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Summary
Juxtaglomerular cell tumour (JGCT) is an unusually encountered clinical entity. A 33-year-old man with severe long-standing hypertension and hypokalaemia is described. The patient also suffered from polyuria, polydipsia, nocturia and severe headaches. On admission, laboratory investigation revealed hypokalaemia, kaliuresis, high aldosterone and renin levels, and the abdomen CT identified a mass of 4 cm at the right kidney. Kidney function was normal. Following nephrectomy, the histological investigation revealed the presence of a JGCT. Immunostaining was positive for CD34 as well as for smooth muscle actin and vimentin. Following surgery, a marked control of his hypertension with calcium channel blockers and normalization of the serum potassium, renin or aldosterone levels were reached. According to our findings, JGCT could be included in the differential diagnosis of secondary hypertension as it consists of a curable cause. The association of JGCT with hypertension and hypokalaemia focusing on the clinical presentation, diagnostic evaluation and management is herein discussed and a brief review of the existing literature is provided.
Learning points
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Juxtaglomerular cell tumours (JGCT), despite their rarity, should be included in the differential diagnosis of secondary hypertension as they consist of a curable cause of hypertension.
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JGCT could be presented with resistant hypertension along with hypokalaemia, kaliuresis and metabolic alkalosis. Early recognition and management can help to prevent cardiovascular complications.
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Imaging (enhanced CT scans) may be considered as the primary diagnostic tool for the detection of renal or JGCT.
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For the confirmation of the diagnosis, a histopathologic examination is needed.
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Summary
A 33-year-old gentleman of Egyptian heritage presented with a 21 years history of unexplained and recurrent hypercalcaemia, nephrolithiasis, nephrocalcinosis, and myocarditis. A similar history was also found in two first-degree relatives. Further investigation into the vitamin D metabolism pathway identified the biochemical hallmarks of infantile hypercalcaemia type 1 (IIH). A homozygous, likely pathogenic, variant in CYP24A1 was found on molecular genetic analysis confirming the diagnosis. Management now focuses on removing excess vitamin D from the metabolic pathway as well as reducing calcium intake to achieve serum-adjusted calcium to the middle of the reference range. If undiagnosed, IIH can cause serious renal complications and metabolic bone disease.
Learning points
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Infantile hypercalcaemia type 1 (IIH) is an autosomal recessive disorder characterised by homozygous mutations in the CYP24A1 gene that encodes the 24-hydroxylase enzyme used to convert active vitamin D metabolites such as 1,25-(OH)2-vitamin D into their inactive form.
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IIH should be questioned in individuals presenting with a history of unexplained hypercalcaemia, especially if presenting from childhood and/or where there is an accompanying family history of the same in first and/or second degree relatives, causing complications such as nephrocalcinosis, pericarditis, and calcium-based nephrolithiasis.
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Associated biochemistry of IIH is persistent mild to moderate hypercalcaemia, normal or raised 25-(OH)-vitamin D and elevated 1,25-(OH)2-vitamin D. An elevated ratio of 25-(OH)-vitamin D to 24,25-(OH)2-vitamin D can be a useful marker of defects in the 24-hydroxylase enzyme, whose measurement can be facilitated through the supra-regional assay service.
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Management should focus on limiting the amount of vitamin D introduced into the body either via sunlight exposure or supplementation in addition to calcium dietary restriction to try and maintain appropriate calcium homeostasis
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Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
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Search for other papers by Fady Hannah-Shmouni in
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Summary
Succinate dehydrogenase deficiency has been associated with several neoplasias, including renal cell carcinoma (RCC) and those associated with hereditary paraganglioma (PGL)/ pheochromocytoma (PHEO) syndromes, Carney dyad, and Carney triad. Carney triad is a rare multitumoral syndrome characterized by co-existing PGL, gastrointestinal stromal tumor (GIST), and pulmonary chondroma (CHO). We report a case of a 57-year-old male who presented with para-aortic and gastroesophogeal masses, and a right renal superior pole lesion, which were classified as multiple PGLs, a GIST, and a clear cell renal carcinoma, respectively, on pathology following surgical resection. Additionally, a CHO was diagnosed radiologically, although no biopsy was performed. A diagnosis of Carney triad was made. SDHB immunohistochemical staining was negative for the PGL and the GIST, indicating SDH-deficiency. Interestingly, the renal cell carcinoma (RCC) stained positive for both SDHB and SDHA. Subsequent genetic screening of SDH subunit genes revealed a germline inactivating heterozygous SDHA pathogenic variant (c.91 C>T, p.R31X). Loss of heterozygosity was not detected at the tumor level for the RCC, which likely indicated the SDHA variant would not be causative of the RCC, but could still predispose to the development of neoplasias. To the knowledge of the authors this is the first reported case of an SDHA pathogenic variant in a patient with Carney triad complicated by RCC.
