SDH-deficient renal cell carcinoma – clinical,pathologic and genetic correlates: a case report

Background

Succinate dehydrogenase (SDH)- deficient renal cell carcinoma (RCC) is a newly identified rare subtype of RCC, having only gained acceptance from the World Health Organization in 2016. To the best of our knowledge, there are only 55 reported cases worldwide. Here, we report a new case of SDH-deficient RCC.

Case presentation

A 49-year-old male patient was incidentally found to have a large right renal mass. He had no personal or family history of paragangliomas (PGL), pheochromocytomas (PC), or gastrointestinal stromal tumors (GIST). The neoplasm was unilateral and unifocal. He underwent an open partial nephrectomy. Detailed pathological analysis was conducted to confirm the diagnosis. Genetic testing revealed a pathogenic mutation in the SDHB gene. He has been followed for 24?months now and has remained well without any evidence of local or distant recurrence. In this report we describe our experience with this diagnosis and review the relevant clinical, pathological, and genetic features.

Conclusions

Without the identification of SDHB deficiency, this patient’s personal and familial predisposition to PC, PGL, GIST and metachronous RCCs may have gone undetected despite his RCC diagnosis. When faced with an eosinophilic RCC, pathologists should routinely search for vacuoles or flocculent cytoplasmic inclusions. When these are present, or in cases of difficult eosinophilic renal tumors, staining for SDHB is recommended. For tumours without adverse pathologic features (i.e. high nuclear grade, coagulative necrosis, or sarcomatoid differentiation) excision alone may be a reasonable option, with the addition of regular surveillance for PC and PGLs in those found to harbor germline SDH mutations.

     

Restoration of Glucose Counterregulation by Islet Transplantation in Long-standing Type 1 Diabetes

Patients with long-standing type 1 diabetes (T1D) may exhibit defective glucose counterregulation and impaired hypoglycemia symptom recognition that substantially increase their risk for experiencing severe hypoglycemia. The purpose of this study was to determine whether intrahepatic islet transplantation improves endogenous glucose production (EGP) in response to hypoglycemia in T1D patients experiencing severe hypoglycemia. We studied longitudinally subjects (n = 12) with ∼30 years, disease duration before and 6 months after intrahepatic islet transplantation using stepped hyperinsulinemic-hypoglycemic and paired hyperinsulinemic-euglycemic clamps with infusion of 6,6-²H₂-glucose and compared the results with those from a nondiabetic control group (n = 8). After islet transplantation, HbA_1c was normalized, and time spent while hypoglycemic (<70 mg/dL) was nearly abolished as indicated by continuous glucose monitoring. In response to insulin-induced hypoglycemia, C-peptide (absent before transplant) was appropriately suppressed, glucagon secretion was recovered, and epinephrine secretion was improved after transplantation. Corresponding to these hormonal changes, the EGP response to insulin-induced hypoglycemia, which was previously absent, was normalized after transplantation, with a similar effect seen for autonomic symptoms. Because the ability to increase EGP is ultimately required to circumvent the development of hypoglycemia, these results provide evidence that intrahepatic islet transplantation can restore glucose counterregulation in long-standing T1D and support its consideration as treatment for patients with hypoglycemia unawareness experiencing severe hypoglycemia.     

Genetic Study of an Indian Family with Cherubism

Cherubism (OMIM : 118400) is an autosomal dominant disorder affecting mainly facial bones leading to disfigurement of face needing medical and surgical attention besides impairing the self esteem of person. At present, there is no medical cure and there is limited indication for surgery in such cases. So, correct diagnosis is of paramount importance to both treating physician and family. Here, the authors report a family with two affected members (mother and daughter) who were tested positive for a known pathogenic mutation and thus offered timely treatment and adequate genetic counseling.     

