Shree G. Sharma

The Modern Spectrum of Renal Biopsy Findings in Patients with Diabetes

BACKGROUND AND OBJECTIVES Renal biopsies performed in diabetic patients are increasing in number and complexity. This study sought to determine the usefulness of renal biopsy in patients with diabetes and the predictability of diagnosing diabetic nephropathy (DN) versus nondiabetic renal disease (NDRD) from clinical and laboratory data. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS To assess modern trends, a retrospective study was performed of clinical-pathologic findings in all patients with diabetes who had a biopsy in 2011. Among 2642 native kidney biopsies, 620 (23.5%) were from patients with diabetes. RESULTS The cohort included 371 men (60.7%) aged a median (interquartile range) 62 years (52-69) with 10-year (5-15) duration of diabetes mellitus (DM). Median serum creatinine was 2.5 mg/dl (1.6-4.4), and 52% of patients had stage 4-5 CKD. On biopsy, 37% of patients had DN alone, 36% had NDRD alone, and 27% had DN plus NDRD. In NDRD alone, FSGS (22%), hypertensive nephrosclerosis (18%), acute tubular necrosis (ATN) (17%), IgA nephropathy (11%), membranous GN (8%), and pauci-immune GN (7%) comprised 80% of diagnoses, compared with ATN (43%), hypertensive nephrosclerosis (19%), FSGS (13%), and IgA nephropathy (7%) for DN plus NDRD. In multivariate analyses, longer duration of DM was associated with a greater likelihood of DN and a lower likelihood of NDRD: each added year of DM reduced the odds of NDRD by 5% (odds ratio, 0.95; 95% confidence interval, 0.91 to 0.98; P=0.004). DM duration ≥ 12 years was the best predictor (58% sensitivity, 73% specificity) of DN alone. CONCLUSIONS Approximately one-quarter of all renal biopsies are performed in patients with DM. Judicious use of renal biopsy has uncovered NDRD alone or superimposed on DN in the majority of such biopsies. ATN is emerging as an important category of NDRD, which has not been reported previously.

BRAF Mutation Testing in Colorectal Cancer

Colorectal cancer is the second most common cause of cancer death in the United States. Understanding the biochemical pathways underlying carcinogenesis has paved the way for more effective treatments and better outcomes. BRAF mutation testing has a role in (1) differentiating sporadic colorectal cancer from Lynch syndrome, (2) identifying cancers lacking BRAF mutation that are more likely to respond to epidermal growth factor receptor inhibitor therapy, and (3) conferring worse prognosis in colorectal cancer that is microsatellite stable. Several analytic methods are available to reliably detect BRAF mutations. Real-time polymerase chain reaction identifies the most common BRAF mutation, V600E, in frozen or paraffin-embedded colorectal cancer tissue. Traditional DNA sequencing and the somewhat more-sensitive pyrosequencing method can detect multiple alternative BRAF mutations that are predicted to constitutively activate signaling through the MAPK pathway, promoting tumor growth and survival. Pathologists play an important role in assay validation as well as in consulting with clinicians about indications for testing, ensuring quality of testing, and interpreting results in conjunction with other clinicopathologic factors important in the management of affected patients.

Cardiac Hypertrophy During Hypercholesterolemia and Its Amelioration With Rosuvastatin and Amlodipine

Hypercholesterolemia is a common accompaniment of atherosclerosis and may be associated with cardiac hypertrophy. To define the mechanistic basis of cardiac hypertrophy in hypercholesterolemia, we fed low-density lipoprotein receptor knockout (LDLR KO) mice regular diet or high cholesterol (HC) diet for 26 weeks. There was clear evidence of cardiomyocyte hypertrophy and collagen deposition in the hearts of LDLR KO mice fed with HC diet, confirmed by histopathology (hematoxylin and eosin and Picrosirius staining) and upregulation of genes for brain natriuretic peptide, α-tubulin, transforming growth factor β1, and connective tissue growth factor (CTGF). These changes were independent of change in blood pressure. The hypercholesterolemic mice hearts showed an upregulation of LOX-1, an oxidized low-density lipoprotein receptor, and angiotensin II type 1 receptor (AT1R) at messenger RNA level. In addition, there was a marked upregulation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and nuclear factor κB (NF-κB) messenger RNA, indicating overexpression of markers of oxidant stress. A separate group of LDLR KO mice were fed HC diet along with a potent 3-hydroxy-3-methylglutarylcoenzyme A reductase inhibitor rosuvastatin or a dihydropyridine calcium channel blocker amlodipine. Administration of rosuvastatin or amlodipine reduced the overexpression of genes for LOX-1 and AT1R and associated NADPH oxidase and NF-κB. These phenomena were associated with a marked decrease in cardiomyocyte hypertrophy and collagen deposits in and around the cardiomyocytes. In conclusion, this study provides evidence of cardiac hypertrophy and fibrosis in hypercholesterolemia independent of blood pressure change LOX-1 and AT1R act as possible signals for oxidant stress leading to alterations in cardiac structure during hypercholesterolemia. Most importantly, rosuvastatin and amlodipine ameliorate cardiomyocyte hypertrophy and fibrosis.