Learning points
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The succinate dehydrogenase enzyme is encoded by four subunit genes (SDHA, SDHB, SDHC, and SDHD; collectively referred to as SDHx), which have been implicated in several neoplasias and are classified as tumor suppressor genes.
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Carney triad is a rare multiple-neoplasia syndrome presenting as an association of PGLs, GISTs, and CHOs.
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Carney triad is most commonly associated with hypermethylation of SDHC as demonstrated in tumor tissue, but approximately 10% of cases are due to pathogenic SDHx variants.
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Although SDHB pathogenic variants are most commonly reported in SDH-deficient renal cell carcinoma, SDHA disease-causing variants have been reported in rare cases.
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Search for other papers by Swati Mehrotra in
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Summary
We report a rare case of concurrent medullary thyroid cancer (MTC) and papillary thyroid cancer (PTC) with intermixed disease in several of the lymph node (LN) metastases in a patient who was subsequently diagnosed with clear cell renal cell carcinoma (RCC). A 56 year old female presented with dysphagia and was found to have a left thyroid nodule and left superior cervical LN with suspicious sonographic features. Fine needle aspiration biopsy (FNAB) demonstrated PTC in the left thyroid nodule and MTC in the left cervical LN. Histopathology demonstrated multifocal PTC with 3/21 LNs positive for metastatic PTC. One LN in the left lateral neck dissection exhibited features of both MTC and PTC within the same node. In the right lobe, a 0.3 cm focus of MTC with extra-thyroidal extension was noted. Given persistent calcitonin elevation, a follow-up ultrasound displayed an abnormal left level 4 LN. FNAB showed features of both PTC and MTC on the cytopathology itself. The patient underwent repeat central and left radical neck dissection with 3/6 LNs positive for PTC in the central neck and 2/6 LNs positive for intermixed PTC and MTC in the left neck. There was no evidence of distant metastases on computed tomography and whole body scintigraphy, however a 1.9 x 2.5 cm enhancing mass within the right inter-polar kidney was discovered. This lesion was highly suspicious for RCC. Surgical pathology revealed a 2.5 cm clear cell RCC, Fuhrman grade 2/4, with negative surgical margins. She continues to be observed with stable imaging of her triple malignancies.
Learning points:
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Mixed medullary-papillary thyroid neoplasm is characterized by the presence of morphological and immunohistochemical features of both medullary and papillary thyroid cancers within the same lesion. Simultaneous occurrence of these carcinomas has been previously reported, but a mixed disease within the same lymph node is an infrequent phenomenon.
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Prognosis of mixed medullary-papillary thyroid carcinomas is determined by the medullary component. Therefore, when PTC and MTC occur concurrently, the priority should be given to the management of MTC, which involves total thyroidectomy and central lymph node dissection.
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Patients with thyroid cancer, predominantly PTC, have shown higher than expected rates of RCC. To our knowledge, this is the first report describing the combination of MTC, PTC, and RCC in a single patient.
