Diagnosis and Treatment > Signs and Symptoms
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Summary
Hereditary hypophosphatemic rickets with hypercalciuria (HHRH) is a rare, autosomal recessive disorder caused by mutations in the SLC34A3 gene that encodes the renal sodium-dependent phosphate cotransporter 2c (NaPi-IIc). It may present as intermittent mild hypercalcemia which may attract initial diagnostic attention but appreciation of concomitant hypophosphatemia is critical for consideration of the necessary diagnostic approach. A 21-year-old woman was assessed by adult endocrinology for low bone mass. She initially presented age two with short stature, nephrocalcinosis and mild intermittent hypercalcemia with hypercalciuria. She had no evidence of medullary sponge kidney or Fanconi syndrome and no bone deformities, pain or fractures. She had recurrent episodes of nephrolithiasis. In childhood, she was treated with hydrochlorothiazide to reduce urinary calcium. Upon review of prior investigations, she had persistent hypophosphatemia with phosphaturia, low PTH and a high-normal calcitriol. A diagnosis of HHRH was suspected and genetic testing confirmed a homozygous c.1483G>A (p.G495R) missense mutation of the SLC34A3 gene. She was started on oral phosphate replacement which normalized her serum phosphate, serum calcium and urine calcium levels over the subsequent 5 years. HHRH is an autosomal recessive condition that causes decreased renal reabsorption of phosphate, leading to hyperphosphaturia, hypophosphatemia and PTH-independent hypercalcemia due to the physiologic increase in calcitriol which also promotes hypercalciuria. Classically, patients present in childhood with bone pain, vitamin D-independent rickets and growth delay. This case of a SLC34A3 mutation illustrates the importance of investigating chronic hypophosphatemia even in the presence of other more common electrolyte abnormalities.
Learning points:
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Hypophosphatemia is an important diagnostic clue that should not be ignored, even in the face of more common electrolyte disorders.
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HHRH is a cause of PTH-independent hypophosphatemia that may also show hypercalcemia.
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HHRH is a cause of hypophosphatemic nephrocalcinosis that should not be treated with calcitriol, unlike other congenital phosphate wasting syndromes.
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Some congenital phosphate wasting disorders may not present until adolescence or early adulthood.
Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
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Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
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Department of General Surgery, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
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Summary
Spontaneous remission of primary hyperparathyroidism (PHPT) due to necrosis and haemorrhage of parathyroid adenoma, the so-called ‘parathyroid auto-infarction’ is a very rare, but previously described phenomenon. Patients usually undergo parathyroidectomy or remain under close clinical and biochemical surveillance. We report two cases of parathyroid auto-infarction diagnosed in the same tertiary centre; one managed surgically and the other conservatively up to the present time. Case #1 was a 51-year old man with PHPT (adjusted (adj.) calcium: 3.11 mmol/L (reference range (RR): 2.20–2.60 mmol/L), parathyroid hormone (PTH) 26.9 pmol/L (RR: 1.6–6.9 pmol/L) and urine calcium excretion consistent with PHPT) referred for parathyroidectomy. Repeat biochemistry 4 weeks later at the surgical clinic showed normal adj. calcium (2.43 mmol/L) and reduced PTH. Serial ultrasound imaging demonstrated reduction in size of the parathyroid lesion from 33 to 17 mm. Twenty months later, following recurrence of hypercalcaemia, he underwent neck exploration and resection of an enlarged right inferior parathyroid gland. Histology revealed increased fibrosis and haemosiderin deposits in the parathyroid lesion in keeping with auto-infarction. Case #2 was a 54-year-old lady admitted with severe hypercalcaemia (adj. calcium: 4.58 mmol/L, PTH 51.6 pmol/L (RR: 1.6–6.9 pmol/L)) and severe vitamin D deficiency. She was treated with intravenous fluids and pamidronate and 8 days later developed symptomatic hypocalcaemia (1.88 mmol/L) with dramatic decrease of PTH (17.6 pmol/L). MRI of the neck showed a 44 mm large cystic parathyroid lesion. To date, (18 months later), she has remained normocalcaemic.
