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Open access

Caroline Bachmeier, Chirag Patel, Peter Kanowski and Kunwarjit Sangla

Summary

Primary hyperparathyroidism (PH) is a common endocrine abnormality and may occur as part of a genetic syndrome. Inactivating mutations of the tumour suppressor gene CDC73 have been identified as accounting for a large percentage of hyperparathyroidism-jaw tumour syndrome (HPT-JT) cases and to a lesser degree account for familial isolated hyperparathyroidism (FIHP) cases. Reports of CDC73 whole gene deletions are exceedingly rare. We report the case of a 39 year-old woman with PH secondary to a parathyroid adenoma associated with a large chromosomal deletion (2.5 Mb) encompassing the entire CDC73 gene detected years after parathyroidectomy. This case highlights the necessity to screen young patients with hyperparathyroidism for an underlying genetic aetiology. It also demonstrates that molecular testing for this disorder should contain techniques that can detect large deletions.

Learning points:

  • Necessity of genetic screening for young people with hyperparathyroidism.

  • Importance of screening for large, including whole gene CDC73 deletions.

  • Surveillance for patients with CDC73 gene mutations includes regular calcium and parathyroid hormone levels, dental assessments and imaging for uterine and renal tumours.

Open access

Yasutaka Takeda, Yukihiro Fujita, Kentaro Sakai, Tomoe Abe, Tomonobu Nakamura, Tsuyoshi Yanagimachi, Hidemitsu Sakagami, Jun Honjo, Atsuko Abiko, Yuichi Makino and Masakazu Haneda

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:

  • 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.

  • Although this case presented symptomatic hypoglycemia, several hormone-producing pNETs other than insulinoma also coexisted in the pancreas.

  • 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.

  • 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.

Open access

Run Yu, Danielle Sharaga, Christopher Donner, M Fernando Palma Diaz, Masha J Livhits and Michael W Yeh

Summary

Pheochromocytomatosis, a very rare form of pheochromocytoma recurrence, refers to new, multiple, and often small pheochromocytomas growing in and around the surgical resection bed of a previous adrenalectomy for a solitary pheochromocytoma. We here report a case of pheochromocytomatosis in a 70-year-old female. At age 64 years, she was diagnosed with a 6-cm right pheochromocytoma. She underwent laparoscopic right adrenalectomy, during which the tumor capsule was ruptured. At age 67 years, CT of abdomen did not detect recurrence. At age 69 years, she began experiencing episodes of headache and diaphoresis. At age 70 years, biochemical markers of pheochromocytoma became elevated with normal calcitonin level. CT revealed multiple nodules of various sizes in the right adrenal fossa, some of which were positive on metaiodobenzylguanidine (MIBG) scan. She underwent open resection of pheochromocytomatosis. Histological examination confirmed numerous pheochromocytomas ranging 0.1–1.2 cm in size. Next-generation sequencing of a panel of genes found a novel heterozygous germline c.570delC mutation in TMEM127, one of the genes that, if mutated, confers susceptibility to syndromic pheochromocytoma. Molecular analysis showed that the c.570delC mutation is likely pathogenic. Our case highlights the typical presentation of pheochromocytomatosis, a rare complication of adrenalectomy for pheochromocytoma. Previous cases and ours collectively demonstrate that tumor capsule rupture during adrenalectomy is a risk factor for pheochromocytomatosis. We also report a novel TMEM127 mutation in this case.

Learning points:

  • Pheochromocytomatosis is a very rare form of pheochromocytoma recurrence.

  • Pheochromocytomatosis refers to new, multiple and often small pheochromocytomas growing in and around the surgical resection bed of a previous adrenalectomy for a solitary pheochromocytoma.

  • Tumor capsule rupture during adrenalectomy predisposes a patient to develop pheochromocytomatosis.

  • Surgical resection of the multiple tumors of pheochromocytomatosis is recommended.

  • Pheochromocytoma recurrence should prompt genetic testing for syndromic pheochromocytoma.

Open access

Eva Krčálová, Jiří Horáček, Lubomír Kudlej, Viera Rousková, Blanka Michlová, Irena Vyhnánková, Jiří Doležal, Jaroslav Malý and Pavel Žák

Summary

Radioiodine (RAI) has played a crucial role in differentiated thyroid cancer treatment for more than 60years. However, the use of RAI administration in patients with papillary thyroid microcarcinoma (even multifocal) is now being widely discussed and often not recommended. In accordance with European consensus, and contrary to the American Thyroid Association (ATA) guidelines, we recently performed RAI thyroid remnant ablation in a patient with differentiated papillary multifocal microcarcinoma. The post-therapeutic whole-body scan and SPECT/CT revealed the real and unexpected extent of disease, with metastases to upper mediastinal lymph nodes. This finding led to the patient’s upstaging from stage I to stage IVa according to the American Joint Committee on Cancer/International Union Against Cancer criteria.