Endothelin-1 upregulation mediates aging-related cardiac fibrosis

Endothelin-1 (ET-1) plays a major role in regulating myocardial fibrosis in several pathological conditions, such as hypertension and diabetes. Aging is an independent risk factor for myocardial fibrosis. We hypothesized that ET-1 upregulation may be a basis of enhanced collagen synthesis in the senescent fibroblasts resulting in cardiac fibrosis with aging. To examine this hypothesis, we cultured mouse cardiac fibroblasts to passage-30 (P30). β-Galactosidase activity and several other aging markers were markedly increased in P30 (vs. P3) fibroblasts, indicating that these cells were indeed undergoing senescence. Importantly, ET-1 expression was markedly upregulated in P30 (vs. P3) fibroblasts. Of note, estrogen receptor-α (ER-α), an important negative regulator of ET-1, was downregulated in P30 fibroblasts. We also studied aged (130-weeks old, female) mice hearts, and observed that ET-1 was upregulated and ER-α was downregulated in these hearts (vs. 6-week old mice hearts, female). Similar observations were made in the fibroblasts isolated from aged mice hearts. ET-1 upregulation with aging was also seen in ≈70-year old (vs. ≈30-year old) human heart sections. In concert with ET-1 upregulation, the expression of fibronectin and collagens was found to be markedly increased in P30 cardiac fibroblasts in culture, fibroblasts isolated from the aged mice hearts, and in aged human hearts. Interestingly, inhibition of ET-1 in the senescent P30 fibroblasts by 2 different strategies (the use of siRNA and the use of endothelin converting enzyme inhibitors) markedly suppressed expression of fibrosis signals. Further, treatment with synthetic ET-1 enhanced fibronectin and collagen expression in P3 cardiac fibroblasts. These observations in mice and human hearts suggest that aging-related cardiac fibrosis is, at least partially, dependent on the upregulation of ET-1.

The Utility of Pax-2 and Renal Cell Carcinoma Marker Immunohistochemistry in Distinguishing Papillary Renal Cell Carcinoma From Nonrenal Cell Neoplasms With Papillary Features

PAX-2, a homeogene expressed during kidney development, has been studied as a marker of renal origin in both primary and metastatic clear cell renal cell carcinoma (RCC), but not in papillary neoplasms or in comparison with RCC marker (RCCma). We studied immunohistochemical expression of PAX-2 and RCCma in 24 papillary RCC (PRCC) and 66 nonrenal cell papillary neoplasms (NRCPN) from a variety of organs. Of the PRCC, 16/24 (67%) were positive for PAX-2; 23/24 (96%) were positive for RCCma. Of the NRCPN, 9/66 (14%) is positive for PAX-2 [4/10 (40%) ovarian papillary serous carcinomas, 5/9 (56%) uterine papillary serous carcinomas]; RCCma was positive in 28/66 (42%), including 9/9 (100%) papillary thyroid carcinomas, 8/10 (80%) ovarian papillary serous carcinomas, 4/9 (44%) uterine papillary serous carcinomas, 1/10 (10%) papillary urothelial carcinomas, 1/2 (50%) intraductal papillary mucinous carcinomas of the pancreas, 3/3 (100%) choroid plexus papillomas, 1/1 (100%) pituitary adenoma with papillary features, and 1/2 (50%) lung adenocarcinomas with papillary features. The sensitivity of PAX-2+/RCCma+ immunophenotype for PRCC was 58% with a specificity of 54%. There is significant overlap between the expressions of these markers in PRCC and NRCPN; however, the positivity of RCCma and/or PAX-2 is 100% sensitive for PRCC and may prove useful in the initial work up of metastases of unknown primary. PAX-2 and RCCma immunohistochemistry should be interpreted with caution in papillary neoplasms, with particular attention to the possibility of ovarian and uterine papillary serous carcinomas, which can express both PAX-2 and RCCma.