Learning points:
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Primary hyperparathyroidism (PHPT) is characterised by excess parathyroid hormone (PTH) secretion arising mostly from one or more autonomously functioning parathyroid adenomas (up to 85%), diffuse parathyroid hyperplasia (<15%) and in 1–2% of cases from parathyroid carcinoma.
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PHPT and hypercalcaemia of malignancy, account for the majority of clinical presentations of hypercalcaemia.
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Spontaneous remission of PHPT due to necrosis, haemorrhage and infarction of parathyroid adenoma, the so-called ‘parathyroid auto-infarction’, ‘auto-parathyroidectomy’ or ‘parathyroid apoplexy’ is a very rare in clinical practice but has been previously reported in the literature.
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In most cases, patients with parathyroid auto-infarction undergo parathyroidectomy. Those who are managed conservatively need to remain under close clinical and biochemical surveillance long-term as in most cases PHPT recurs, sometimes several years after auto-infarction.
Autonomous University of Barcelona, Barcelona, Spain
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Autonomous University of Barcelona, Barcelona, Spain
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Autonomous University of Barcelona, Barcelona, Spain
Centre for Biomedical Research Network on Rare Diseases (CIBERER), Madrid, Spain
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Endocrinology and Diabetes Research Group, BioCruces Health Research Institute, UPV-EHU, CIBERDEM, Cruces University Hospital, Barakaldo, Spain
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Centre for Biomedical Research Network on Rare Diseases (CIBERER), Madrid, Spain
Department of Pediatrics, Children’s University Hospital Vall Hebron, Barcelona, Spain
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Autonomous University of Barcelona, Barcelona, Spain
Centre for Biomedical Research Network on Rare Diseases (CIBERER), Madrid, Spain
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Autonomous University of Barcelona, Barcelona, Spain
Centre for Biomedical Research Network on Rare Diseases (CIBERER), Madrid, Spain
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Summary
Two pediatric patients with different causes of hyperparathyroidism are reported. First patient is a 13-year-old male with severe hypercalcemia due to left upper parathyroid gland adenoma. After successful surgery, calcium and phosphate levels normalized, but parathormone levels remained elevated. Further studies revealed a second adenoma in the right gland. The second patient is a 13-year-old female with uncommon hypercalcemia symptoms. Presence of pathogenic calcium-sensing receptor gene (CASR) mutation was found, resulting in diagnosis of symptomatic familial hypocalciuric hypercalcemia. Cinacalcet, a calcium-sensing agent that increases the sensitivity of the CASR, was used in both patients with successful results.
Learning points:
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Hyperparathyroidism is a rare condition in pediatric patients. If not treated, it can cause serious morbidity.
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Genetic tests searching for CASR or MEN1 gene mutations in pediatric patients with primary hyperparathyroidism should be performed.
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Cinacalcet has been effective for treating different causes of hyperparathyroidism in our two pediatric patients.
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Treatment has been well tolerated and no side effects have been detected.
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Summary
Parathyroid carcinoma is an extremely rare endocrine malignancy that accounts for less than 1% of cases of primary hyperparathyroidism. We report a 44-year-old woman who presented with fatigue and diffuse bone pain. Laboratory findings revealed highly elevated serum calcium and parathyroid hormone (PTH) levels and a 4.5 × 3 × 2.5 cm cystic lesion in the lower pole of the right thyroid lobe that was shown histologically to be a parathyroid carcinoma. Ten years later, the patient developed brain and pulmonary metastases and recurrence of PTH-related hypercalcemia. Treatment of hypercalcemia along with localized radiotherapy and various chemotherapy regimens failed to induce a biochemical or radiological response. In conclusion, parathyroid carcinoma is a rare neoplasia that may develop metastases even after prolonged follow-up, for which there is no evidence-based treatment besides surgery. Different chemotherapeutic schemes did not prove to be of any benefit in our case highlighting the need for registering such patients to better understand tumor biology and develop specific treatment.
Learning points:
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Metastases can develop many years after parathyroid cancer diagnosis.
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Surgery is the only curative treatment for parathyroid carcinoma.
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Chemotherapy and radiotherapy prove to be ineffective in parathyroid cancer treatment.
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Patient registering is required in order to delineate underlining pathology and offer specific treatment.
