Summary

Pregnancy in the setting of metastatic paraganglioma is challenging, particularly in the context of tyrosine kinase use. We describe a 26-year-old female with a background of metastatic paraganglioma harboring a pathogenic SDHB variant, requiring sunitinib, which was withheld to facilitate the safe conception and delivery of a healthy baby. She required no alpha- or beta-blockade during her pregnancy and exhibited no signs of tumor progression or symptoms throughout this period. Historically, higher rates of fetal and maternal morbidity and mortality have been experienced in the setting of pregnancy. Although limited data exist on the management of metastatic paraganglioma in pregnant patients, this case suggests that careful treatment modifications, such as temporary tyrosine kinase therapy cessation and vigilant monitoring, can result in successful pregnancies without compromising maternal or fetal well-being.

Learning points

• Paraganglioma in pregnancy has been associated with poor fetal and maternal morbidity and mortality.

• Many of the treatment modalities for metastatic paraganglioma, including tyrosine kinase inhibitors, can affect fertility or cannot be utilized in pregnancy, necessitating the temporary suspension of these treatments.

• This case exemplifies that careful clinical and biochemical monitoring during pregnancy is required to avoid maternal and fetal harm while balancing the risk of disease progression off treatment.

Summary

X-linked hypophosphatemic rickets (XLH), the most prevalent form of inherited hypophosphatemic rickets, is caused by loss-of-function mutations in the gene encoding phosphate-regulating endopeptidase homolog, X-linked (PHEX). This case series presents 14 cases of XLH from Gulf Cooperation Council (GCC) countries. The patients’ medical history, biochemical and radiological investigative findings, as well as treatment responses and side effects from both conventional and burosumab therapy, are described. Cases were aged 2–40 years at diagnosis. There were two male cases and 12 female cases. All cases were treated with conventional therapy which resulted in a lack of improvement in or worsening of the clinical signs and symptoms of rickets or biochemical parameters. Side effects of conventional therapy included nausea, diarrhea, abdominal pain, nephrocalcinosis, and hyperparathyroidism, which affected the patients’ quality of life and adherence to treatment. In the 10 patients treated with burosumab, there was a marked improvement in the biochemical markers of rickets, with a mean increase in serum phosphate of +0.56 mmol/L and tubular maximum phosphate reabsorption (TmP) to glomerular filtration rate (GFR) ratio (TmP/GFR) of +0.39 mmol/L at 12 months compared to baseline. Furthermore, a mean decrease in serum alkaline phosphatase (ALP) of −80.80 IU/L and parathyroid hormone (PTH) of −63.61 pmol/L at 12 months compared to baseline was observed in these patients. Additionally, patients treated with burosumab reported reduced pain, muscle weakness, and fatigue as well as the ability to lead more physically active lives with no significant side effects of treatment.

Learning points

• Conventional therapy resulted in a suboptimal response, with a lack of improvement of clinical signs and symptoms.

• Side effects of conventional therapy included nausea, diarrhea, abdominal pain, nephrocalcinosis, and hyperparathyroidism, which affected the patients’ quality of life and adherence to treatment.

• Burosumab demonstrated marked improvements in the biochemical markers of rickets, in addition to reducing pain, muscle weakness, and fatigue.

• There were no significant side effects associated with burosumab therapy.

Summary

Non-islet cell tumour hypoglycemia (NICTH), typically mediated by insulin-like growth factor 2 (IGF-2), is a rare but highly morbid paraneoplastic syndrome associated with tumours of mesenchymal or epithelial origin. Outside of dextrose administration and dietary modification which provide transient relief of hypoglycemia, resection of the underlying tumour is the only known cure for NICTH. Available medical therapies to manage hypoglycemia include glucocorticoids, recombinant growth hormone, and pasireotide. We report two cases of IGF-2 mediated hypoglycemia. The first was managed surgically to good effect, highlighting the importance of a timely diagnosis to maximise the likelihood of a surgical cure. The second patient had unresectable disease and was managed medically, adding to a growing number of cases supporting the efficacy of glucocorticoids and recombinant growth hormone in NICTH.

Learning points

• Recurrent fasting hypoglycemia in the setting of a malignancy should raise suspicion of non-islet cell tumour hypoglycemia (NICTH), which is typically mediated by IGF-2.