Sustained effects of transdermal nitroglycerin in patients with angina pectoris

The antianginal efficacy of a transdermal therapeutic delivery system for nitroglycerin (TNG) was compared with that of placebo in a double-blind crossover study. Twenty-five patients with stable angina pectoris were evaluated. The transdermal system delivered 5 mg of nitroglycerin over a 24-hour period and was applied once every 48 hours. Treadmill exercise testing (Bruce protocol) was done 48 hours after the patch was applied in the first phase of the crossover and at the conclusion of the second phase of the crossover, 48 hours after the final dose of the second treatment. Exercise performance was significantly improved (P less than 0.05, analysis of covariance) with TNG as compared with placebo, as were frequency of episodes of angina and nitroglycerin consumption (P less than 0.05, analysis of variance). The incidence of mild-to-moderate headache in patients was greater during treatment with TNG (20%) than during placebo treatment (6.7%). Four cases of mild transient dermatitis and occasional reports of dizziness, lightheadedness, and nausea were noted.     

A Risk Score to Predict Arrhythmias in Patients with Unexplained Syncope

OBJECTIVES: To develop and validate a risk score predicting arrhythmias for patients with syncope remaining unexplained after emergency department (ED) noninvasive evaluation. METHODS: One cohort of 175 patients with unexplained syncope (Geneva, Switzerland) was used to develop and cross-validate the risk score; a second cohort of 269 similar patients (Pittsburgh, PA) was used to validate the system. Arrhythmias as a cause of syncope were diagnosed by cardiac monitoring or electrophysiologic testing. Data from the patient's history and 12-lead emergency electrocardiography (ECG) were used to identify predictors of arrhythmias. Logistic regression was used to identify predictors for the risk-score system. Risk-score performance was measured by comparing the proportions of patients with arrhythmias at various levels of the score and receiver operating characteristic (ROC) curves. RESULTS: The prevalence of arrhythmic syncope was 17% in the derivation cohort and 18% in the validation cohort. Predictors of arrhythmias were abnormal ECG (odds ratio [OR]: 8.1, 95% confidence interval [CI]=3.0 to 22.7), a history of congestive heart failure (OR: 5.3, 95% CI=1.9 to 15.0), and age older than 65 (OR: 5.4, 95% CI=1.1 to 26.0). In the derivation cohort, the risk of arrhythmias ranged from 0% (95% CI=0 to 6) in patients with no risk factors to 6% (95% CI=1 to 15) for patients with one risk factor, 41% (95% CI=26 to 57) for patients with two risk factors, and 60% (95% CI = 32 to 84) for those with three risk factors. In the validation cohort, these proportions varied from 2% (95% CI=0 to 7) with no risk factors to 17% (95% CI=10 to 27) with one risk factor, 35% (95% CI=24 to 46) with two risk factors, and 27% (95% CI=6 to 61) with three risk factors. Areas under the ROC curves ranged from 0.88 (95% CI=0.84 to 0.91) for the derivation cohort to 0.84 (95% CI=0.77 to 0.91) after cross-validation within the same cohort and 0.75 (95% CI=0.68 to 0.81) for the external validation cohort. CONCLUSIONS: In patients with unexplained syncope, a risk score based on clinical and ECG factors available in the ED identifies patients at risk for arrhythmias.     

Eplerenone in the Treatment of Polypoidal Choroidal Vasculopathy

Overactivation of mineralocorticoid receptor pathways has been implicated in the pathophysiology of central serous chorioretinopathy (CSCR). Recently, mineralocorticoid receptor antagonists such as eplerenone have demonstrated success in treating subretinal fluid in CSCR. This case demonstrates a patient who was initially presumed to have subretinal fluid secondary to CSCR and was started on a trial of oral eplerenone. It quickly became evident that her subretinal fluid was secondary to a peripapillary polypoidal choroidal vasculopathy network, but she demonstrated a significant improvement with oral eplerenone. To the authors'' knowledge, this is the first case of eplerenone use to treat polypoidal choroidal vasculopathy.Key Words: Eplerenone, Mineralocorticoid antagonist, Polypoidal choroidal vasculopathy