Learning points

  • 131I is a combined beta–gamma emitter, thus allowing not only residual thyroid tissue ablation but also metastatic tissue imaging.

  • RAI remnant ablation omission also means post-treatment whole-body scan omission, which may lead to disease underestimation, due to incorrect nodal and metastatic staging.

  • RAI should be considered also in “low-risk” patients, especially when the lymph node involvement is not reliably documented.

  • Lower administered RAI activity (30mCi, 1.1GBq) may be a workable compromise in low-risk patients, not indicated for RAI remnant ablation according to ATA guidelines.

Open access

Jin-Ying Lu, Po-Ju Hung, Pei-Lung Chen, Ruoh-Fang Yen, Kuan-Ting Kuo, Tsung-Lin Yang, Chih-Yuan Wang, Tien-Chun Chang, Tien-Shang Huang and Ching-Chung Chang

Summary

We report a case of follicular thyroid carcinoma with concomitant NRAS p.Q61K and GNAS p.R201H mutations, which manifested as a 13.5 cm thyroid mass with lung, humerus and T9 spine metastases, and exhibited good response to radioactive iodine treatment.

Learning points

  • GNAS p.R201H somatic mutation is an activating or gain-of-function mutation resulting in constitutively activated Gs-alpha protein and downstream cAMP cascade, independent of TSH signaling, causing autonomously functioning thyroid nodules.

  • NRAS p.Q61K mutations with GNAS p.R201H mutations are known for a good radioactive iodine treatment response.

  • Further exploration of the GNAS-activating pathway may provide therapeutic insights into the treatment of metastatic follicular carcinoma.

Open access

Benjamin G Challis, Nicolai J Wewer Albrechtsen, Vishakha Bansiya, Keith Burling, Peter Barker, Bolette Hartmann, Fiona Gribble, Stephen O'Rahilly, Jens J Holst and Helen L Simpson

Summary

Pancreatic neuroendocrine tumours (pNETs) secreting proglucagon are associated with phenotypic heterogeneity. Here, we describe two patients with pNETs and varied clinical phenotypes due to differential processing and secretion of proglucagon-derived peptides (PGDPs). Case 1, a 57-year-old woman presented with necrolytic migratory erythema, anorexia, constipation and hyperinsulinaemic hypoglycaemia. She was found to have a grade 1 pNET, small bowel mucosal thickening and hyperglucagonaemia. Somatostatin analogue (SSA) therapy improved appetite, abolished hypoglycaemia and improved the rash. Case 2, a 48-year-old male presented with diabetes mellitus, diarrhoea, weight loss, nausea, vomiting and perineal rash due to a grade 1 metastatic pNET and hyperglucagonaemia. In both cases, plasma levels of all measured PGDPs were elevated and attenuated following SSA therapy. In case 1, there was increased production of intact glucagon-like peptide 1 (GLP-1) and GLP-2, similar to that of the enteroendocrine L cell. In case 2, pancreatic glucagon was elevated due to a pancreatic α-cell-like proglucagon processing profile. In summary, we describe two patients with pNETs and heterogeneous clinical phenotypes due to differential processing and secretion of PGDPs. This is the first description of a patient with symptomatic hyperinsulinaemic hypoglycaemia and marked gastrointestinal dysfunction due to, in part, a proglucagon-expressing pNET.

Learning points

  • PGDPs exhibit a diverse range of biological activities including critical roles in glucose and amino acid metabolism, energy homeostasis and gastrointestinal physiology.

  • The clinical manifestations of proglucagon-expressing tumours may exhibit marked phenotypic variation due to the biochemical heterogeneity of their secreted peptide repertoire.

  • Specific and precise biochemical assessment of individuals with proglucagon-expressing tumours may provide opportunities for improved diagnosis and clinical management.