• The initial workup for NICTH should include a serum glucose, C-peptide, insulin, insulin antibodies, beta-hydroxybutyrate, IGF-2, IGF-1, and sulphonylurea screen during a spontaneous or induced hypoglycemic episode.

• An IGF-2/IGF-1 ratio above 10 is highly suggestive of IGF-2-mediated hypoglycemia if the IGF-2 level is normal or elevated. False positives may be seen with sepsis and cachexia as both IGF-2 and IGF-1 are subnormal in these cases. A low IGF binding protein 3 (IGFBP3), such as in renal failure, may also result in a falsely normal or low IGF-2/IGF-1 ratio.

• Surgical resection of the associated tumour is curative in most NICTH cases.

• When the tumour is unresectable, moderate-dose glucocorticoids, low-dose glucocorticoids in combination with recombinant growth hormone, and pasireotide are medical therapies with promising results in controlling NICTH.

Summary

Carcinoid heart disease is a rare complication of carcinoid syndrome, resulting in right-sided valvular heart disease and subsequent heart failure due to long-term exposure to vasoactive substances. The management of this condition is complex, often requiring surgical intervention. Current perioperative regimens entail the use of prophylactic somatostatin analogs to prevent carcinoid crisis; however, regimens vary widely among practitioners and evidence supporting their efficacy in this clinical setting is mixed. This case report describes the perioperative management of a 65-year-old man with carcinoid heart disease requiring tricuspid and pulmonary valve replacement surgery. As an adjunct to somatostatin analog therapy, the novel tyrosine hydroxylase inhibitor, telotristat, was initiated preoperatively. This combination resulted in normalization of preoperative urinary 5-HIAA levels. The patient successfully underwent tricuspid and pulmonic valve replacement without evidence of carcinoid crisis. This clinical case is the first published documenting the use of telotristat in the perioperative period in a patient with carcinoid syndrome and carcinoid heart disease and was associated with a good long-term outcome despite the high-risk nature of the case.

Learning points

• Carcinoid crisis is a life-threatening complication of carcinoid syndrome, resulting in hemodynamic instability, bronchospasm, and arrhythmia.

• Cardiac surgical patients with carcinoid syndrome present a unique challenge as they are subject to physiologic conditions and medications which can potentiate intraoperative carcinoid crisis.

• Perioperative management of patients with carcinoid syndrome currently entails the use of prophylactic somatostatin analogs; however, these agents do not prevent carcinoid crisis in all cases.

• Telotristat, a tryptophan hydroxylase inhibitor, shows promise as an adjunctive therapy to somatostatin analogs to reduce the risk of intraoperative carcinoid crisis.

Summary

In patients with diabetes mellitus, the toxic milieu caused by abnormal glucose and free fatty acid handling can lead to heart failure (HF). Referred to as diabetic cardiomyopathy (DMCM), this syndrome often exists in the absence of conventional risk factors for HF such as history of myocardial infarction or hypertension. Low-carbohydrate diets (LCDs) have recently been endorsed as an efficacious therapeutic dietary approach to prevent and reverse cardiometabolic disease including type 2 diabetes mellitus (T2DM). LCDs improve systemic insulin resistance (IR), reverses cardiac remodelling in a rodent model and downregulates the expression of sodium–glucose co-transporter 2 (SGLT2) receptors in the kidney. It is therefore conceivable that a lifestyle approach such as adopting an LCD can be offered to patients with DMCM. The reported case is that of a 45-year-old man with a 15-year history of non-ischaemic cardiomyopathy, T2DM and obesity. The patient volunteered to engage in a 16-week low-carbohydrate dietary intervention trial and then self-selected to remain on this diet for 1 year. The whole-food LCD was based on simple ‘traffic light’ style food lists and not designed to restrict calories, protein, fat or salt. After 1 year, the patient had lost 39 kg and his cardiometabolic markers had significantly improved. LCDs present a potentially beneficial approach for patients with DMCM and could be considered as a lifestyle intervention before SGLT2i therapy is commenced.