Intrapancreatic Accessory Spleen: Investigative Dilemmas and Role of EUS-Guided FNA for Diagnostic Confirmation

CONTEXT We submit a case of intrapancreatic accessory spleen. CASE REPORT A 33-year-old patient with history of dyspepsia underwent imaging studies suggestive of a neuroendocrine tumor. After referral to our institute, endoscopic ultrasound guided fine needle aspiration (EUS-FNA) confirmed diagnosis as intrapancreatic accessory spleen. DISCUSSION An accessory spleen may develop from estranged mesenchymal cells due to fusion failure of the splenic anlage. The prevalence of an accessory spleen is 10-30% with 80% of them present at the splenic hilum and 17% in the pancreatic tail. Intrapancreatic accessory spleen is commonly misdiagnosed as a pancreatic tumor. Since, the differential diagnosis includes pancreatic neuroendocrine tumors, additional investigation with EUS-FNA should be considered when radiological diagnosis is not definitive. CONCLUSION For diagnosis of intrapancreatic accessory spleen, radiographic imaging is useful, but lacks specificity without tissue diagnosis. Diagnosis can be safely and reliably established with EUS-FNA, leading to a benign prognosis and avoidance of unnecessary surgical intervention.

Extensive Extramedullary Disease Involving the Colon in Multiple Myeloma: A Case Report and Review of Literature

IntroductionOrgan involvement in multiple myeloma (MM) is characterized by infiltrative disease or by a myelomatous mass known as a plasmacytoma. We present a patient with MM who had extensive extramedullary involvement of the colon and a review of the literature on colon plasmacytomas.Case reportA 57-year-old male with MM presented with disease relapse in 2007, workup showing biopsy confirmed left perinephric extra-medullary disease involving the adjacent colon. Positron emission-tomography (PET) exhibited intense pan-colonic fluoro-deoxyglucose (FDG) uptake and computed-tomography confirmed extensive infiltrating soft tissue thickening in the ascending, transverse, and descending colon representing plasmacytomas. The patient underwent an autologous hematopoietic stem cell transplantation after conditioning with high-dose melphalan. Restaging PET-scan showed complete resolution of colonic extra-medullary plasmacytomas. Extramedullary plasmacytomas (EMP) are rare and constitute 4% of all plasma cell tumors.Discussion and ConclusionColonic plasmacytoma is an extremely rare site, with fewer than 25 cases reported in the literature. Colonic plasmacytomas have different presentations depending on the size and location. Treatment options for primary EMPs include surgical resection, radiotherapy, and chemotherapy. The primary treatment option for secondary EMP is systemic chemotherapy. This rare pan-colonic plasmacytoma, as a part of extramedullary myeloma, showed an impressive response to chemotherapy.

Proflavine Hemisulfate as a Fluorescent Contrast Agent for Point-of-Care Cytology

Proflavine hemisulfate, an acridine-derived fluorescent dye, can be used as a rapid stain for cytologic examination of biological specimens. Proflavine fluorescently stains cell nuclei and cytoplasmic structures, owing to its small amphipathic structure and ability to intercalate DNA. In this manuscript, we demonstrated the use of proflavine as a rapid cytologic dye on a number of specimens, including normal exfoliated oral squamous cells, cultured human oral squamous carcinoma cells, and leukocytes derived from whole blood specimens using a custom-built, portable, LED-illuminated fluorescence microscope. No incubation time was needed after suspending cells in 0.01% (w/v) proflavine diluted in saline. Images of proflavine stained oral cells had clearly visible nuclei as well as granular cytoplasm, while stained leukocytes exhibited bright nuclei, and highlighted the multilobar nature of nuclei in neutrophils. We also demonstrated the utility of quantitative analysis of digital images of proflavine stained cells, which can be used to detect significant morphological differences between different cell types. Proflavine stained oral cells have well-defined nuclei and cell membranes which allowed for quantitative analysis of nuclear to cytoplasmic ratios, as well as image texture analysis to extract quantitative image features.

