupus nephritis, hemolytic uremic syndrome, amyloidosis, and hypertensive nephropathy. Tubulointerstitial nephritis was observed in 2.08%. The most common histological pattern of primary GN was MePGN (20%) and in secondary GN it was lupus nephritis (7.76%). CONCLUSIONS: The present study provides data on the epidemiology of renal diseases in children in India and will be helpful for developing a national registry and devising therapeutic guidelines.