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Department of Internal Medicine and Endocrinology (DoH), Aarhus University Hospital, Aarhus N, Denmark
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Summary
Excessive intake of licorice may cause pseudohyperaldosteronism which, in turn, may lead to hypertension and hypokalemia. Severe hypokalemia may lead to electrocardiogram (ECG) changes including long QT interval potentially progressing into malignant arrhythmias. Here we present a 43-year-old woman admitted to the hospital with chest pain and a stinging sensation in the upper extremities. Her peak blood pressure was 177/98 mmHg and the blood test revealed low plasma potassium of 1.9 mmol/L. The ECG revealed flattened T-waves and long QT interval. Prior to admission, the patient had increased licorice ingestion to a total of some 70 g daily. The licorice intake was stopped and potassium was administrated orally and intravenously. Plasma potassium normalized and the ECG changes remitted. To our knowledge a few other cases of licorice-induced pseudohyperaldosteronism and long QT interval have previously been reported. This underlines the importance of quantifying licorice intake in younger people with unexplained high blood pressure and low potassium.
Learning points:
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Even small amounts of licorice daily may increase the risk of developing hypertension; therefore, licorice should be asked for specifically.
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Even though licorice intake is very easy to cover in the patient’s history, it is often missed.
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Excessive licorice intake may course severe hypokalemia causing long QT interval in the ECG recording, potentially progressing into arrhythmias and even cardiac arrest/sudden death.
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Hypokalemia <3 mmol/L and present ECG changes should be treated with potassium intravenously.
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Licorice-induced hypertension may be associated with syndrome of apparent mineralocorticoid excess (SAME). Plasma renin and aldosterone are both low at diagnosis and normalize when licorice is stopped.
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Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan
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Department of Pathology, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
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Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan
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Summary
We report the renal histology of a 66-year-old man with hypertension, cardiovascular disease, and a 30-year history of type 2 diabetes mellitus with proliferative diabetic retinopathy, diabetic neuropathy, and diabetic foot status post toe amputation. Urinary protein excretion was 1.4 g/gCr, serum creatinine level 0.86 mg/dL, estimated glomerular filtration rate 69 mL/min/1.73 m2, and HbA1c 13–15%, despite using insulin. Light microscopy showed global glomerulosclerosis in 37% of the glomeruli, but the remaining glomeruli were intact. Significant polar vasculosis was present, while arteriolar sclerosis was mild. Electron microscopy revealed a thickened glomerular basement membrane, which is compatible with the early stage of diabetic glomerulopathy. The presented case was unique because glomerular changes seen typically in diabetes were not seen in the patient, despite the long-standing history of diabetes and diabetic comorbidities, while prominent polar vasculosis was found. Polar vascular formation helps preserve the glomeruli by allowing hyperosmotic blood bypass the glomeruli; this decreases intraglomerular pressure and minimizes glomerular endothelial damage.
Learning points:
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A 66-year-old man with a 30-year history of type 2 diabetes mellitus with poor glycemic control underwent renal biopsy, which showed scarce glomerular changes typically seen in diabetic kidney disease and instead revealed significant polar vasculosis.
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Past studies demonstrated that the increased small vessels around the vascular hilus in diabetic patients originated from the afferent arterioles and drained into the peritubular capillaries.
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Polar vascular formation may preserve glomerular function by allowing the blood flow to bypass the glomeruli and decreasing the intraglomerular pressure, which minimizes endothelial damage of the glomerular tufts.
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Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre and Cancer Research UK Cambridge Centre, Cambridge, UK
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Summary
Activating mutations in AVPR2 are associated with nephrogenic syndrome of inappropriate antidiuresis (NSIAD). NSIAD causes hyponatremia, decreased serum osmolality and clinical symptoms, which may present from birth or in infancy and include hypotonia, irritability, vomiting and/or seizures. Symptoms in later life are often less specific and include malaise, dizziness, confusion, tiredness and headache. NSIAD is a rare X-linked condition, which is associated with a variable phenotype in males, of whom some present in infancy but others do not become symptomatic until adulthood, or occasionally, never. Female carriers may present with episodes of hyponatremia, usually found incidentally. Literature in this field is limited; namely, two clinical reports describing a female proband, both diagnosed in infancy. We describe, for the first time, the case of an adult female proband with NSIAD, who had longstanding associated symptoms of tiredness, headache, temporary memory loss and mood changes as well as hyponatremia and decreased serum osmolality. A water load test demonstrated an inability to dilute urine and gene sequencing confirmed a recurrent activating mutation in AVPR2. The variant was inherited from the proband’s mother who had had longstanding episodes of transient asymptomatic hyponatremia. This is the third report of a female proband with NSIAD and is the first female reported who sought medical treatment for chronic symptoms from adulthood. This case acts as a reminder of the importance of considering NSIAD as a diagnosis in females of all ages with unexplained hyponatremia.