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Summary
MEN1-associated pancreatic neuroendocrine tumors (pNETs) may potentially express distinct hormones, but the mechanism has not been elucidated. Transcription factors such as MafA and Pdx1 have been identified to lead to beta cell differentiation, while Arx and Brn4 to alpha cell differentiation in developing pancreas. We hypothesized those transcription factors are important to produce specific hormones in pNETs, similarly to developing pancreas, and examined the expression of transcription factors in a case of MEN1 who showed immunohistological coexistence of several hormone-producing pNETs including insulinoma. A 70-year-old woman was found to manifest hypoglycemia with non-suppressed insulinemia and hypercalcemia with elevated PTH level. She was diagnosed as MEN1 based on the manifestation of primary hyperparathyroidism, pituitary adenoma and insulinoma, with genetic variation of MEN1 gene. She had pylorus-preserving pancreaticoduodenectomy because CT scan and SACI test indicated that insulinoma was localized in the head of the pancreas. Histopathological finding was MEN1-associated NET, G1. Interestingly, immunohistological examination of the resected pancreas revealed that two insulinomas, a glucagon-positive NET and a multiple hormone-positive NET coexisted. Hence, we examined the expression of transcription factors immunohistochemically to elucidate the role of the transcription factors in MEN1-associated hormone-producing pNETs. We observed homogeneous expressions of MafA and Pdx1 in insulinomas and Arx in glucagon-positive NET, respectively. Moreover, multiple hormone-positive NETs expressed several transcription factors heterogeneously. Collectively, our results suggested that transcription factors could play important roles in the production of specific hormones in MEN1-associated pNETs, similar to islet differentiation.
Learning points:
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To date, it has been shown that different hormone-producing tumors coexist in MEN1-associated pNETs; however, the underlying mechanism of the hormone production in MEN1-associated pNETs has not been well elucidated.
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Although this case presented symptomatic hypoglycemia, several hormone-producing pNETs other than insulinoma also coexisted in the pancreas.
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Immunohistochemical analysis showed MafA and Pdx1 expressions distinctly in insulinoma, and Arx expression particularly in a glucagon-positive NET, while a multiple hormone-positive NET expressed MafA, Pdx1 and Arx.
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Collectively, clinicians should consider that several hormone-producing pNETs may coexist in a MEN1 case and examine both endocrinological and histopathological analysis of pNETs, regardless of whether symptoms related to the excess of hormones are observed or not.
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Summary
Multiple endocrine neoplasia type 1 (MEN-1) is a rare autosomal-dominant disease characterized by tumors in endocrine and/or non endocrine organs due to mutations in MEN1 encoding a nuclear scaffold protein‘menin’ involved in regulation of different cellular activities. We report a novel 14 bp MEN1 deletion mutation in a 35-year-old female with history of recurrent epigastric pain, vomiting, loose stools and weight loss. On evaluation she was diagnosed to have multifocal gastro-duodenal gastrinoma with paraduodenal lymph nodes and solitary liver metastasis. She was also found to have primary hyperparathyroidism with bilateral inferior parathyroid adenoma. Pancreatico-duodenectomy with truncalvagotomy was performed. Four months later, radiofrequency ablation (RFA) of segment 4 of the liver was done followed by three and a half parathyroidectomy. MEN1 screening was carried out for the patient and her family members. MEN-1 sequencing in the patient revealed a heterozygous 14 bp exon 8 deletion. Evaluation for pathogenicity and protein structure prediction showed that the mutation led to a frameshift thereby causing premature termination resulting in a truncated protein. To conclude, a novel pathogenic MEN1 deletion mutation affecting its function was identified in a patient with hyperparathyroidism and gastrinoma. The report highlights the clinical consequences of the novel mutation and its impact on the structure and function of the protein. It also provides evidence for co-existence of pancreatic and duodenal gastrinomas in MEN1 syndrome. MEN1 testing provides important clues regarding etiology and therefore should be essentially undertaken in asymptomatic first degree relatives who could be potential carriers of the disease.
Learning points
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Identification of a novel pathogenic MEN1 deletion mutation.
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MEN1 mutation screening in patients with pituitary, parathyroid and pancreatic tumors, and their first degree relatives gives important clues about the etiology.
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Pancreatic and duodenal gastrinomas may co-exist simultaneously in MEN1 syndrome.