Learning points

• Diabetic cardiomyopathy (DMCM) is a syndrome precipitated mainly by the detrimental effects of glucose metabolism disorders such as insulin resistance and diabetes.

• Low-carbohydrate diets (LCD) mimic many effects of sodium–glucose co-transporter 2 inhibitors (SGLT2i).

• LCDs are a dietary pattern which can have significant and beneficial effects on metabolic and anthropometric markers in patients with DMCM.

• LCDs and SGLT2i therapy could be combined and may achieve better clinical outcomes for patients with DMCM.

• Combination therapy may be carried out under close supervision as the real risk for diabetic ketoacidosis remains.

Summary

Severe Cushing’s syndrome from an ectopic adrenocorticotropic hormone-producing tumour is rare but often demands rapid diagnostics and treatment of hypercortisolism with its comorbidities. Pharmacotherapy of hypercortisolism by ketoconazole, metyrapone and osilodrostat is currently available. If unsuccessful or insufficient a bilateral adrenalectomy is an option. We present a 28-year-old female with severe Cushing’s syndrome caused by a bronchial metastatic neuroendocrine tumour (NET). Hypercortisolism was efficiently treated by osilodrostat with block–replace and then titration regimen. A once-daily dose was finally used with normalised cortisol levels. Androgen levels measured by liquid chromatography–mass spectrometry were slightly elevated during the treatment but without any symptoms. A simple once-daily use of osilodrostat with titration regimen led to normalised cortisol levels in a severe Cushing’s syndrome patient with an uncurable bronchial NET. Transient hypocortisolism during treatment appeared but was easily treated by hydrocortisone.

Learning points

• Cushing’s syndrome from an ectopic adrenocorticotropic hormone-producing tumour is rare.

• Cortisol upregulation is often severe and rapid, though clinical signs are not always fully pronounced.

• Rapid treatment is a key for preventing and reducing complications such as fractures, thromboembolism, bleeding, hyperglycaemia, and arterial hypertension.

• The novel potent steroidogenesis inhibitor osilodrostat can be used as first-line treatment for reducing hypercortisolism.

Summary

A 33-year-old man with Kallmann syndrome had received pulsatile GnRH as an infant for the treatment of cryptorchidism. As an adult, his treatment for fertility with gonadotrophins was unusually rapid compared with expectations, with a total sperm count of 25 million after only 12 months of gonadotrophin therapy. We propose that pulsatile GnRH treatment as an infant induced minipuberty and facilitated his successful, rapid response to therapy. We also propose that identification of the absence of minipuberty in infants with clinical signs suggesting congenital hypogonadotrophic hypogonadism (CHH) is an opportunity for intervention with pulsatile GnRH yielding benefits for fertility decades later.

Learning points

• Absence of minipuberty in males with CHH results in low Sertoli cell numbers and delayed response to induction of spermatogenesis in adulthood.

• Presentation with 'red flags' for androgen deficiency including cryptorchidism at birth, with or without micropenis, should prompt screening for CHH and minipuberty by measurement of gonadotrophins and testosterone in the first 2 months after birth.

• Pulsatile GnRH therapy in patients with CHH, given prior to age of attainment of Sertoli cell maturation, can replicate the normal physiology of minipuberty, thereby priming the testis for future fertility.

Summary

The COVID-19 pandemic has led to the emergence of telemedicine on a global scale. In endocrinology, telemedicine has mainly been used in relation to chronic diseases, including diabetes. Herein, we report the case of an 18-year-old woman with a hypertensive emergency due to a pheochromocytoma who was quickly diagnosed and treated using telemedicine. The patient was referred to a cardiovascular hospital because of fatigue and sweating that did not improve with carvedilol. She had fluctuating blood pressure and tachycardia. Subsequently, since her thyroid function was normal, endocrine hypertension not due to thyroid dysfunction was suspected; a case consultation was made by phone to our clinic. Plain computed tomography (CT) was recommended owing to the high possibility of a pheochromocytoma; the CT scan showed an adrenal tumor with a 30 mm diameter. To assess her condition, endocrinologists, together with the attending doctor, interviewed her and her family directly using an online tool to obtain detailed information. We thus determined that she was at risk of a pheochromocytoma crisis. She was transferred to our hospital immediately for treatment, was diagnosed with pheochromocytoma, and underwent surgery. Telemedicine, especially involving doctor-to-patient with doctor consultations, can be effective in treating rare and emergent medical conditions such as pheochromocytoma crisis.