Learning points:
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Activating mutations in the AVPR2 gene are associated with the rare X-linked condition nephrogenic syndrome of inappropriate antidiuresis.
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NSIAD is associated with hyponatremia, decreased serum osmolality and inappropriately increased urinary osmolality. Early clinical symptoms in infancy include hypotonia, irritability, vomiting and/or seizures. Symptoms in later life include malaise, dizziness, confusion, tiredness and headache.
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NSIAD should be considered in female, as well as male, patients who present with unexplained hyponatremia and decreased serum osmolality. Family history may reveal relevant symptoms or biochemical features in other family members. However, family history may not always be informative due to the variable nature of the condition or if the proband has a de novo pathogenic variant.
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A water load test with measurement of AVP may be informative in distinguishing NSIAD from SIADH. Measurement of co-peptin levels may be considered, in substitution for direct measurement of AVP.
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Patients with NSIAD should be counseled about appropriate daily fluid volume intake. Potential episodes of fluid overload should be avoided.
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Summary
A 65-year-old woman was admitted to the emergency unit with a 48 h history of generalised weakness and confusion. On examination, she had mild slurring of speech although there was no other focal neurological deficit. She had profound hyponatraemia (serum sodium level of 100 mmol/L) on admission with the rest of her metabolic parameters being within normal range. Subsequent investigations confirmed the diagnosis of small-cell lung cancer with paraneoplastic syndrome of inappropriate antidiuresis (SIAD). She was monitored closely in high-dependency unit with an attempt to cautiously correct her hyponatraemia to prevent sequelae associated with rapid correction. The patient developed prolonged psychosis (lasting over 2 weeks) and displayed delayed dyskinetic movements, even after a gradual increase in serum sodium levels close to 130 mmol/L. To our knowledge, delayed neurological recovery from profound hyponatraemia (without long-term neurological sequelae) has previously not been reported. This case should alert a clinician regarding the possibility of prolonged although reversible psychosis and dyskinetic movements in a patient presenting with profound symptomatic hyponatraemia.
Learning points:
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Patients with profound hyponatraemia may develop altered sensorium, dyskinesia and psychotic behaviour.
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Full recovery from psychotic symptoms and dyskinesia may be delayed despite cautious correction of serum sodium levels.
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Careful and close monitoring of such patients can help avoid long-term neurological sequelae.
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Summary
Hypokalaemia may present as muscle cramps and Cardiac arrhythmias. This is a condition commonly encountered by endocrinologists and general physicians alike. Herein, we report the case of a 43-year-old gentleman admitted with hypokalaemia, who following subsequent investigations was found to have Gitelman's syndrome (GS). This rare, inherited, autosomal recessive renal tubular disorder is associated with genetic mutations in the thiazide-sensitive sodium chloride co-transporter and magnesium channels in the distal convoluted tubule. Patients with GS typically presents at an older age, and a spectrum of clinical presentations exists, from being asymptomatic to predominant muscular symptoms. Clinical suspicion should be raised in those with hypokalaemic metabolic alkalosis associated with hypomagnesaemia. Treatment of GS consists of long-term potassium and magnesium salt replacement. In general, the long-term prognosis in terms of preserved renal function and life expectancy is excellent. Herein, we discuss the biochemical imbalance in the aetiology of GS, and the case report highlights the need for further investigations in patients with recurrent hypokalaemic episodes.
Learning points
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Recurrent hypokalaemia with no obvious cause warrants investigation for hereditary renal tubulopathies.
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GS is the most common inherited renal tubulopathy with a prevalence of 25 per million people.
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GS typically presents at an older age and clinical suspicion should be raised in those with hypokalaemic metabolic alkalosis associated with hypomagnesaemia.
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Confirmation of diagnosis is by molecular analysis for mutation in the SLC12A3 gene.