Light Chain Proximal Tubulopathy: Expanding the Pathologic Spectrum with and without Deposition of Crystalline Inclusions

Light chain proximal tubulopathy (LCPT) is an uncommon form of renal disease associated with dysproteinemias. It is characterized by intracytoplasmic deposition of crystallized mostly kappa monoclonal light chains in proximal tubules (PTs). Crystals are located within lysosomes by electron microscopy (EM). Rare lambda LCPT cases without crystals by EM were described. Retrospectively, we reviewed clinical, light microscopic (LM), immunofluorescence (IF), and EM findings in 9 cases) (8 males, 1 female; mean age 57 years (38–81)) with multiple myeloma. LM showed abundant cytoplasmic droplets in PT cells in all cases. Droplets were also present in the podocytes, endothelial and parietal cells in one case. IF revealed staining of crystals with kappa in 3 and lambda in 6. EM showed electron dense rectangular, rhomboid, or needle shaped crystals in PT cells in 3 cases (33%), one of which had crystals in podocytes and interstitial cells. Six lambda LCPT cases showed no crystals by EM (67%). This may reflect differences in the physicochemical properties of light chains. The mechanisms of crystal accumulation in these cells and the significance of this finding are unknown.

PSEUDOMELANOSIS DUODENI: A RARE FINDING FROM UPPER ENDOSCOPY

Dear Editor, A 65-year-old black woman with a history of end-stage renal disease (requiring hemodialysis), diabetes mellitus and hypertension, underwent endoscopy for work-up of anemia. Upper endoscopy revealed an abnormal dark pigmentation in the duodenal bulb and the second portion of the duodenum. Biopsies of the duodenum revealed a black granular pigment within the tips of villi. The diagnosis of pseudomelanosis duodeni was made on the basis of clinical, endoscopic and histological findings. Pseduomelanosis duodeni is an extremely rare condition not associated with a duodenal malignancy. To an endoscopist, the typical finding is a flat hyperpigmented brownish-black speckled duodenal mucosa. Histology demonstrates the accumulation of a dark pigment within the macrophages of the lamina propria. There are no cases where endoscopic hyperpigmentation was not supported by histological evidence of pseudomelanosis duodeni. The present case is being submitted for its classical endoscopy and histological findings. A 65-year-old black woman with a history of end-stage renal disease (requiring hemodialysis), diabetes mellitus, hypertension, and hypothyroidism was referred to our clinic for anemia. The patient was on multiple medications, including zolpidem, aspirin, clonidine, hydralazine, insulin, levothyroxine, and metoprolol. Upper endoscopy revealed an abnormal dark pigmentation in the duodenal bulb and the second portion of the duodenum (Fig. 1). Biopsies of the duodenum were taken, and histology revealed a black granular pigment within the tips of villi, which was negative for iron (Fig. 2). The diagnosis of pseudomelanosis duodeni was made on the basis of clinical, endoscopic and histological findings. Pseduomelanosis duodeni is an extremely rare, benign condition first described by Bisordi and Kleinman in 1976. To an endoscopist, the typical finding is a flat hyperpigmented brownish-black speckled duodenal mucosa. Histology unequivocally demonstrates the accumulation of a dark pigment within the macrophages of the lamina propria.There are no cases where endoscopic hyperpigmentation was not supported by histological evidence of pseudomelanosis duodeni; however, there are cases in which biopsies of a normal-appearing duodenum have disclosed pseudomelanosis duodeni histologically. Review of the literature shows that pseudomelanosis duodeni usually occurs in women older than 60 years of age and rarely occurs in a setting other than chronic renal failure, arterial hypertension, and/or diabetes mellitus. Consequently, certain medications (e.g. ferrous sulfate, hydralazine, propanolol, hydrochlorothiazide, furosemide) have been associated with this condition. The brownish-black pigment is mainly ferrous sulfide with small amounts of other elements. The source and pathogenesis of pigment deposition exclusively in the duodenal mucosa and the prognostic implications of pseudomelanosis duodeni are unknown. There has been no documented fibrosis, duodenitis, stricture formation or ulceration described in the literature. Hence, the significance of such finding, prognosis, and guidelines regarding endoscopic surveillance have not been determined.