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Open access

Mads Ryø Jochumsen, Peter Iversen and Anne Kirstine Arveschoug

Summary

A case of follicular thyroid cancer with intense focal Methionine uptake on 11C-Methionine PET/CT is reported here. The use of 11C-Methionine PET in differentiated thyroid cancer is currently being investigated as a surrogate tracer compared to the more widely used 18F-FDG PET. This case illustrates the potential incremental value of this modality, not only in the localizing of parathyroid adenoma, but also indicating that 11C-Methionine PET might have a potential of increasing the pretest likelihood of thyroid malignancy in a cold nodule with highly increased Sestamibi uptake.

Learning points:

  • 11C-Methionine PET/CT and 18F-Fluorocholine PET/CT often visualizes the parathyroid adenoma in case of negative Tc-99m-MIBI SPECT/CT.

  • A cold nodule in Tc-99m Pertechnetat thyroid scintigraphy with a negative Sestamibi scintigraphy has a very low probability of being malignant.

  • However, the pretest likelihood of thyroid cancer in a cold nodule with increased Sestamibi uptake is low.

  • 11C-Methionine PET might have a potential incremental value in increasing the pretest likelihood of thyroid malignancy in a cold nodule with highly increased Sestamibi uptake.

Open access

Marianne Geilswijk, Lise Lotte Andersen, Morten Frost, Klaus Brusgaard, Henning Beck-Nielsen, Anja Lisbeth Frederiksen and Dorte Møller Jensen

Summary

Hypoglycemia during pregnancy can have serious health implications for both mother and fetus. Although not generally recommended in pregnancy, synthetic somatostatin analogues are used for the management of blood glucose levels in expectant hyperinsulinemic mothers. Recent reports suggest that octreotide treatment in pregnancy, as well as hypoglycemia in itself, may pose a risk of fetal growth restriction. During pregnancy, management of blood glucose levels in familial hyperinsulinemic hypoglycemia thus forms a medical dilemma. We report on pregnancy outcomes in a woman with symptomatic familial hyperinsulinemic hypoglycemia, type 3. During the patient’s first pregnancy with a viable fetus octreotide treatment was instituted in gestational age 23 weeks to prevent severe hypoglycemic incidences. Fetal growth velocity declined, and at 37 weeks of gestation, intrauterine growth retardation was evident. During the second pregnancy with a viable fetus, blood glucose levels were managed through dietary intervention alone. Thus, the patient was advised to take small but frequent meals high in fiber and low in carbohydrates. Throughout pregnancy, no incidences of severe hypoglycemia occurred and fetal growth velocity was normal. We conclude that octreotide treatment during pregnancy may pose a risk of fetal growth restriction and warrants careful consideration. In some cases of familial hyperinsulinemic hypoglycemia, blood glucose levels can be successfully managed through diet only, also during pregnancy.

Learning points:

  • Gain-of-function mutations in GCK cause familial hyperinsulinemic hypoglycemia.

  • Hypoglycemia during pregnancy may have serious health implications for mother and fetus.

  • Pregnancy with hyperinsulinism represents a medical dilemma as hypoglycemia as well as octreotide treatment may pose a risk of fetal growth restriction.

  • In some cases of familial hyperinsulinemic hypoglycemia, blood glucose levels can be successfully managed through diet only.

Open access

Etienne Larger, Nicolai J Wewer Albrechtsen, Lars H Hansen, Richard W Gelling, Jacqueline Capeau, Carolyn F Deacon, Ole D Madsen, Fumiatsu Yakushiji, Pierre De Meyts, Jens J Holst and Erica Nishimura

Summary

Glucagon stimulates hepatic glucose production by activating specific glucagon receptors in the liver, which in turn increase hepatic glycogenolysis as well as gluconeogenesis and ureagenesis from amino acids. Conversely, glucagon secretion is regulated by concentrations of glucose and amino acids. Disruption of glucagon signaling in rodents results in grossly elevated circulating glucagon levels but no hypoglycemia. Here, we describe a patient carrying a homozygous G to A substitution in the invariant AG dinucleotide found in a 3′ mRNA splice junction of the glucagon receptor gene. Loss of the splice site acceptor consensus sequence results in the deletion of 70 nucleotides encoded by exon 9, which introduces a frame shift and an early termination signal in the receptor mRNA sequence. The mutated receptor neither bound 125I-labeled glucagon nor induced cAMP production upon stimulation with up to 1 µM glucagon. Despite the mutation, the only obvious pathophysiological trait was hyperglucagonemia, hyperaminoacidemia and massive hyperplasia of the pancreatic α-cells assessed by histology. Our case supports the notion of a hepato–pancreatic feedback system, which upon disruption leads to hyperglucagonemia and α-cell hyperplasia, as well as elevated plasma amino acid levels. Together with the glucagon-induced hypoaminoacidemia in glucagonoma patients, our case supports recent suggestions that amino acids may provide the feedback link between the liver and the pancreatic α-cells.

