Carla L. Ellis

Pendrin localizes to the adrenal medulla and modulates catecholamine release

Pendrin (Slc26a4) is a Cl(-)/HCO3 (-) exchanger expressed in renal intercalated cells and mediates renal Cl(-) absorption. With pendrin gene ablation, blood pressure and vascular volume fall, which increases plasma renin concentration. However, serum aldosterone does not significantly increase in pendrin-null mice, suggesting that pendrin regulates adrenal zona glomerulosa aldosterone production. Therefore, we examined pendrin expression in the adrenal gland using PCR, immunoblots, and immunohistochemistry. Pendrin protein was detected in adrenal lysates from wild-type but not pendrin-null mice. However, immunohistochemistry and qPCR of microdissected adrenal zones showed that pendrin was expressed in the adrenal medulla, rather than in cortex. Within the adrenal medulla, pendrin localizes to both epinephrine- and norepinephrine-producing chromaffin cells. Therefore, we examined plasma catecholamine concentration and blood pressure in wild-type and pendrin-null mice under basal conditions and then after 5 and 20 min of immobilization stress. Under basal conditions, blood pressure was lower in the mutant than in the wild-type mice, although epinephrine and norepinephrine concentrations were similar. Catecholamine concentration and blood pressure increased markedly in both groups with stress. With 20 min of immobilization stress, epinephrine and norepinephrine concentrations increased more in pendrin-null than in wild-type mice, although stress produced a similar increase in blood pressure in both groups. We conclude that pendrin is expressed in the adrenal medulla, where it blunts stress-induced catecholamine release.

Renal Medullary and Cortical Correlates in Fibrosis, Epithelial Mass, Microvascularity, and Microanatomy Using Whole Slide Image Analysis Morphometry

Renal tubulointerstitial injury often leads to interstitial fibrosis and tubular atrophy (IF/TA). IF/TA is typically assessed in the renal cortex and can be objectively quantitated with computerized image analysis (IA). However, the human medulla accounts for a substantial proportion of the nephron; therefore, medullary scarring will have important cortical consequences and may parallel overall chronic renal injury. Trichrome, periodic acid–Schiff (PAS), and collagen III immunohistochemistry (IHC) were visually examined and quantitated on scanned whole slide images (WSIs) (N = 67 cases). When tuned to measure fibrosis, IA of trichrome and Trichrome-PAS (T-P) WSIs correlated for all anatomic compartments (among cortex, medulla, and entire tissue, r = 0.84 to 0.89, P all <0.0001); and collagen III deposition correlated between compartments (r = 0.69 to 0.89, P <0.0001 to 0.0002); however, trichrome and T-P measures did not correlate with collagen deposition, suggesting heterogeneous contributions to extracellular matrix deposition. Epithelial cell mass (EPCM) correlated between cortex and medulla when measured with cytokeratin IHC and with the trichrome red portion (r = 0.85 and 0.66, respectively, all P < 0.0001). Visual assessment also correlated between compartments for fibrosis and EPCM. Correlations were found between increasing medullary inner stripe (IS) width and fibrosis in all of the tissue and the medulla by trichrome morphometry (r = 0.56, P < 0.0001, and r = 0.48, P = 0.00008, respectively). Weak correlations were found between increasing IS width and decreasing visual assessment of all tissue EPCM. Microvessel density (MVD) and microvessel area (MVA) measured using a MVD algorithm applied to CD34 IHC correlated significantly between all compartments (r = 0.76 to 0.87 for MVD and 0.71 to 0.87 for MVA, P all < 0.0001). Overall, these findings demonstrate the interrelatedness of the cortex and medulla and the importance of considering the renal parenchyma as a whole.

Metastatic prostate adenocarcinoma to the penis: a series of 29 cases with predilection for ductal adenocarcinoma.

Twenty-nine men with metastatic prostate adenocarcinoma to the penis were identified at our institution between 1993 and 2013. Of the 29 patients, 19 had a prior history of adenocarcinoma of the prostate, and 8 of those had ductal features in the primary lesion. Sixteen of 29 revealed ductal features in the metastasis. Seven of the 8 cases with ductal features in the primary had ductal features in the penile metastasis. Seven penile metastases were proven to be of prostatic origin solely by immunohistochemistry. Three cases were originally misdiagnosed as urothelial carcinoma upon review of the penile lesion. Other variant morphologies in the metastases included sarcomatoid carcinoma, small cell carcinoma, and adenosquamous carcinoma. In summary, prostate carcinoma involving the penis displays ductal features considerably more often than prostate cancer in general. Features that can cause difficulty in recognizing metastatic prostate adenocarcinoma to the penis include the unusual anatomic site for prostate cancer, poor differentiation, an increased prevalence of variant morphology, a long interval from the primary lesion, and, in some cases, no documented history of a primary prostatic lesion. Immunohistochemical analysis should be performed to rule out prostate carcinoma in penile/penile urethral tumors with morphology that differs from typical squamous or urothelial carcinoma. Even in the setting of metastatic disease, there is a critical need for an accurate diagnosis so that the appropriate therapy can be initiated, symptomatic relief can be provided, and long-term survival achieved in some cases, while at the same time avoiding penectomy for a misdiagnosis of a primary penile cancer.