Learning points

• Telemedicine can be used for chronic diseases and emergency conditions.

• Online doctor-to-patient with doctor (D-to-P with D) consultations are useful when the expert opinion of a highly specialized physician present in a different geographical location is required.

• Telemedicine, especially D-to-P with D online consultations, can be effectively used for the diagnosis of rare and emergent medical conditions, such as pheochromocytoma crisis.

Summary

Triglyceride deposit cardiomyovasculopathy (TGCV) is an intractable disease characterized by massive triglyceride (TG) accumulation in the myocardium and coronary arteries caused by genetic or acquired dysfunction of adipose TG lipase (ATGL). A phase IIa trial has been conducted involving patients with idiopathic TGCV using CNT-01 (tricaprin/trisdecanoin) by the Japan TGCV study group, which showed that CNT-01 improved myocardial lipolysis as demonstrated by iodine-123-beta-methyl iodophenyl-pentadecanoic acid (BMIPP) scintigraphy. We evaluated changes in myocardial TG content using proton magnetic resonance spectroscopy (¹H-MRS) before/after CNT-01. This report describes a male patient with hypertension, diabetes, angina pectoris, repeated percutaneous coronary intervention, chest pain, and exertional dyspnea that persisted despite standard medications and nitroglycerin. Idiopathic TGCV was diagnosed based on a remarkably reduced washout rate (WR) for BMIPP scintigraphy, high myocardial TG content on ¹H-MRS, and no ATGL mutation. After an 8-week, 1.5 g/day CNT-01 administration, the WR of BMIPP increased from 5.1 to 13.3% and the myocardial TG content decreased from 8.4 to 5.9%, with no adverse effects. CNT-01 corrected myocardial lipolysis and subsequently reduced TG content in idiopathic TGCV as evaluated using ¹H-MRS, which may be a useful, noninvasive evaluation of therapeutic efficacy.

Learning points

• Triglyceride deposit cardiomyovasculopathy (TGCV) is an intractable disease characterized by massive triglyceride accumulation in the myocardium and coronary arteries, caused by genetic or acquired dysfunction of adipose triglyceride lipase.

• Japan TGCV Study Group developed a specific treatment for idiopathic TGCV using CNT-01 (tricaprin/trisdecanoin), a type of medium-chain fatty acid.

• CNT-01 corrected myocardial lipolysis and reduced TG content in idiopathic TGCV using proton magnetic resonance spectroscopy, which may be a useful noninvasive evaluation of therapeutic efficacy.

Summary

Doege–Potter syndromeis a paraneoplastic syndrome characterized by nonislet cell tumor hypoglycemia due to a solitary fibrous tumor, which produces insulin-like growth factor II. In this report, we present the case of a 67-year-old male with recurrent and refractory hypoglycemia due to DPS successfully treated with imatinib. He initially presented with neuroglycopenic symptoms and dyspnea secondary to a giant tumor in the left hemithorax, which was totally resected. During follow-up, 7 years later, he presented with thoracoabdominal tumor recurrence associated with severe hypoglycemia and underwent subtotal tumor resection, with a subsequent improvement of symptoms. The following year, he had a recurrence of his intra-abdominal tumor, which was unresectable, associated with severe hypoglycemia refractory to dextrose infusion and corticosteroids, thus receiving imatinib with a favorable response. The clinical presentation, diagnostic approach, progression of the disease, and response to treatment with imatinib in the management of a patient with large, recurrent, and unresectable mesenchymal tumors with insulin-like growth factor-2 secretion causing hypoglycemiahighlight the importance of this case report.

Learning points

• Doege–Potter syndrome (DPS) is a rare cause of tumoral hypoglycemia of non-pancreatic origin.

• Some malignant or benignant neoplasms have ectopic secretion of insulin-like growth factor-2.

• Total surgical removal is the principal treatment in patients with DPS.

• Tyrosine kinase inhibitors management in DPS may contribute to improved tumor control in patients with unresectable tumors and severe hypoglycemia.