Learning points:

  • Loss of function of the glucagon receptor may not necessarily lead to the dysregulation of glucose homeostasis.

  • Loss of function of the glucagon receptor causes hyperaminoacidemia, hyperglucagonemia and α-cell hyperplasia and sometimes other pancreatic abnormalities.

  • A hepato–pancreatic feedback regulation of the α-cells, possibly involving amino acids, may exist in humans.

Open access

Anne Soejbjerg, Suzan Dyve, Steen Baerentzen, Georg Thorsell, Per L Poulsen, Jens O L Jorgensen and Ulla Kampmann

Summary

Solitary sellar plasmacytomas are exceedingly rare and difficult to distinguish from other pituitary tumors. We report a case of a 62-year-old woman presenting with blurred vision of the right eye and tenderness of the right temporal region, which was interpreted as temporal arteritis. MRI revealed a pituitary mass lesion (20mm×14mm×17mm) without compression of the optic chiasm and her pituitary function was normal. Pituitary surgery was undertaken due to growth of the lesion, and histopathological examination showed a highly cellular neoplasm composed of mature monoclonal plasma cells. Subsequent examinations revealed no evidence of extrasellar myeloma. The patient received pituitary irradiation and has remained well and free of symptoms apart from iatrogenic central diabetes insipidus. Until now, only eight cases of solitary sellar plasmacytoma have been reported. Most frequent symptoms stem from compression of the cranial nerves in the cavernous sinus (III, IV, V), whereas the anterior pituitary function is mostly intact.

Learning points

  • A solitary plasmacytoma is a rare cause of a sellar mass lesion.

  • The radiological and clinical features are nonspecific, but cranial nerve affection and intact pituitary function are usually present.

  • The diagnosis is made histologically and has important therapeutic implications.

Open access

Pia T Dinesen, Jakob Dal, Plamena Gabrovska, Mette Gaustadnes, Claus H Gravholt, Karen Stals, Judit Denes, Sylvia L Asa, Márta Korbonits and Jens O L Jørgensen

Summary

A patient of Cushing's disease (CD) characterized by a large tumor and only subtle symptoms of hormonal hypersecretion was examined. The patient had a germline variant in the aryl hydrocarbon receptor-interacting protein (AIP) gene. A 50-year-old male presenting with headache was diagnosed with a large pituitary tumor by magnetic resonance imaging (MRI). His visual fields were intact and he exhibited no features of CD. Owing to an exuberant response to synacthen, an overnight dexamethasone suppression test was performed revealing inadequate suppression of plasma cortisol (419 nmol/l). Owing to tumor growth and visual field impairment, he underwent transsphenoidal surgery and developed hypocortisolemia. The pathology specimen revealed a sparsely granulated corticotrope adenoma. Postoperative MRI showed a large tumor remnant. The patient developed skin hyperpigmentation and a synacthen test demonstrated high basal and stimulated cortisol levels; an overnight dexamethasone suppression test showed no suppression (791 nmol/l) and elevated plasma ACTH levels (135 ng/l). A transcranial operation was performed followed by radiotherapy. Two months after radiotherapy, he developed secondary adrenocortical failure. Genetic testing revealed an AIP variant of unknown significance (p.R16H) without loss of the normal AIP allele in the tumor. A literature review showed ten CD patients with AIP gene variants, of whom five (including our case) were p.R16H. CD is occasionally dominated by pituitary tumor growth rather than symptoms of hypersecretion. The particular AIP gene variant identified in our patient is shared by four other reported cases of CD. Future studies are needed to assess whether the reported AIP gene variant is more than just coincidental.

Learning points

  • CD is occasionally dominated by pituitary tumor growth rather than symptoms of hypersecretion.

  • Resolution of both tumor remnant and hormonal hypersecretion may occur within 2 months after postoperative radiotherapy.

  • The particular AIP gene variant identified in our patient is shared by four other reported cases of CD.