Questionable specificity of histologic findings in calcific uremic arteriolopathy

A variety of criteria exist for histopathologic diagnosis of calciphylaxis, also known as calcific uremic arteriolopathy but data on their specificity are limited. To assess this, histologic findings of 38 skin biopsies performed for a suspicion of calcific uremic arteriolopathy were compared with histologic findings in skin obtained from healthy margins of 43 amputations in patients with end-stage renal disease (ESRD) without evidence of calcific uremic arteriolopathy. Abnormalities in small arteries or arterioles were present in 35% of amputation specimens and 55% of skin biopsies, and among these only thrombosis but not calcification was significantly more prevalent in skin biopsies. The prevalence of extravascular calcification did not differ. Vascular lesions were more common in skin biopsies from patients with high clinical suspicion of calcific uremic arteriolopathy (81%), significantly driven by increases in both calcification and thrombosis, compared to amputations (35%). The combination of medial calcification and thrombosis was six-fold more prevalent in high-suspicion skin biopsies than in amputation specimens. The location of affected vessels did not differ. In two autopsy cases, some but not all findings of involved skin were also present in uninvolved skin. Thus, histopathologic findings historically associated with calcific uremic arteriolopathy can also occur in viable tissue from unaffected patients with ESRD, calling into question the specificity of individual histologic findings for calcific uremic arteriolopathy. However, the combination of medial calcification and thrombosis was rare in unaffected patients and may provide a higher degree of specificity.

Renal allograft granulomatous interstitial nephritis: observations of an uncommon injury pattern in 22 transplant recipients

Abstract Background: Granulomatous interstitial nephritis (GIN) is uncommon in native kidneys, and descriptions in allografts are few. We report clinical and pathologic findings in 22 allograft recipients with GIN identified in renal allograft biopsies and nephrectomies. Methods: Renal allografts with GIN were retrieved from the pathology files of two academic medical centers. Available clinical and pathologic data were compiled retrospectively for a 23-year period. Results: GIN was present in 23 specimens from 22 patients (15 males and 7 females) with allograft dysfunction [serum creatinine averaged 3.3 mg/dL (range 1.4–7.8)], at a mean age of 48 years (range 22–77). GIN was identified in 0.3% of biopsies at a mean of 552 days post transplantation (range 10–5898). GIN was due to viral (5), bacterial (5) and fungal (2) infections in 12 (54.5%), and drug exposure was the likely cause in 5 cases (22.7%). One had recurrent granulomatosis with polyangiitis. In 4 cases, no firm etiology of GIN was established. Of 18 patients with follow up data, 33.3% had a complete response to therapy, 44.5% had a partial response and 22.2% developed graft loss due to fungal and E. coli infections. All responders had graft survival for more than 1 year after diagnosis of GIN. Conclusions: Allograft GIN is associated with a spectrum of etiologic agents and was identified in 0.3% of biopsies. Graft failure occurred in 22% of this series, due to fungal and bacterial GIN; however, most had complete or partial dysfunction reversal and long–term graft survival after appropriate therapy.

Renal Hypertrophy in Liver Failure

NASH, nonalcoholic steatohepatitis. To the Editor: The relationship between kidney function and liver function has been investigated largely in the context of pathologic changes in advanced liver failure, and little is known about any physiologic responses to hepatic failure. Because both organs are responsible for clearing metabolic byproducts, there may be renal compensation for decreased hepatic clearance. This possibility is supported by the fact that both kidney size and glomerular filtration rate vary with other alterations in metabolic demand, such as changes in body size or protein intake. Our frequent finding of large kidneys during sonography in patients with end-stage liver disease supported the possibility that renal hypertrophy was occurring. This was investigated by measuring renal parenchymal volume (RPV) on computed tomography scans and examining autopsy findings in patients with or without end-stage liver disease and no clinical or radiologic evidence of intrinsic renal disease.

63-Year-Old Woman with Dysphonia, Dysphagia, and Sleep Apnea

An obese and hypertensive 63-year-old Caucasian woman presented with persistent and progressively worsening exertional dyspnea, occasionally accompanied by anginal chest pain as well as dysphonia, hoarseness, dysphagia, complaints of lower extremity weakness, and documented mild chronic L5-S1 denervation. Work-up revealed moderate obstructive ventilatory defect, borderline restrictive defect, and variable extrathoracic obstruction. Weakness and progressively poor quality of sleep characterized by sleep-disordered breathing, increased daytime somnolence, fatigue upon waking and increased snoring were added to her initial complaints. A sleep study established the diagnosis of severe obstructive sleep apnea. Treatment with continuous positive airway pressure (CPAP) produced significant improvement in her energy levels, more restful sleep and less fatigue, but her dyspnea worsened. A new cycle of cardiac and respiratory evaluation was positive for mild pulmonary hypertension and negative for myocardial ischemia and pulmonary fibrosis. Shortly after these last assessments, and two to three years after onset of symptoms, the patient died suddenly in her sleep. NEUROPATHOLOGY