Open access

Sally K Abell, Jessie Teng, Anthony Dowling, Michael S Hofman, Richard J MacIsaac and Nirupa Sachithanandan

Summary

This paper details the case of a 77-year-old male with refractory hypoglycaemia due to inoperable metastatic pancreatic neuroendocrine tumour (pNET) co-secreting insulin and gastrin. Multiple medical therapies were trialled with limited success, and we describe the complications experienced by our patient. Somatostatin analogues can ameliorate hypoglycaemia and may have tumour-stabilising effects; however, in our case resulted in paradoxical worsening of hypoglycaemia. This rendered our patient hospital dependent for glycaemic support including continuous dextrose infusion. Although this is a reported adverse effect with initiation of therapy, we describe successful initiation of short-acting octreotide as an inpatient followed by commencement of long-acting octreotide. Hypoglycaemic collapse occurred only after dose titration of long-acting octreotide. We outline the pitfalls of somatostatin analogue therapy and the mechanisms that may contribute to worsening hypoglycaemia. This rare side effect cannot be reliably predicted, necessitating close supervision and glucose monitoring during therapy. Our patient achieved disease stabilisation and gradual resolution of hypoglycaemia with peptide receptor radionuclide therapy (PRRT), an emerging therapeutic option for metastatic neuroendocrine tumours with high efficacy and low toxicity. We present a brief but comprehensive discussion of currently available and novel therapies for insulin secreting pNETs.

Learning points

  • Hypoglycaemia due to malignant insulin secreting pNET is frequently severe and may be life-threatening despite supportive therapies.

  • Octreotide can ameliorate hypoglycaemia, and may have anti-proliferative and tumour-stabilising effects in malignant pNETs that are surgically unresectable.

  • Paradoxical worsening of hypoglycaemia may occur with octreotide initiation and dose titration, necessitating close supervision and glucose monitoring.

  • PRRT is emerging as a therapeutic option with high efficacy and low toxicity.

Open access

Chiara Baratelli, Maria Pia Brizzi, Marco Tampellini, Giorgio Vittorio Scagliotti, Adriano Priola, Massimo Terzolo, Anna Pia and Alfredo Berruti

Summary

Insulinoma is a rare form of insulin-secreting pancreatic islet cell neuroendocrine (NE) tumor. The medical treatment of the malignant NE disease of the pancreas deeply changed in the last years, thanks to the introduction of new target molecules, as everolimus. Even if the exact mechanism is not actually known, one of the side effects of everolimus, hyperglycemia, has been demonstrated to be useful to contrast the typical hypoglycemia of the insulinoma. We report the case of a patient with a metastatic malignant insulinoma treated with intermittent everolimus, obtaining an important improvement in the quality of life; this suggests the necessity of preclinical studies to analyze the cellular pathways involved in insulin-independent gluconeogenesis.

Learning points

  • Effect of somatostatin analogs is long-lasting in the control of functioning NE tumors.

  • Persistent everolimus control of hypoglycemia despite serum insulin levels and disease progression.

  • Open issue: are disease progression and the increase in serum markers the only valid criteria to reject a treatment?

Open access

S Solomou, R Khan, D Propper, D Berney and M Druce

Summary

A 33-year-old male was diagnosed with a metastatic neuroendocrine carcinoma of uncertain primary. He defaulted from follow-up without therapy and some months later developed episodic severe hypoglycaemia, which was found to be associated with inappropriately elevated insulin and C-peptide levels. It was considered likely that the neuroendocrine tumour was the source of the insulin secretion. Diazoxide and somatostatin analogue were used to control hypoglycaemia. Much later in the course of the disease, he developed metabolic derangement, increased skin pigmentation and psychological disturbance, without frankly Cushingoid physical findings. Investigations revealed highly elevated cortisol levels (the levels having previously been normal) with markedly raised ACTH levels, consistent with the co-secretion of ACTH and insulin by the tumour. Treatment with metyrapone improved his psychological state and electrolyte imbalance. Unfortunately, despite several cycles of first-, second- and third-line chemotherapy from the start of the first hormonal presentation onwards, imaging revealed widespread progressive metastatic disease and the patient eventually passed away. This case highlights the importance of keeping in mind the biochemical heterogeneity of endocrine tumours during their treatment.

Learning points

  • The clinical presentation of insulin-secreting tumours includes symptoms of neuroglycopaenia and sympathetic overstimulation.

  • Tumour-associated hypoglycaemia can be due to pancreatic insulinomas, and although ectopic hormone production occurs in a number of tumours, ectopic secretion of insulin is rare.

  • A possible switch in the type of hormone produced can occur during the growth and progression of neuroendocrine tumours and, when treating neuroendocrine tumours, it is important to keep in mind their biochemical heterogeneity.